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aarolar
12-12-2011, 19:30
I have been doing a lot of research lately and I am thinking very hard about setting my glock up to run 460 Rowland. From my research the Rowland has the exact same case capacity the only reason it's longer is to prevent someone from loading a hot ass case into a non compatable firearm. Please read this article it goes over it all very well.

http://www.realguns.com/archives/106.htm

From what is said here the Rowland runs at 38k psi which is right on par with most modern pistol rounds like 40S&W, 10MM, 357Sig ect. and if a glock can handle these rounds why can't it handle the Rowland? The way I am seeing it standard ACP is way neutered simply because that is where it started and because there are 100+ year old guns chambered for ACP. They can't really step it up because these older guns couldn't handle these pressures.

My plans of now are to start with super and very carefully and cautiously work up and see what happens. I am going to start with a KKM standard length barrel with a SS guiderod and 22lb spring. Since super brass is so damn hard to find I am going to order Rowland brass and just trim it down to standard length and work with that. What I am looking for from yall is someone to question my thought patterns and keep me on my toes I am really convinced there is so much more to be gained from the 45 platform and I plan to test my theorys, so feel free to add whatever you feel is relevant. All I ask is that you have an open mind on the subject and keep the discussion on topic...

Bushflyr
12-13-2011, 19:01
Looks like a good plan. You'll probably get better info over in the reloading forum. According to that site you'd probably be better off searching for the Super brass due to the thicker web and base. It should be stronger. Disregard the max OAL and load as long as you can get away with in your gun.

Great project. Wear gloves and a face shield. :supergrin:

And read this thread http://www.glocktalk.com/forums/showthread.php?t=1363112

aarolar
12-14-2011, 15:46
Looks like a good plan. You'll probably get better info over in the reloading forum. According to that site you'd probably be better off searching for the Super brass due to the thicker web and base. It should be stronger. Disregard the max OAL and load as long as you can get away with in your gun.

Great project. Wear gloves and a face shield. :supergrin:

And read this thread http://www.glocktalk.com/forums/showthread.php?t=1363112

Already seen it trust me I have read most everything avaliable on this subject. I emailed Jonny Rowland monday and it turns out that he actually has kits for a glock ready to ship, the kit contains a barrel, guide rod and spring for 319 bucks +shipping. I have a feeling it's a rip off because I can buy a lone wolf barrel, guide rod, and spring for much less that what he's offering. I think Im gonna pass on his kit for now and progress along the path I already started on.

speedweapon
12-15-2011, 13:50
What kind of front sight will you be using?

Just wondering.......

RWBlue
12-15-2011, 14:42
Do a search on my user name and 45Super I try to comment on anyone who plans on making the change.

If I understand it correctly you will try to push the round hard to very hard, in doing this you will kill your gun. Not with a Kaboom, but beating the slide against the frame. I suggest that you look into getting a barrel with a compensator. If you don't want the compensator, just don't push the round that hard.

I would also suggest contacting star brass and letting them know you want 45Super brass. If enough people make the request, then everyone will have more 45Super brass to work with.

Jim Watson
12-15-2011, 17:50
Since super brass is so damn hard to find I am going to order Rowland brass and just trim it down to standard length and work with that.

Does this mean you will overload ammunition at standard ACP case and chamber length and CALL it a Rowland? Scary.

aarolar
12-15-2011, 18:59
Does this mean you will overload ammunition at standard ACP case and chamber length and CALL it a Rowland? Scary.

That is exactly what the 460 Rowland is the extra length gives absoutely no useful case capacity what so ever. Read the article I posted and you will understand.

aarolar
12-15-2011, 19:02
Do a search on my user name and 45Super I try to comment on anyone who plans on making the change.

If I understand it correctly you will try to push the round hard to very hard, in doing this you will kill your gun. Not with a Kaboom, but beating the slide against the frame. I suggest that you look into getting a barrel with a compensator. If you don't want the compensator, just don't push the round that hard.

I would also suggest contacting star brass and letting them know you want 45Super brass. If enough people make the request, then everyone will have more 45Super brass to work with.

I have come to terms with this and realize I more than likely won't be able to push it quite as far without a comp I may still get a threaded barrel and try a comp just to see. One thing that keeps coming back to mind is that guys are running 10mm rounds with as much if not more ME everyday with no comp how come those guns arent coming apart left and right? Not saying your wrong just something else to ponder...

RWBlue
12-15-2011, 20:09
I have come to terms with this and realize I more than likely won't be able to push it quite as far without a comp I may still get a threaded barrel and try a comp just to see. One thing that keeps coming back to mind is that guys are running 10mm rounds with as much if not more ME everyday with no comp how come those guns arent coming apart left and right? Not saying your wrong just something else to ponder...

With a good barrel, you can go beyond 10mm (grs bullet * velocity) before having any case issues.

The comp increases lock time so it reduces the forces on the slide.


Now, me, I don't have a comp per say. I have a suppressor. Normally with a Glock a suppressor needs a LID to operate. With my heavy loads, I didn't need a LID. The gun cycled fine. I beat up my Glock pretty bad as I developed heavy loads. I am not someplace I can continue to work on my balistic studies, so .....no comp, no G20 upper, no G20 upper with 40S&W barrel or 357Sig barrel or .....

DanaT
12-21-2011, 12:30
You guys are missing some basics.


Pressure = pounds / square inch

If you take the square inches out (by multiplying) then you get forceon the slide.

So lets assume 10mm at 37500psi and 45 at 37500psi.

10mm (0.401/2)^2 * pi * 37500 = 4735lbf
45 = (0.451/2)^2 * pi * 37500 = 5990lbf

So, now, the force on the slide, at the same pressure, is 26% higher with a .45 caliber bullet than a 40 caliber bullet (this is 26% more surface area of the bullet).

Later I can post a link (I am not at home) but adding a spring helps slide battering but does not help lock-up. You have a mass spring system. The initial movement of the slide is almost entirely dependant upon mass and not spring. Keep in mind a spring has a force that is measured as "k" meaning that the more the spring is compressed the more force it exerts. This means at the beginning of the cycle, that spring adds much less to the system that when it is compressed. Now to combat this, a longerand stiffer spring can be added (this means force is added because the spring is pre-compressed).

The general statement is force is very high on this combination. It must be accounted for.

I would want a 10mm slide (for the additional mass) to start making this pistol.

-Dana

Bushflyr
12-21-2011, 13:09
Which is why, as RWBlue posted, the Rowland sites all say a comp is required. The force on the comp delays unlocking. You could start with a 10mm slide, but I don't think the .45 barrel wit fit through the hole in the end. I haven't measured though.

DanaT
12-21-2011, 20:33
Which is why, as RWBlue posted, the Rowland sites all say a comp is required. The force on the comp delays unlocking. You could start with a 10mm slide, but I don't think the .45 barrel wit fit through the hole in the end. I haven't measured though.

I doubt it would fit. Thats why I said start with a 10mm slide. By "start" I meant as a starting point for modification.

I am not seeing in the FBD how a compensator at the end of the barrel delays unlocking.

Movement starts when force starts which is when ignition of the powder starts.

This is the book that I was talking about that explains locking time well as well as cycle rate (this is the mass-spring system). It talks about automatic weapons, but the same formulas apply to semi-auto although with a semi you don't have as critical of rounds per minute (cycle rate).

[url]http://www.worldcat.org/title/engineering-design-handbook-gun-series-automatic-weapons-1970/oclc/506047197[url]

-Dana

Bushflyr
12-21-2011, 20:50
The forward push of the gas on the baffles in the comp provides a pretty significant amount of forward force on the barrel/slide unit thus delaying unlocking and reducing slide velocity; Especially in the case of a high pressure round like the 460.

I've actually had guns where the comp was so effective it wouldn't cycle without a lighter spring and one where it wouldn't cycle with the comp on at all no matter how light a spring I put in it.

ckrockets
12-21-2011, 21:06
That is exactly what the 460 Rowland is the extra length gives absoutely no useful case capacity what so ever. Read the article I posted and you will understand.

My understanding is the 460 Rowland brass is stronger then normal 45 ACP brass so you can run it at a higher pressure and the added length is so you can't shoot it out just any pistol chambered in 45 ACP.

When I say stronger I believe it has a thicker webbing and heat treated differently.

Call Starline they can probably tell you exactly what they do differently.

DanaT
12-21-2011, 22:32
I am just not seeing how the compensator will help much.

Just putting some qucik data into quickload, it gives a pressure/distance curve.

http://i755.photobucket.com/albums/xx196/ddt951t/460.jpg

Pmax is reached in the 1st half inch of bullet travel. By the time the bullet hits the compensators the pressure is down to around 5000psi.

Now, assuming that the compensators are cut at a 45 degree angle, that means that only 70% of the gas force is applied opposite to the bullet travel direction. Moreover to keep it locked that 45 degrees must be pointing towards the shooter. Most likely the venting will be straigt up to reduce muzzle rise and have very little effect on lockup.

I suspect that the compensator that was mentioned in the previous post that the gun would not cycle correct when attached may have had more to due with weight than anything.

-Dana

RWBlue
12-21-2011, 22:58
10mm (0.401/2)^2 * pi * 37500 = 4735lbf
45 = (0.451/2)^2 * pi * 37500 = 5990lbf

So, now, the force on the slide, at the same pressure, is 26% higher with a .45 caliber bullet than a 40 caliber bullet (this is 26% more surface area of the bullet).


You are measuring the wrong end of the cartridge.

RWBlue
12-21-2011, 23:02
I doubt it would fit. Thats why I said start with a 10mm slide. By "start" I meant as a starting point for modification.

I am not seeing in the FBD how a compensator at the end of the barrel delays unlocking.

Movement starts when force starts which is when ignition of the powder starts.

This is the book that I was talking about that explains locking time well as well as cycle rate (this is the mass-spring system). It talks about automatic weapons, but the same formulas apply to semi-auto although with a semi you don't have as critical of rounds per minute (cycle rate).

[url]http://www.worldcat.org/title/engineering-design-handbook-gun-series-automatic-weapons-1970/oclc/506047197[url]

-Dana

The book (or your understanding of the book) is not correct. Put your thumb behind the slide and the slide doesn't move.

RWBlue
12-21-2011, 23:05
My understanding is the 460 Rowland brass is stronger then normal 45 ACP brass so you can run it at a higher pressure and the added length is so you can't shoot it out just any pistol chambered in 45 ACP.

When I say stronger I believe it has a thicker webbing and heat treated differently.

Call Starline they can probably tell you exactly what they do differently.

Starline would not tell me crap when I called them years ago.

What I can tell you is 45ACP brass is not all the same. 45Super brass is not the same as 45ACP. I believe 45Super is stronger than 45ACP.

If you are using an after market barrel with good support and not trying to max out the cartridge, I am not sure if it makes a difference with some 45ACP brass.

RWBlue
12-21-2011, 23:11
I am just not seeing how the compensator will help much.

Just putting some qucik data into quickload, it gives a pressure/distance curve.

http://i755.photobucket.com/albums/xx196/ddt951t/460.jpg

Pmax is reached in the 1st half inch of bullet travel. By the time the bullet hits the compensators the pressure is down to around 5000psi.

Now, assuming that the compensators are cut at a 45 degree angle, that means that only 70% of the gas force is applied opposite to the bullet travel direction. Moreover to keep it locked that 45 degrees must be pointing towards the shooter. Most likely the venting will be straigt up to reduce muzzle rise and have very little effect on lockup.

I suspect that the compensator that was mentioned in the previous post that the gun would not cycle correct when attached may have had more to due with weight than anything.

-Dana

I don't think it takes much force to keep a Glock locked up. Put your thumb behind the slide and watch the gun not cycle.

DanaT
12-21-2011, 23:33
I don't think it takes much force to keep a Glock locked up. Put your thumb behind the slide and watch the gun not cycle.

It is relative.

The mass of a G21 slide/barrel/spring (the moving components) is 600grams. The G20 is 654grams.

To put those number in perspective that is 1.32 pounds and 1.44 pounds respectively. We are not talking large forces to resist movement due to slide mass.

Think about these forces. It is easy to exert 1 pound with a finger. A 5 pound trigger is glock standard. You can easily apply that with your thumb.

Just some quick (ok, not so quick but done earlier so now quick) indicate that to achieve the timing/lockup similar to a stock glock, a 460 Rowland at 1200ft/sec with a 230gr bullet built using a 654gram slide, needs about a 36 pound spring.

-Dana

RWBlue
12-22-2011, 10:30
It is relative.

The mass of a G21 slide/barrel/spring (the moving components) is 600grams. The G20 is 654grams.

To put those number in perspective that is 1.32 pounds and 1.44 pounds respectively. We are not talking large forces to resist movement due to slide mass.

Think about these forces. It is easy to exert 1 pound with a finger. A 5 pound trigger is glock standard. You can easily apply that with your thumb.

Just some quick (ok, not so quick but done earlier so now quick) indicate that to achieve the timing/lockup similar to a stock glock, a 460 Rowland at 1200ft/sec with a 230gr bullet built using a 654gram slide, needs about a 36 pound spring.

-Dana

You probably have a better engineering background than I do since you keep using the numbers. I just know what I know from practical experience.

Here are some other things to think about.
The G20 slide would need to have a larger hole for the barrel and a larger breach for the 45ACP head to fit in. I don't think I would gain much weight after I mill the slide for the changes.

The 45ACP, 45Super, 45Rowland, 44Auto-mag, 308, 30-06, 270.....use the same shell plate for reloading. I don't know if the rifle cartridges brass (designed for higher pressure) would give an advantage over 45ACP brass or not.

Glocks are built for thousands and thousands of rounds. If I increase the abuse, I expect to reduce the number of rounds the gun will last.

If we increase the weight of the slide it will delay the start of the slide moving by a little (which is good), but we also have to stop the movement and the increased weight will be an issue.

I don't think it takes much to keep the slide in battery, but my guess is once it is out of battery it would be very painful to try to stop the movement in mid action.

So far in my testing the slide, barrel, springs.....have not had any issues, it is the frame battering where I am seeing damage. Adding a disposable buffer could be useful if someone decides to push this concept to the max..

PS> I find the differences in the engineering of the 1911 design vs the Glock design interesting. I am not willing to put my thumb behind the 1911 slide, but it is not an issue with the Glock. I was able to go hotter with a standard Colt barrel than the standard Glock barrel (no comp on either).

Bushflyr
12-22-2011, 11:58
I am just not seeing how the compensator will help much.

Let me preface by saying I know you're very intelligent and I enjoy your posts. You need to step away from the straight numbers and build yourself a couple race guns. It's extremely fun and educational.

By the time the bullet hits the compensators the pressure is down to around 5000psi.

It doesn't really matter what the peak pressure is, even 5kPsi hitting the baffles is a bunch of force.

Now, assuming that the compensators are cut at a 45 degree angle, that means that only 70% of the gas force is applied opposite to the bullet travel direction. Moreover to keep it locked that 45 degrees must be pointing towards the shooter. Most likely the venting will be straigt up to reduce muzzle rise and have very little effect on lockup.

This statement is kind of all wrong. :supergrin: Almost every modern comp is cut at 90*. The only ones I can think of that are back cut are the FSC and some for .50 BMG's. I'm sure there are others, but not in common usage for pistols.

The "to keep it locked..." statement implies that you assume the recoil counteraction comes from the "rocket effect" (not exactly sure what to call it.) similar to porting. That isn't the case. A comp works off of the forward push of the gas hitting a flat plate and being redirected 90*, although that is tuned somewhat by the direction of venting.

I suspect that the compensator that was mentioned in the previous post that the gun would not cycle correct when attached may have had more to due with weight than anything.

No. Nothing to do with weight, it wouldn't cycle upside down either. It had everything to do with the compensator taking too much energy out of the system (and leverage :rofl:). I could have gotten it to cycle properly, and did, but the required spring was too weak to strip a fresh round off the mag.

ArmyDoc
12-23-2011, 11:16
You probably have a better engineering background than I do since you keep using the numbers. I just know what I know from practical experience.

Here are some other things to think about.
The G20 slide would need to have a larger hole for the barrel and a larger breach for the 45ACP head to fit in. I don't think I would gain much weight after I mill the slide for the changes.



Actually you wouldn't need a larger hole for the barrel, the barrel diameter is the same (see post #27 here: http://glocktalk.com/forums/showthread.php?t=938598&highlight=g21+g20+barrel&page=2)

The issue is the breach face on the G20 is 0.05 inch narrower than on theG21 (0.40 vs 0.45)

Bushflyr
12-23-2011, 11:27
Good find, AD, I just read that entire thread. Very informative and entertaining. :supergrin:

aarolar
12-25-2011, 14:16
Very interesting facts being brought up on both sides, I understand the way pressures work 5psi on a small vessle is not as significant as 5psi on a large vessle ect. My intentions are not to push the gun to failure I am going to VERY carefully and slowly work up my loads and when I begin to get signs of overpressure or get a queezy feeling in my stomach I am quitting. I mainly have a goal in mind and I belive it should be easily reachable judging by what people have done with the 1911 conversions. I have decided to go with a KKM comped barrel and just screw off the comp when shooing lesser than full house loads that way I don't have to listen to it all the time. I'll keep you all updated with what I find I did alittle developement today but the rain has kept me from shooting them much.