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Apocalypse_Now
02-02-2008, 19:26
I'm guessing this has been beaten to death in some old thread but after many Glockless years I'm going to buy several Glocks. (G22 and a G21 w G20 conversion)I'm wondering if hard cast, properly lubed bullets (I tend to use Lee tumble lube bullets) are OK to use in Glocks if a few lead-chaser JHPs are at the bottom of each mag and if a Lewis tool is used to keep the bore clean?

I remember reading years ago they were supposed to be a no-no with polygonal rifling.. was that an old wive's tale? I didn't use my lead bullet loads in the G17 I had way back then, because of this. I'm planning on an aftermarket standard rifled barrel for this use but I'm also curious about the stock barrel and lead loads.. thanks in advance

Steve Koski
02-02-2008, 19:39
It all depends on the bullets (and your load and other stuff), but there's no way to know in advance. You have to do some testing to see how quickly the lead builds up. Some combos lead badly in 30 rounds, others can fire hundreds without significant leading.

Apocalypse_Now
02-02-2008, 21:56
It all depends on the bullets (and your load and other stuff), but there's no way to know in advance. You have to do some testing to see how quickly the lead builds up. Some combos lead badly in 30 rounds, others can fire hundreds without significant leading.

Well my tumble lube hard cast loads hardly lead a barrel at all.. just a few JHPs at the end of the session and a pass or two with the lead remover tool cleans out even revolvers.

I also water-quench the bullets into a half full 5 gallon bucket of cold water as they drop out of the mold

Jake44460
02-02-2008, 22:02
Some combos lead badly in 30 rounds,

Such as.......:dunno: ?

I'm looking to shoot lead in the not to distant future. Stock barrel.

I'll take any good advice on loads in 9/45 acp

Apocalypse_Now
02-02-2008, 22:13
Improperly lubed lead bullets can badly cake up a bore with an unreal amount of shavings and lead coating.. Many factory bulk lead bullets are in this camp.. I wouldn't buy them unless you get reviews first.

For pistol bullets I use the 6 cavity Lee tumble lube bullet molds. No bullet sizing required. You cast 'em (I quench as listed above) dry them out (I use a large piece of cardboard or several cardboard box tops from printing/typing paper boxes)

Then use a coffee can or similar (1 lb size is perfect) fill it 1/3 full of bullets, add the proper amount of the Lee tumble lube, shake well and pour them out on the cardboard or a piece of plywood. In warm weather or inside they will dry in a few hours. Make sure you have fully coated the entire bullet. The lube will dry semi-hard. I make sure none are resting on their base while they dry.. to ensure they are fully coated there and don't stick to the surface.

Then simply load 'em or tuck away for your next project. I wouldn't say they are true match quality but plenty accurate for self defense training and small game shooting such as rabbits

CaptJim
02-03-2008, 19:04
I have shot lots of lead in my Glock. BUT, have changed over to the Master Blaster polymer-coated RNFP for my Glock 45. Shoots cleaner, with higher velocity than equivalent lead bullets. A little more expensive, but worth it IMHO.

Jim

AlPackin
02-03-2008, 19:05
I believe Master Blaster is out of business

sig2009
02-03-2008, 19:27
KEAD Bullets are hardcast and will not lead up your Glock barrel.

Apocalypse_Now
02-03-2008, 23:38
So it seems with the right lube (or purchased bullets) and care to keep the barrel clean of extra lead particles there's no problem.. ?

I long suspected this but never really had to test the theory on polygonal rifling

MakeMineaP99
02-04-2008, 00:05
So it seems with the right lube (or purchased bullets) and care to keep the barrel clean of extra lead particles there's no problem.. ?

I long suspected this but never really had to test the theory on polygonal rifling

There's a whole lot more to the equation than that. Poly bores require lead sized differently than conventionally rifled bores.

A poly bore actually compresses the bullet and rotates it about an axis where as a conventional bore only causes the bullet to rotate around an axis. Due to this, this is the reason for jacketed bullets being recommended in poly bores, from Glock, H&K, et al.

The first step in running lead in any poly bore is to slug the barrel. I bet you'll find that lead should be sized one or two thousands over conventional deminsions for the bore. Most 9mm lead is .356", a Glock needs .358", generally. An undersize bullet will lead to leading, all the time, every time.

Also, hard cast isn't always better. Upon firing, the bullet "expands" from the pressure to seal the bore. In a low pressure round, like .45 ACP, a 11 BHN will expand sufficiently. In 9mm though, something harder, maybe in the 22 BHN range, is needed to seal the bore under the higher pressure. Have an improperly hardened bullet, you will experience leading, since it won't seal the bore and lead to gas cutting.

Don't forget twist and bore profile (hex vs. oct) either. 9mm and .40 are naturally less friendly because of more agressive rifling and hex bore profile, compared to .45 and will require a bit more due diligence.

Lube also plays a part. Lar's Red works well in most pistol applications and most rifle applications. Any good commericial lube should do, ALOX, LLA, Lar's, SPG, et al, or home made lube (Felix).

Apocalypse_Now
02-04-2008, 00:08
Thank you, that was truly helpful ! :thumbsup:

MakeMineaP99
02-04-2008, 00:18
Forgot to address this in the earlier post, those of you who think that a few jacketed or plated bullets will shoot out the lead in a barrel at the end of a shooting session, need to go back to physics class.

When a bullet passes through the barrel, the barrel expands around the bullet, like a snake eating a mouse, as it accelerates through the barrel. Firing a jacketed bullets serves to "iron" the lead into the pores of the steel making it harder to remove.

If you have severe leading, jacketed bullets can cause unsafe pressures and at worst, cause a barrel bulge or burst. Remember, metals and most fluids are incompressible and will cause pressure (force/area) on the barrel walls.

Get a chore boy or Lewis lead remover.

Apocalypse_Now
02-04-2008, 01:02
Forgot to address this in the earlier post, those of you who think that a few jacketed or plated bullets will shoot out the lead in a barrel at the end of a shooting session, need to go back to physics class.

When a bullet passes through the barrel, the barrel expands around the bullet, like a snake eating a mouse, as it accelerates through the barrel. Firing a jacketed bullets serves to "iron" the lead into the pores of the steel making it harder to remove.

If you have severe leading, jacketed bullets can cause unsafe pressures and at worst, cause a barrel bulge or burst. Remember, metals and most fluids are incompressible and will cause pressure (force/area) on the barrel walls.

Get a chore boy or Lewis lead remover.

Re-read my post. I use a few JHPs (Or other jacketed bullets) at the bottom of each mag to blow some of the lead out and keep it at a minimum until the shoot is over. This works excellently in my experience with good, well-lubed lead loads. Yes there is lead left to remove when you clean with a lead remover tool but it's less with the "chaser" rounds added to the mix

Blitzer
02-04-2008, 02:08
Glock says no reloads, your choice.

:upeyes: :dunno: :whistling:

sig2009
02-04-2008, 08:22
Glock says no reloads, your choice.

:upeyes: :dunno: :whistling:

Ya. And my BMW says premium fuel only. Guess what! It also runs on 87 octane with no problem and that after about 10 years. Don't believe everything the manufacturers tell you.

AngelDeville
02-04-2008, 09:04
I already have the 200grain bullet mould for my future G20, I expect no problems.

Frostback
02-04-2008, 09:18
I have fired thousands of rounds of lead out of my factory barrel G-19 with no problems. I have found that using slower powders also reduces the amount of leading. You may want to experiment with that too.

Frosty

MakeMineaP99
02-04-2008, 11:06
Re-read my post. I use a few JHPs (Or other jacketed bullets) at the bottom of each mag to blow some of the lead out and keep it at a minimum until the shoot is over. This works excellently in my experience with good, well-lubed lead loads. Yes there is lead left to remove when you clean with a lead remover tool but it's less with the "chaser" rounds added to the mix


I read your post,

if a few lead-chaser JHPs are at the bottom of each mag

This BS and an internet myth. JHPs and other jacketed bullets do not remove lead, they "iron" it into the barrel.

Steel, like all materials, will elastically deform until it reaches its yield point, which will then plastically deform. The steel will "expand"--elastically deform, like a snake eating a mouse, when a bullet passes through the barrel. Obstructions, whether lead, water, sand, grit, etc. will cause an additional force to be applied over an area (pressure). If that pressure becomes greater than the yield strength of the material, meaning that you have reached and exceed the yield point, the barrel will bugle or if stressed to the failure point, burst.

Metals and most fluids (water among them) are incompressible, meaning if they are in a barrel when a force is exerted (bullet being accelerated has force), the force will be exerted on them, meaning they will stress the barrel.

Can you get away with it? Sure, all designs incorporate a factor of safety. Does that make it the smart thing to do? Not really.

Lewis lead remover is good stuff.

Jake44460
02-04-2008, 20:24
Thanks for the physics lesson!

Nice post.

cz93x62
02-05-2008, 04:08
Thanks for the physics lesson!

Nice post.

+1 to that.

I agree with P-99's position on shooting jacketed bullets over any potential lead deposits in any barrel. Before going to jacketed bullets, I clean the lead and lube FASTIDIOUSLY from a barrel. The Chore Boy fibers--wrapped around a played-out bore brush, then soaked in Hoppe's--will get out a SURPRISING amount of plomocaca.

It goes the other way, too--get ALL of the copper jaclet fouling from a barrel before shooting lead through it. Copper deposits will cheerfully strip lead from the bullet as it passes over, and get that bore leaded for you in short order. Hoppe's or CLP will de-copper a bore over time, if you want to hurry the process use Sweet's 7.62 or some other ammonia-based solvent. DO NOT leave ammonia-based solvents in place for more than 10 minutes--swab them out, dilute the residual ammonia with a couple wet patches of Hoppe's or CLP, then dry-patch that stuff out. Repeat as needed.

rem243
02-15-2008, 03:52
I read your post,



This BS and an internet myth. JHPs and other jacketed bullets do not remove lead, they "iron" it into the barrel.

Steel, like all materials, will elastically deform until it reaches its yield point, which will then plastically deform. The steel will "expand"--elastically deform, like a snake eating a mouse, when a bullet passes through the barrel. Obstructions, whether lead, water, sand, grit, etc. will cause an additional force to be applied over an area (pressure). If that pressure becomes greater than the yield strength of the material, meaning that you have reached and exceed the yield point, the barrel will bugle or if stressed to the failure point, burst.

Metals and most fluids (water among them) are incompressible, meaning if they are in a barrel when a force is exerted (bullet being accelerated has force), the force will be exerted on them, meaning they will stress the barrel.

Can you get away with it? Sure, all designs incorporate a factor of safety. Does that make it the smart thing to do? Not really.

Lewis lead remover is good stuff.

Sounds like a new invention. A brass (or Glock barrel safe material) brush bullet. You load up a few for each batch of lead bullets shot. Then at the end of you session you can just shoot a few brushes down the barrel and call it a day. Sounds like it could make a few dollars? Maybe even Billy Mays could sell it on an infomercial and add some Orange scent to it.

cvfl
02-15-2008, 07:35
Sounds like a new invention. A brass (or Glock barrel safe material) brush bullet. You load up a few for each batch of lead bullets shot. Then at the end of you session you can just shoot a few brushes down the barrel and call it a day. Sounds like it could make a few dollars? Maybe even Billy Mays could sell it on an infomercial and add some Orange scent to it.
And with that we have found Koski's new test... The ChoreBoy Barrel Brush Bullet.

Concerned about leading at the range? Buy a boresnake and leave it in your range bag with a can of CLP.

cvfl
02-15-2008, 07:50
KEAD Bullets are hardcast and will not lead up your Glock barrel.
+1 - so much so that I sent George an email to start buying in bulk until my casting is up and running.

Although for clarity - they do lead eventually - but i have done 600 in one session without running a boresnake down with no problems. IMO most of the leading in my 26 is not due to melt but rather the round skipping down the barrel.
But as mentioned in prior posts, every barrel/bullet combination will be different, so go forward with your wits about you and observe what is happening along the way.

MakeMineaP99
02-15-2008, 09:15
Maybe even Billy Mays could sell it on an infomercial and add some Orange scent to it.


:rofl: That's comedy right there.

rem243
02-15-2008, 10:30
I read your post,



This BS and an internet myth. JHPs and other jacketed bullets do not remove lead, they "iron" it into the barrel.

Steel, like all materials, will elastically deform until it reaches its yield point, which will then plastically deform. The steel will "expand"--elastically deform, like a snake eating a mouse, when a bullet passes through the barrel. Obstructions, whether lead, water, sand, grit, etc. will cause an additional force to be applied over an area (pressure). If that pressure becomes greater than the yield strength of the material, meaning that you have reached and exceed the yield point, the barrel will bugle or if stressed to the failure point, burst.

Metals and most fluids (water among them) are incompressible, meaning if they are in a barrel when a force is exerted (bullet being accelerated has force), the force will be exerted on them, meaning they will stress the barrel.

Can you get away with it? Sure, all designs incorporate a factor of safety. Does that make it the smart thing to do? Not really.

Lewis lead remover is good stuff.

This sounds like a case for Mythbusters! I find it hard to believe that a barrel actually "expands." I always thought that the bullet was deformed or formed to match the rifling. Now, I guess if the bullet is hard enough and the barrel is thin enough, a little expanding might take place. But what about say a 38 with a 3/8" thick barrel? That baby is not going to expand. Or how about a SS bull barrel on a 10/22? That bullet is not expanding the barrel in the least. The heat is coming from the friction, not expansion.

Like I said this is one for the Mythbusters. I'll it when I see it; say a caliper on a barrel expand after firing (although lateral vibration may though this off), or or if it's on a high speed camera you might be able to see.

Sig, is there scientific proof of this or were you just taught this by someone? Just wondering, not meant to be an attack on you!

I hope I am not starting WWIII with my humble opinion.
I still agree that a copper jacketed bullet shot after lead is not going to magically clean the barrel. That is what bore snakes and brushes are for.

marchboom
02-15-2008, 11:07
Another thing to consider is bullet velocity. There are too many reloaders who think they can load a lead bullet to the same velocities as jacketed bullets. And then they wonder why they have problems with their guns.

Don't "hot rod" lead bullets.

I have shot lead bullets in my Glock 21 for years with no problems. BUT, I load them to conservative velocities. And I clean out the barrel more often.

Have you considered buying another barrel with a conventional rifling just for your cast bullets? Watch for the sales and I'm sure you'll be able to pick up a good one for a decent price. Then you can shoot all the lead you want. And when the day is done, put your Glock barrel back in, along with your defense loads.

MakeMineaP99
02-15-2008, 11:36
This sounds like a case for Mythbusters! I find it hard to believe that a barrel actually "expands." I always thought that the bullet was deformed or formed to match the rifling. Now, I guess if the bullet is hard enough and the barrel is thin enough, a little expanding might take place. But what about say a 38 with a 3/8" thick barrel? That baby is not going to expand. Or how about a SS bull barrel on a 10/22? That bullet is not expanding the barrel in the least. The heat is coming from the friction, not expansion.



BS! The barrel will expand. I trust your not an engineer and don't have a working knowledge of solid mechanics. ALL materials deform, period. There are numberous models and formulas to represent this, FEA, finite element analysis, being the most prevelent.

See: Rinker, Robert A. Understanding Firearm Ballistics, 2nd Edition.

Like I said this is one for the Mythbusters. I'll it when I see it; say a caliper on a barrel expand after firing (although lateral vibration may though this off), or or if it's on a high speed camera you might be able to see.

A computer model will show you the deformation. I'll post a FEA model of a beam deflecting later today.

..........

rem243
02-15-2008, 12:14
..........

No I am not an engineer, but with your reasoning taken to the extreme, means that when I push my plastic Glock cleaning brush through my barrel (it is a larger diameter than the inside of the barrel and will produce an outward force), even this force is going to expand the barrel, at least to some microscopic degree. How about a wax or rubber bullet. Will that also expand the barrel? I say no. And neither will a soft bullet, say a lead one at low velocities. Rather the barrel will deform the bullet to its dimensions like a die on brass.

All I am saying is that there has to be some allowance for hardness of the bullet, velocity, and the thickness of the barrel before we assume that the barrel will "always" expand.

Science has been telling us many things for many years and is always changing their tune. I personally don't believe a bit of Macro-Evolution (there is no legitimate fossil record to back it up) but it is in all the "respected" science books. But this is for another thread.

All I am saying is that not every projectile will expand every barrel. Maybe a jacketed bullet will in a Glock, but maybe not a soft lead one in a heavy revolver barrel.

MakeMineaP99
02-15-2008, 18:12
rem243,

Your problem is that you're thinking intuitivly. Until I got into solid mechanics, dynamics and materials, I thought the same way as you. The key is that our intuition, however "correct" it may seem, is seldom right. You need to learn to the let equations and data "speak to you."

Here's the stress vs. strain curve for mild steel.

http://img252.imageshack.us/img252/7695/sscsteelfn4.jpg

Look at the first region, the elastic region. As stress (load (pressure)/area) increases so does strain. Note the linear relationship, the stress is proportional to the strain (Hooke's Law), up until the yield point, where plastic deformation starts. Therefore, any stress will result in some amount of deformation.

All designs must take into account the elastic deformation of the material and some designs must take into account both elastic and platstic deformation (vehicle crash safety design).

In the case of a firearm, as the bullet passes the barrel, it exerts a stress on the barrel and therefore deforms the barrel. The outside of the barrel is in tension and the inside of the barrel is in compression. While this may sound counter intuitive, think of a pencil. Apply a load at both ends, in the same direction, the top of the pencil is in tension, the bottom in compression.

A cleaning brush, as a bullet, exerts a stress on the barrel, however it's so small as to be negligible, not the case under a dynamic load (firing).

Hardness of the bullet, velocity and thickness of the barrel walls will all have an effect, but deformation will still be present regardless of how thick the barrel walls are or the type of slug. Don't assume a jacketed bullet will cause deformation but a lead bullet won't.

The rate of change of the velocity of the bullet, dV/dt or acceleration, will be proportional to the force. If F=ma (Newton's second law), there must be a force if there is an acceleration. If there is a force over an area, you have a stress.

Solid mechanics is a set science and hasn't change in a while (a couple hundred years).

Here's a FEA (finite element analysis) of an I beam. A light load, 750 ibf is applied. With it may not appear to deform in real life, the beam deforms .005" of an inch, as shown by the FEA model. While negligible in certain cases, it's critical in others.

http://img228.imageshack.us/img228/4259/scenario1aq6.gif

Blitzer
02-15-2008, 18:35
This sounds like a case for Mythbusters! I find it hard to believe that a barrel actually "expands." I always thought that the bullet was deformed or formed to match the rifling. Now, I guess if the bullet is hard enough and the barrel is thin enough, a little expanding might take place. But what about say a 38 with a 3/8" thick barrel? That baby is not going to expand. Or how about a SS bull barrel on a 10/22? That bullet is not expanding the barrel in the least. The heat is coming from the friction, not expansion.

Like I said this is one for the Mythbusters. I'll it when I see it; say a caliper on a barrel expand after firing (although lateral vibration may though this off), or or if it's on a high speed camera you might be able to see.

Sig, is there scientific proof of this or were you just taught this by someone? Just wondering, not meant to be an attack on you!

I hope I am not starting WWIII with my humble opinion.
I still agree that a copper jacketed bullet shot after lead is not going to magically clean the barrel. That is what bore snakes and brushes are for.


Read to find thy self improved.

Search the web for the topic and you will find pages of evidence that speaks for itself. Solids are very slow moving liquids.

:whistling:

SCmasterblaster
02-15-2008, 18:50
Such as.......:dunno: ?

I'm looking to shoot lead in the not to distant future. Stock barrel.

I'll take any good advice on loads in 9/45 acp

I cast my own 155gr LRN flat-base bullets and load them with 2.7 gr HTG. With the excellent Lee liquid alox, I get NO leading @ 830FPS.

Stock G17.

rem243
02-15-2008, 22:54
That is a lot to swallow. At this point I think it wise to throw up the white flag!

I still think it would make a cool Mythbusters show.

Dear Sig
Since you are so much in the know (I am not kidding), I am going to post a new forum that I would like you to answer. Along the lines of whether a fast burning powder will produce less felt recoil in a handgun than slower burning powders.
http://glocktalk.com/forums/showthread.php?p=9879067#post9879067

Steve Koski
02-15-2008, 22:58
God I love engineers (in a very manly sort of non-sexual way).

yammerschooner
02-15-2008, 23:23
I ran about 300 handcast through my G23 stock barrel last night because the dillon dies on my 1050 don't size all the way down like the Lee ones on my 550 did.

Minimal to no leading.

By the way, if you want to get rid of lead, save the money on the lewis lead remover and cut up a copper chore boy (in my case generic hy-vee brand copper scrub pad) It works like a champ. I think I was out $1.67 on the deal.

Never used the lewis, but I can't imagine it working better than the abovementioned elcheapo method.

MakeMineaP99
02-16-2008, 03:12
That is a lot to swallow. At this point I think it wise to throw up the white flag!

I still think it would make a cool Mythbusters show.

Dear Sig
Since you are so much in the know (I am not kidding), I am going to post a new forum that I would like you to answer. Along the lines of whether a fast burning powder will produce less felt recoil in a handgun than slower burning powders.
http://glocktalk.com/forums/showthread.php?p=9879067#post9879067

I hope you found my post informational and everything made sense. Whether I like it or not, not everyone speaks engineer, trying my best to educate everyone.

Intuition is a hard thing to overcome.

I'll take a look at your other thread.

MakeMineaP99
02-16-2008, 03:14
God I love engineers (in a very manly sort of non-sexual way).

Here's the sad part, I don't even have a PE. :supergrin:

Joe D
02-16-2008, 05:40
Lead bullet diameter is very important also. Case in point is some 160 gr moly coated 9mm bullets that I have been using. Moly coated bullets are a good choice for those that want something a little better than lead, but less costly than jacketed/plated.
The first batch I got in leaded in every 9mm gun I owned. Not just a little, but a lot. I tried changing powders, crimp and OAL to no avail. Problem was the bullets were sized to .3555" -.3556". They replaced my order with bullets sized .3565" -.357". Problem solved.
I had been shooting 180 gr Valiant bullets in my G35 for years. No lead issues at all. Got a batch in once that dripped lead out the end of the barrel. Same problem. Bullets were sized .4005". Checked some of my older non-leading bullets. They were sized .401" - .4015".
Powder is very important. Use one that has a very low percentage of nitroglycerin. Titegroup is not good for lead. I have changed to Solo 1000 - no nitro.

4eyes
02-16-2008, 07:42
Here is another way to explain the phenomena: Think of MMAP99 sitting on the toilet. No strain--orifice remains closed. Introduce strain in the form of extrudate--orifice starts to open (bullet leaves chamber). Continued extrudate, continued strain, orifice expanded to nearly full open (bullet in mid bore).Relax strain, slow extrudate, orifice reduces in size (bullet near end of barrel). Stop strain, no extrudate, orifice slams closed (bullet clears bore).

Audible bang in bathroom. No strain and orifice resumes near normal size after cleaning.

;) :whistling:


[QUOTE=MakeMineaP99;9877141]rem243,
Look at the first region, the elastic region. As stress (load (pressure)/area) increases so does strain. Note the linear relationship, the stress is proportional to the strain (Hooke's Law), up until the yield point, where plastic deformation starts. Therefore, any stress will result in some amount of deformation.

All designs must take into account the elastic deformation of the material and some designs must take into account both elastic and platstic deformation (vehicle crash safety design).

Bronson7
02-16-2008, 08:46
Guys, I'm with you on this, but aren't we missing an important part here? What about "cycles to failure"? We can stress metals below yield but the cycles to failure is to me, what's really important here.
If I'm wrong, clear me up.
Bronson7

AlPackin
02-16-2008, 08:53
Audible bang in bathroom. No strain and orifice resumes near normal size after cleaning.

;) :whistling:


I felt that!

MADISON
02-16-2008, 09:19
NO!!!
You can GET AWAY WITH IT FOR UP TO 100 rounds. After that you will spend time removing lead from a leaded barrel.

MakeMineaP99
02-16-2008, 12:10
Guys, I'm with you on this, but aren't we missing an important part here? What about "cycles to failure"? We can stress metals below yield but the cycles to failure is to me, what's really important here.
If I'm wrong, clear me up.
Bronson7

Absolutely. All materials fatigue. However, we’re concerned in showing how stress and strain effect the elastic region of the barrel. Fatigue is outside of the original scope.

Parts are design for a specific amount of cycles, sometimes into the billions (crankshafts on vehicles). Point being, the amount of cycles the average firearm will complete are well below the material fatiguing, which is why you have heard a firearm will "last a life time" or be "handed down three generations."

MakeMineaP99
02-16-2008, 12:10
Here is another way to explain the phenomena: Think of MMAP99 sitting on the toilet. No strain--orifice remains closed. Introduce strain in the form of extrudate--orifice starts to open (bullet leaves chamber). Continued extrudate, continued strain, orifice expanded to nearly full open (bullet in mid bore).Relax strain, slow extrudate, orifice reduces in size (bullet near end of barrel). Stop strain, no extrudate, orifice slams closed (bullet clears bore).

Audible bang in bathroom. No strain and orifice resumes near normal size after cleaning.

;) :whistling:


[QUOTE=MakeMineaP99;9877141]rem243,
Look at the first region, the elastic region. As stress (load (pressure)/area) increases so does strain. Note the linear relationship, the stress is proportional to the strain (Hooke's Law), up until the yield point, where plastic deformation starts. Therefore, any stress will result in some amount of deformation.

All designs must take into account the elastic deformation of the material and some designs must take into account both elastic and platstic deformation (vehicle crash safety design).

Excellent analysis, Bob. Did you have to pick on me? ;)

4eyes
02-16-2008, 13:57
OK, Imagine me on the potty!!!


NAH. Imagine 918v and El-Ron1 on a 2 holer!!!

MakeMineaP99
02-16-2008, 14:15
NAH. Imagine 918v and El-Ron1 on a 2 holer!!!

:wow::shocked:

theghostrider
02-25-2008, 01:24
The first step in running lead in any poly bore is to slug the barrel.
I've seen this mentioned before. Can someone please explain what this is, and how done. I shoot lead from a G19 but manage to keep it clean. Am always looking to improve.

Jake44460
02-25-2008, 02:14
I think it was mentioned that loading light loads helps.

yammerschooner
02-25-2008, 07:58
I've seen this mentioned before. Can someone please explain what this is, and how done. I shoot lead from a G19 but manage to keep it clean. Am always looking to improve.

The easiest way I have found to do it:
1. purchase some cerrosafe at midwayusa. (you can use soft lead, but this is much easier.) http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=462291

2. plug your barrel with a paper towel past a certain point. When casting from the chamber end I normall plug about an inch to an inch and a half in front of the chamber.

3. heat the cerrosafe. It has a very low melting point (@ 158-190 degrees). Note: if you get it all jacked up in a rifle action or something you can submerse your action in boiling water to get it out:whistling:

4. pour

5. 15 minutes later it will shrink up a little. at this time you should push it out.

6. one hour after your pour it will have expanded back out to your original chamber dimensions.

7. measure and record.

You will get something that looks like this (this is the chamber end of a g19):

http://i69.photobucket.com/albums/i54/yammerschooner/g17factorychambercastmeasuredandlab.jpg


This is something you can also do with a soft lead slug. I drilled a hole in a piece of wood to make this one. In order to have a smoother slug I should have scorched the inside of the hole with a torch before pouring in the lead.

Instructions for this method:

1. Make lead slug using soft lead (in this case tape on wheelweights)

2. Pound into area you want to measure

3. Pound out and measure

Here is the chamber of a .40 barrel done with this method:

http://i69.photobucket.com/albums/i54/yammerschooner/chamberslug.jpg

theghostrider
02-25-2008, 12:46
The easiest way I have found to do it:
1. purchase some cerrosafe at midwayusa. (you can use soft lead, but this is much easier.) http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=462291

2. plug your barrel with a paper towel past a certain point. When casting from the chamber end I normall plug about an inch to an inch and a half in front of the chamber.

3. heat the cerrosafe. It has a very low melting point (@ 158-190 degrees). Note: if you get it all jacked up in a rifle action or something you can submerse your action in boiling water to get it out:whistling:

4. pour

5. 15 minutes later it will shrink up a little. at this time you should push it out.

6. one hour after your pour it will have expanded back out to your original chamber dimensions.

7. measure and record.

You will get something that looks like this (this is the chamber end of a g19):



This is something you can also do with a soft lead slug. I drilled a hole in a piece of wood to make this one. In order to have a smoother slug I should have scorched the inside of the hole with a torch before pouring in the lead.

Instructions for this method:

1. Make lead slug using soft lead (in this case tape on wheelweights)

2. Pound into area you want to measure

3. Pound out and measure

Here is the chamber of a .40 barrel done with this method:I appreciate the instructions and hints, but what is the purpose? Is it just to measure the inner dimensions of the barrel and chamber? Is that what it means to "slug the barrel"?

The phraseology is completely new to me.

yammerschooner
02-25-2008, 13:07
The bottom one was done when I was having some issues with a barrel and needed some way to compare how two barrels were cut.

The top one was done when another gent asked for information on issues he was having with one of his barrels and needed a comparison.

Yep, you are just measuring inner dimensions.

theghostrider
02-25-2008, 15:09
The bottom one was done when I was having some issues with a barrel and needed some way to compare how two barrels were cut.

The top one was done when another gent asked for information on issues he was having with one of his barrels and needed a comparison.

Yep, you are just measuring inner dimensions.
How does that prevent leading? Is it so one can properly size the bullets?

yammerschooner
02-25-2008, 15:25
Yep, it can be used to know what bullets should be sized at. A bullet that is too small will allow gas to go by, which will contribute to leading.

When I was doing the above my concern was more with freebore measurements and feeding issues.

theghostrider
02-25-2008, 18:37
Thanks.

MakeMineaP99
02-25-2008, 19:12
Yammer is the man when it comes to running lead. All I know is the physics.

Beware Owner
02-29-2008, 16:49
Read to find thy self improved.

Search the web for the topic and you will find pages of evidence that speaks for itself. Solids are very slow moving liquids.

:whistling:

Now that's a concept worth considering.

SCmasterblaster
02-29-2008, 17:08
And quite successfully.

I cast my own 155fr LRN from a six-cavity Lee mold, and use the Lee liq alox lube.

I load them ahead of 2.7 gr HTG, and at a mere 800 FPS, there is NO leading.

Beware Owner
02-29-2008, 17:09
And quite successfully.

I cast my own 155fr LRN from a six-cavity Lee mold, and use the Lee liq alox lube.

I load them ahead of 2.7 gr HTG, and at a mere 800 FPS, there is NO leading.

Do Lee molds last much? How much would you say is there "life span"?

yammerschooner
02-29-2008, 17:28
Do Lee molds last much? How much would you say is there "life span"?


I figure I have a minimum of 40 to 50 k on my lee mold for .40. It has quite a bit of use left in it if I don't drop it and smack the edge of a cavity on something.

SCmasterblaster
02-29-2008, 18:30
Do Lee molds last much? How much would you say is there "life span"?


Three years of heavy winter usage, and going strong.

Beware Owner
03-01-2008, 09:21
I figure I have a minimum of 40 to 50 k on my lee mold for .40. It has quite a bit of use left in it if I don't drop it and smack the edge of a cavity on something.

Are these the aluminum moulds? If so, then I'll save more money than moving to Geico!

yammerschooner
03-01-2008, 09:36
Yep. Aluminum.

and that estimation on numbers is probably very, very, low.

Beware Owner
03-01-2008, 11:56
Yep. Aluminum.

and that estimation on numbers is probably very, very, low.

You just made my day. I want to get a Bar Sto or Lone Wolf ported .357 Sig barrel and I want to shoot lotsa lotsa lead through it. With a 6 cavity mould, a 10 or 20 lb bottom pour pot, and a Lee Lubrisizer I'll be good to go for a while, right?

Beware Owner
03-01-2008, 12:02
And quite successfully.

I cast my own 155fr LRN from a six-cavity Lee mold, and use the Lee liq alox lube.

I load them ahead of 2.7 gr HTG, and at a mere 800 FPS, there is NO leading.

Is that .45?

yammerschooner
03-01-2008, 22:05
You just made my day. I want to get a Bar Sto or Lone Wolf ported .357 Sig barrel and I want to shoot lotsa lotsa lead through it. With a 6 cavity mould, a 10 or 20 lb bottom pour pot, and a Lee Lubrisizer I'll be good to go for a while, right?

go with the 20 lb pot.

Rich Thompson
03-02-2008, 00:26
We all have things to learn and opinions to share. I am going to add my two cents worth in a friendly manner. I agree that a barrel expands in diameter behind the bullet as it is being fired. It is , however, a very small amount and the thicker the barrel the less the effect. A barrel also stretches as the high pressure is trying to push the blockage,(the bullet) out of the way. There is extremely high pressure on one side of the bullet and atmospheric pressure on the other this causes an expansion in length and diameter. After the bullet leaves, the "springyness" of the steel returns it back to its original dimensions. It all happens so fast it is more like a vibration. Steel also has pores in it. A well seasoned and conditioned barrel has fewer and smaller pores. Although it has pores, it is not like a sponge that with keep "absorbing" lead until it ruptures. I do agree that a conical shaped jacketed bullet cannot scrape lead from a barrel but I think it smears the lead into a thin film where it can then peal or flake away during the shoot. At a microscopic level I see how the harder copper could "iron" the lead into the pores of the steel. I guess I stand in the middle on that one but I believe if the gentleman says his barrel cleans easier by what he's doing he would know. I guess we all could use a refresher in physics I could be all wrong. These are all just theories anyway. On a related subject I am very interested in electroplating copper on cast bullets. I figure there will be much research and anyone that shares this interest and has knowledge I would truly appreciate it. I found a metal finish web site that some one spoke of a "carousel" that was for plating bullets that boasted of a .01" thickness but the thread lacked detailled specific info. I need to know exact wall thickness so I can get the right mold and, do I swage the bullet afterwards etc. If this process can be as easy as throwing some pennies in a solution with some cast bullets and striking them in swage the next morning wouldn't that be great?

Beware Owner
03-02-2008, 21:39
go with the 20 lb pot.

Yes, sir. Hey, what do I do with the sprue that falls in the bucket? Or should I drop that elsewhere to avoid that problem altogether?

outlaw1niner
03-03-2008, 06:11
I have a few questions about lead bullets in Glocks. I just bought a G21SF and I have a large quantity of lead bullet reloads on hand. I loaded them for use in my Colt 1911 and I am wondering if they'd be OK to use in my new Glock.

It is a pretty mild load consisting of 230gr Oregon Trail Laser Cast bullets loaded over 4.2 grains of Bullseye. This load has not given me any problems with leading in my 1911.

Anybody use these same bullets in their Glock .45's? What do you all think?

Thank you.

Apocalypse_Now
07-10-2008, 18:39
Do Lee molds last much? How much would you say is there "life span"?

The 5 cavity versions are really beefy and sturdy, they are what I prefer.. but even the 2 cavity are a great deal. Haven't worn one out, yet

DanaT
07-10-2008, 21:34
Ya. And my BMW says premium fuel only. Guess what! It also runs on 87 octane with no problem and that after about 10 years. Don't believe everything the manufacturers tell you.

It might run on low grade fuel, but guess what, there is a knock sensor to retard timing when it senses knock. This reduces power. So, yes, it RUNS on low grade fuel but it doesnt perform to its best potential. Me, personally I want my car to run on E85 at 105 octane equivalent because it performs better..

-Dana

DanaT
07-10-2008, 21:38
Like I said this is one for the Mythbusters. I'll it when I see it; say a caliper on a barrel expand after firing (although lateral vibration may though this off), or or if it's on a high speed camera you might be able to see.

Sig, is there scientific proof of this or were you just taught this by someone? Just wondering, not meant to be an attack on you!

I hope I am not starting WWIII with my humble opinion.
I still agree that a copper jacketed bullet shot after lead is not going to magically clean the barrel. That is what bore snakes and brushes are for.

Yes. There is scientific proof. Its called a strain gauge. 1st year mechanical engineers learn about hoop stresses in pressure vessels. A barrel is just a thick pressure vessal with a variable end. Google hoop stress equation and you will find how to calculate it.

-Dana

DanaT
07-10-2008, 21:45
[QUOTE=4eyes;9880405]Here is another way to explain the phenomena: Think of MMAP99 sitting on the toilet. No strain--orifice remains closed. Introduce strain in the form of extrudate--orifice starts to open (bullet leaves chamber). Continued extrudate, continued strain, orifice expanded to nearly full open (bullet in mid bore).Relax strain, slow extrudate, orifice reduces in size (bullet near end of barrel). Stop strain, no extrudate, orifice slams closed (bullet clears bore).

Audible bang in bathroom. No strain and orifice resumes near normal size after cleaning.

;) :whistling:




Excellent analysis, Bob. Did you have to pick on me? ;)

Now what happens when MMAP99 takes up muzzle loading??? I think the bullets remains out of the bore and then the bullet is put into the bore......

-Dana

DanaT
07-10-2008, 21:50
On a related subject I am very interested in electroplating copper on cast bullets. I figure there will be much research and anyone that shares this interest and has knowledge I would truly appreciate it. I found a metal finish web site that some one spoke of a "carousel" that was for plating bullets that boasted of a .01" thickness but the thread lacked detailled specific info. I need to know exact wall thickness so I can get the right mold and, do I swage the bullet afterwards etc. If this process can be as easy as throwing some pennies in a solution with some cast bullets and striking them in swage the next morning wouldn't that be great?

Plating is typically not something that you can do at home. It takes special equipment and can be very hazardous. For exmaple, some plaing operations need flourinate acids to activate the base metal (Hydroflouric acid or a mixture using ABF).

Plating onto lead is also difficult.

-Dana

Beware Owner
07-10-2008, 23:20
I got me some lead bullets. Is the bore snake the best way to go to keep my baby clean? How much is too much to pay for one?

CanyonMan
07-12-2008, 11:01
If you will use bullets with a BHN (hardness), of 20/21, You won't foul the Glock barrel hardly at all, even with a good deal of shooting. I reload for everything I got. I reload some very hot rounds in my G20. I use Cast bullets from Cast Performance Bullets. http://www.castperformance.com/StoreFront.bok

I have fired tons (so to speak), through the Glock barrel at one setting, and simply swabbed the barrel out with a copper brush afterwards. (no elbow grease needed), just took a minute.

You get the fouling with the softer lead.... Try lead at the BHN of 20/21, I use this harness in all my Glocks and Rugers, no problems.

Beartooth Bullets are really good as well... http://www.beartoothbullets.com/



Good luck.

CM

Beware Owner
07-12-2008, 12:10
If you will use bullets with a BHN (hardness), of 20/21, You won't foul the Glock barrel hardly at all, even with a good deal of shooting. I reload for everything I got. I reload some very hot rounds in my G20. I use Cast bullets from Cast Performance Bullets. http://www.castperformance.com/StoreFront.bok

I have fired tons (so to speak), through the Glock barrel at one setting, and simply swabbed the barrel out with a copper brush afterwards. (no elbow grease needed), just took a minute.

You get the fouling with the softer lead.... Try lead at the BHN of 20/21, I use this harness in all my Glocks and Rugers, no problems.

Beartooth Bullets are really good as well... http://www.beartoothbullets.com/



Good luck.

CM

How would you say 16-17 BHN does on factory Glock barrels?

Apocalypse_Now
07-12-2008, 19:35
If you will use bullets with a BHN (hardness), of 20/21, You won't foul the Glock barrel hardly at all, even with a good deal of shooting. I reload for everything I got. I reload some very hot rounds in my G20. I use Cast bullets from Cast Performance Bullets. http://www.castperformance.com/StoreFront.bok

I have fired tons (so to speak), through the Glock barrel at one setting, and simply swabbed the barrel out with a copper brush afterwards. (no elbow grease needed), just took a minute.

You get the fouling with the softer lead.... Try lead at the BHN of 20/21, I use this harness in all my Glocks and Rugers, no problems.

Beartooth Bullets are really good as well... http://www.beartoothbullets.com/



Good luck.

CM

Thank you for a logical answer to my question. I cast my own hard-cast linotype bullets, quench them in a bucket of cold water as they come out of the mold, and then lube them well (Lee tumble lube design molds and lube) and in my other pistols I have never had a leading problem that couldn't be easily cleaned out after some jacketed bullets at the end of each shooting session, and then a few passes with a lead remover tool, if required

CanyonMan
07-12-2008, 21:46
How would you say 16-17 BHN does on factory Glock barrels?




It is just a fact of life... softer lead fould barrels bad. That being said...

I have not used such a soft bullet in a Glock barrel..... But, for the 35+ years I've reloaded for the big bore Rugers, and other revolvers/and semi's I "can" tell you they "do" foul the barrel and need more attension to cleaning, and more work.

The links I gave to "Cast Performance, and Beartooth," are both very reliable bullets, and i have "never had a fouling problem," with tons of lead going through everything I shoot. BHN 20/21

The accuracy is excellent, even out of my G20 at some very loooong range shooting. Come home run a little solvent through, with a copper brush, couple rags.... Put 'er up ! ;)

HTH's


CM

CanyonMan
07-12-2008, 22:09
Thank you for a logical answer to my question. I cast my own hard-cast linotype bullets, quench them in a bucket of cold water as they come out of the mold, and then lube them well (Lee tumble lube design molds and lube) and in my other pistols I have never had a leading problem that couldn't be easily cleaned out after some jacketed bullets at the end of each shooting session, and then a few passes with a lead remover tool, if required


Don't get PO'd at me now, but this is a common misconception with a good deal of shooters. That is , "run a few FMJ, or copper bullets" through "after shooting lead. It is a fact of physics, that the copper bullet only serves to help flatten, or conform the lead previously fired, deeper into the lands.

I have seen this hundreds of times, and had to help countless people get "all the fouling out", who "swore was not there." :supergrin:

That barrel may look nice and shiny, but there is the problem.... The lead has been shined, and folks think it is a clean barrel. Then I can go in there and pull out a truck load of fouling. They go "WOW !" how did I miss that? ha

This method over time, will diminish accuracy, and cause some mighty hard build up and require tremendous elbow grease to get truly clean.

We have given barrels, what I call a " colonoscopy." using fiber light wire to run down the tube and view it on a TV monitor in the shop, It magnifies everything about 10X. You would not believe the things we have found. From unseen "before" tool marks, to fire checked barrels, to tons of fouling, from soft lead, that the person thought was a shiny barrel, either from poor clening, or the the heat of copper follow up shots, pressing the lead down as to look like part of the barrel.

You, in your bullet making process, may be producing a BHN of 20/21, and not know it, and therefore your follw up shots with copper have not caused a problem, cause there was none to begin with. But I certainly would determine the BHN of my lead, and find out if this is indeed the case, OR if you are just shining up the lead shooting copper through.

BTW, it is just this side of impossibe "sometimes" to tell even with a bore light, that the lead build up is there, because it has so much become "one" with the barrel, and the shine, that all looks well.

Run a very strong amonia (sp) base cleaner through the barrel, and let it soak for a few hours, plugging the bore and breech ends. Then use a slighty oversized copper brush, and you may well be shocked to see how dirty that barrel really is, again, barring that your being blessed with a 20/21 BHN and don't know it. ;)


Good shoting.


CanyonMan

Beware Owner
07-14-2008, 07:02
The 5 cavity versions are really beefy and sturdy, they are what I prefer.. but even the 2 cavity are a great deal. Haven't worn one out, yet

Good. I'll keep the five cavity molds as a second resource after the six. Production, baby, production!

It is just a fact of life... softer lead fould barrels bad. That being said...

I have not used such a soft bullet in a Glock barrel..... But, for the 35+ years I've reloaded for the big bore Rugers, and other revolvers/and semi's I "can" tell you they "do" foul the barrel and need more attension to cleaning, and more work.

The links I gave to "Cast Performance, and Beartooth," are both very reliable bullets, and i have "never had a fouling problem," with tons of lead going through everything I shoot. BHN 20/21

The accuracy is excellent, even out of my G20 at some very loooong range shooting. Come home run a little solvent through, with a copper brush, couple rags.... Put 'er up ! ;)

HTH's


CM

Understood. At this time I'm not sure what is soft, not soft enough, and too soft. If I had a chart that would tell me what BHN is best when shot a which speed, that would make my life easier. Right now I have some plated bullets and a good number of lead which are 16-17 BHN. I haven't loaded a single bullet I've shot, but yesterday I finally got around to sizing and priming all my cases with the Federal 100 primers, about 308 (approx. 180 Starline, 80 Speer, the rest mixed) cases in all. I know, not much, but I'm just starting. Today I'm going to make my test ammo, 10 rounds per charge, to be shot in 5shot groups to be measured, will test the plateds and the lead. I'm going to start with 11.7 of #9 and take it up on .1 increments, got me a Bore Snake on the weekend. If I know what velocity the lead starts to foul, then that's my max for that particular load/BHN combination.

steelhorses
02-06-2009, 08:25
Good. I'll keep the five cavity molds as a second resource after the six. Production, baby, production!

Understood. At this time I'm not sure what is soft, not soft enough, and too soft. If I had a chart that would tell me what BHN is best when shot a which speed, that would make my life easier. Right now I have some plated bullets and a good number of lead which are 16-17 BHN. I haven't loaded a single bullet I've shot, but yesterday I finally got around to sizing and priming all my cases with the Federal 100 primers, about 308 (approx. 180 Starline, 80 Speer, the rest mixed) cases in all. I know, not much, but I'm just starting. Today I'm going to make my test ammo, 10 rounds per charge, to be shot in 5shot groups to be measured, will test the plateds and the lead. I'm going to start with 11.7 of #9 and take it up on .1 increments, got me a Bore Snake on the weekend. If I know what velocity the lead starts to foul, then that's my max for that particular load/BHN combination.

Reviving an old thread. Did you ever find out what velocity leading occured?

How do you determine what BHN number your lead is?

dudel
02-06-2009, 09:39
I suspect the leading might be more of a problem in a new barrel, than in one that has had a couple hundred jacketed rounds put through it. The break in would tend to remove some of the rougher spots that could increase leading.

My 15 year old G17 has had many jacketed rounds through it, and it takes hard lead bullets ok if I keep the speed low. Despite that, I got a Lone Wolf barrel for it specifically for lead rounds. It shoots great with lead, and for $99 from Dillon, it's great.

The new G26 leaded badly after a few lead rounds. I'm keeping it on a jacketed/plated diet for a while.

One thing with lead (hard or soft), is to keep the speed down compared to jacketed rounds. Heck, even plated rounds should not be pushed as fast as you jacketed rounds.

Don

dudel
02-06-2009, 09:47
That barrel may look nice and shiny, but there is the problem.... The lead has been shined, and folks think it is a clean barrel. Then I can go in there and pull out a truck load of fouling. They go "WOW !" how did I miss that? haCanyonMan

+1 CanyonMan makes a good point. I had heard the old line about shooting FMJ after lead, and wanted to test it out. I cleaned till I saw the shine in the barrel (didn't realize I had just shined the lead :shocked:) and the patches came out clean.

Then I took my Foul Out to see how well I had cleaned it. There was plenty of lead collected on the rod! Well maybe the lead was there before. So now I had a clean barrel. Shot some more lead (number escapes me now) followed by 5 FMJ. Cleaned with brush and Hoppes, till barrel was shiney and the patches clean. Once again, the Foul Out had lead on collected on the rod.

Just my $.02. CanyonMan's explanation makes sense based on what I saw.

Don

Beware Owner
02-06-2009, 10:24
Reviving an old thread. Did you ever find out what velocity leading occured?

How do you determine what BHN number your lead is?

I found out they're 15/16 BHN, and was told to keep velocities about 1100fps. What I did was bring down the charge to 10.3gr and all my problems were solved. By the book, the starting load was 11.7gr, but I was told that the G32 would cycle well at 10.3gr, so I tested that too. I saw no leading until I got closer to the 11.0gr mark.

kilika1000
07-25-2009, 01:22
so does shooting lead bullets through your stock glock barrel actually harm it anyway. i mean it sounds like all you have to do is keep it clean while you shoot it. i mean if you keep it clean, then scrub it out and clean your barrel after your done shooting will your barrel be fine, or overtime will it damage it. I mean the last thing i want to do is damage my barrel, but i don't want to go spend a 100 bucks on a barrel that i don't need you know. i can keep my stock barrel clean if thats the case.

voodoomanx
07-25-2009, 07:06
so does shooting lead bullets through your stock glock barrel actually harm it anyway. i mean it sounds like all you have to do is keep it clean while you shoot it. i mean if you keep it clean, then scrub it out and clean your barrel after your done shooting will your barrel be fine, or overtime will it damage it. I mean the last thing i want to do is damage my barrel, but i don't want to go spend a 100 bucks on a barrel that i don't need you know. i can keep my stock barrel clean if thats the case.

Did you read the four pages leading up to this?

It depends.

SCmasterblaster
07-25-2009, 19:07
Do Lee molds last much? How much would you say is there "life span"?

I have been using my Lee AL molds for years and years, with very little wear.

I am happy to have a place to say this fact.

dla
07-25-2009, 23:25
I just ran 100 185gr lswc reloads through a new, stock G21 - no leading. These loads were running right at 1100fps. These were mid-range hardness bullets - nothing special. They were pushed by AA#5.

marcclarke
04-26-2010, 22:51
Guys, I'm with you on this, but aren't we missing an important part here? What about "cycles to failure"? We can stress metals below yield but the cycles to failure is to me, what's really important here.
If I'm wrong, clear me up.
Bronson7
You are completely correct. The process to which you refer is called "metal fatigue".

marcclarke
04-26-2010, 23:31
This sounds like a case for Mythbusters! I find it hard to believe that a barrel actually "expands." I always thought that the bullet was deformed or formed to match the rifling. Now, I guess if the bullet is hard enough and the barrel is thin enough, a little expanding might take place. But what about say a 38 with a 3/8" thick barrel? That baby is not going to expand. Or how about a SS bull barrel on a 10/22? That bullet is not expanding the barrel in the least. The heat is coming from the friction, not expansion.

You have part of the equation here, but not all of it. The burning powder inside the barrel exerts pressure (pounds per square inch, or in the case of bullets, Copper Units of Pressure). The pressure exerts force on the metal of the barrel. The metal of the barrel deforms (slightly) from the force exerted on it by the burning powder. Many reloading manuals specify the measured pressure of their loads, either in psi or CUP.

The pressure peak inside the barrel is rapid and transient, so it is a wee bit difficult to measure barrel expansion unless one uses high speed photography and/or laser interferometery. However, it is very straightforward to take a tube of metal, seal one end, fill it with water, and put a 100 ton hydraulic press (or larger) to work pushing a copper plug to pressurize the water. Then one can use a standard measuring tool to measure how much the outside of the cylinder expands. These measurements have been done since the days of James Watt and the first steam engines at the beginning of the Industrial Revolution. The numbers have been published in engineering handbooks for more than a century.

Every time a new steel alloy is invented, the foundry measures the deformation characteristics and publishes them. Independent laboratories confirm them.

Yes, a the pressure of the powder charge behind the bullet does make the barrel bulge, ever-so-slightly. Off the top of my head, and without hitting any of my reference books, I'll guess maybe a few ten-thousandths of an inch. If it is important to you to be more accurate I'm sure you can find numbers on the web with some Google searches.

No call to Myth Busters needed. Engineers have known all about cylinders (pipes) expanding from internal pressure (steam) since the early days of wood-burning steam railroad locomotives.

Firearms manufacturers have known about the issue for literally centuries.

Yes, thicker barrels do result in less deformation. Properly alloyed steel is very strong--have you ever seen the thickness of the internal barrel in an old Dan Wesson revolver? It does not take much steel to hold in the pressure of a revolver round, even a Magnum.

In a semi-automatic pistol with a partially unsupported chamber, the brass case is the weakest link when the pressure starts to go too high. Thus, we hear about the KaBoom! phenomenon where the side of the rear of the case blows out. We don't hear about barrels blowing out. In revolvers we see pictures of the chamber walls (the thinnest metal) blowing out, and sometimes the top strap breaking under the force of the over-pressure round.

We see barrels blowing when there is some sort of obstruction in the muzzle (mud, dirt, leaves, even snow) or in the bore (a cleaning patch most commonly).

Sorry about the long post. I hope I saved you a call to Myth Busters. :whistling:

marcclarke
04-26-2010, 23:44
No I am not an engineer, but with your reasoning taken to the extreme, means that when I push my plastic Glock cleaning brush through my barrel (it is a larger diameter than the inside of the barrel and will produce an outward force), even this force is going to expand the barrel, at least to some microscopic degree. How about a wax or rubber bullet. Will that also expand the barrel? I say no. And neither will a soft bullet, say a lead one at low velocities. Rather the barrel will deform the bullet to its dimensions like a die on brass.

All I am saying is that there has to be some allowance for hardness of the bullet, velocity, and the thickness of the barrel before we assume that the barrel will "always" expand.

You are correct. There is a minimum pressure required before there is any observable deformation of the barrel. A plastic bore brush won't apply enough pressure on the inside of the barrel to reach that minimum required force. The bristles of the plastic bore brush will deform--the barrel won't.

As to wax or rubber bullets, it isn't so much the bullet that expands the barrel, it is the pressure of the gas behind the bullet inside the barrel. The maximum pressure (PSI or CUP) reached inside the barrel is a function of the burn rate of the powder, the burn rate of the primer, the volume of the case, the inertia of the bullet (heavier bullets accelerate more slowly at the same pressure than lighter bullets do), the material from which the bullet is made, the material from which the bullet's jacket is made (if there is a jacket), and the retarding friction of the bullet against the inner walls of the barrel. The degree of smoothness of the barrel's inner wall also plays a minor role.

stengun
04-30-2010, 22:55
Howdy,



an old wive's tale




Paul

marcclarke
05-01-2010, 13:50
I appreciate the instructions and hints, but what is the purpose? Is it just to measure the inner dimensions of the barrel and chamber?
Yes.

Is that what it means to "slug the barrel"?
Yes.