AR-15....to crimp, or not to crimp [Archive] - Glock Talk

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utfelon
08-20-2011, 12:12
I have a Stag super varmiter that I'm trying to load for. I'm new to the AR world. I'm loading some 65 gr SGK and not sure if a crimp is the way to go.
Do you crimp some and not others? Do you crimp only one that have a cannular? I load for acc. so no crimp, or crimp for the set back.


I've read both side or the fence and would like some detailed info.

crsuribe
08-20-2011, 13:12
Yeah dude crimp them twice

ColoCG
08-20-2011, 13:59
I have a Stag super varmiter that I'm trying to load for. I'm new to the AR world. I'm loading some 65 gr SGK and not sure if a crimp is the way to go.
Do you crimp some and not others? Do you crimp only one that have a cannular? I load for acc. so no crimp, or crimp for the set back.


I've read both side or the fence and would like some detailed info.



I never crimp my .223 for my AR with hornady .55gr. fmj or sp never had a problem yet. Might depend on your gun. If you do crimp, crimp only bullets with a cannelure unless your using a LFCD for rifle. YMMV.

PCJim
08-20-2011, 16:48
Have to agree with CG. I have used the LFCD and was not greatly impressed. Whether with or without cannelure, nowadays I don't crimp.

Ferdinandd
08-20-2011, 17:23
I asked the same question a while back and received conflicting opinions, but most folks said don't crimp. I was concerned about setback due to recoil. I loaded ammo without crimp. I measured the AOL of the rounds in the magazine as I worked my way through a 30-rounder. I had no detectable change in OAL. That was with 55 grain SP's over H335 of BLC-2.

steve4102
08-20-2011, 22:35
From The Experts at Sierra.

Neck Tension

When we stop to consider the vigorous (read, downright violent) chambering cycle a loaded round endures in a Service Rifle, it becomes pretty clear it suffers abuse that would never happen in a bolt-action. This is simply the nature of the beast. It needs to be dealt with since there is no way around it.

There are two distinctly different forces that need to be considered: those that force the bullet deeper into the case, and those that pull it out of the case. When the round is stripped from the magazine and launched up the feed ramp, any resistance encountered by the bullet risks having it set back deeper into the case. Due to the abrupt stop the cartridge makes when the shoulder slams to a halt against the chamber, inertia dictates that the bullet will continue to move forward. This is exactly the same principle a kinetic bullet puller operates on, and it works within a chamber as well. Some years ago, we decided to examine this phenomenon more closely. During tests here at Sierra’s range, we chambered a variety of factory Match ammunition in an AR-15 rifle. This ammunition was from one of the most popular brands in use today, loaded with Sierra’s 69 grain MatchKing bullet. To conduct the test, we chambered individual rounds by inserting them into the magazines and manually releasing the bolt. We then repeated the tests by loading two rounds into the magazine, chambering and firing the first, and then extracting and measuring the second round. This eliminated any potential variation caused by the difference between a bolt that had been released from an open position (first round in the magazine) and those subsequent rounds that were chambered by the normal semi-automatic operation of the rifle. Measuring the rounds before chambering and then re-measuring after they were carefully extracted resulted in an average increase of three thousandths (0.003") of forward bullet movement. Some individual rounds showed up to seven thousandths (0.007") movement. Please bear in mind that these results were with factory ammunition, normally having a higher bullet pull than handloaded ammunition.

To counteract this tendency, the semi-auto shooter is left with basically two options: applying a crimp or increasing neck tension.

http://www.exteriorballistics.com/reloadbasics/gasgunreload.cfm

utfelon
08-21-2011, 00:20
Thanx Steve good post

EL_NinO619
08-21-2011, 00:51
Light Crimp. Has worked great for me. Did not crimp 55gr sierras and did the set back test, and they moved for sure. not much, but i figure a crimp cant hurt for that crap case that has weak neck tension. Now if your shooting matches with a AR platform you may consider not crimping, but i just plink and have never had any less accurate ammo..

steve4102
08-21-2011, 05:34
I have been doing a lot of load testing in my AR over the past several weeks. One of the tests was crimped loads vs non-crimped loads. Here is one of many targets that showed similar results. The target on the left was a 53gr Sierra Match with no crimp. The target on the right was same load same bullet with a med crimp using the Lee Factory Crimp Die.
http://i2.photobucket.com/albums/y17/steve4102/crimp223.jpg

unclebob
08-21-2011, 08:37
If you want to increase the neck tension of the rifle rounds. Take about .002 off of the resizing button on the decapping rod.
Or use the Redding bushing dies.

Zombie Steve
08-21-2011, 08:52
<--- doesn't crimp for AR.

steve4102
08-22-2011, 06:34
If you want to increase the neck tension of the rifle rounds. Take about .002 off of the resizing button on the decapping rod.
Or use the Redding bushing dies.

I've done that as well. I have several bushings for my 30-06 and 300WSM Redding dies. In my tests, increasing neck tension decreased accuracy while the use of the LFCD increased it, YMMV.

unclebob
08-22-2011, 07:12
If done that as well. I have several bushings for my 30-06 and 300WSM Redding dies. In my tests, increasing neck tension decreased accuracy while the use of the LFCD increased it, YMMV.

Since I never really did get into high power shooting other than getting my feet wet. That was what I was told by many high powder shooters. And not to crimp the rounds. Both .223 and .308.

DoctaGlockta
08-22-2011, 07:29
Light crimp here. Just another stage in the progressive so no big deal to do for me.

nc910
08-22-2011, 15:33
I don't crimp for any of my AR's.

StoneDog
08-22-2011, 15:40
For those of you that don't crimp, have you ever had issues with the bullet falling into the case? I loaded up 50 a while back with no crimp. I accidentally slammed the ammo box on a table and a number of them dropped down into the case... I'm sure I did something else wrong, but I'm thinking the crimp would have prevented this.

nc910
08-22-2011, 15:45
StoneDog:

I've never had any problems. It sounds like you seriously whacked your rounds without realizing it, or you've got neck tensions issues. Out of curiosity, what was the bullet/brass combination and what kind of seating die did you use?

BBJones
08-22-2011, 16:56
No crimp here. I do pay close attention to neck tension. For those you crimp do you also carefully trim all your brass. Crimping without having the same length brass will yield very inconsistent crimps.

The Sierra article was interesting that the OAL was increasing and not decreasing. Which to me is a good thing compared to the chance of the bullet being set back.

jdavionic
08-22-2011, 17:10
I always crimp my .223 rounds using Lee Factory Crimp.

unclebob
08-22-2011, 18:18
For those of you that don't crimp, have you ever had issues with the bullet falling into the case? I loaded up 50 a while back with no crimp. I accidentally slammed the ammo box on a table and a number of them dropped down into the case... I'm sure I did something else wrong, but I'm thinking the crimp would have prevented this.

You have something very severely wrong. Either you did not size the case, wrong bullets, wrong size bullets, worn out case, sizing die not adjusted right. Just to name a few.
And no crimping the round would not have done anything. Unless you crimp in to the cannelure grove in the bullet if it has one. With the round being that lose I do not think that would have even helped.

steve4102
08-22-2011, 18:19
No crimp here. I do pay close attention to neck tension. For those you crimp do you also carefully trim all your brass. Crimping without having the same length brass will yield very inconsistent crimps.

The Sierra article was interesting that the OAL was increasing and not decreasing. Which to me is a good thing compared to the chance of the bullet being set back.

True if you are using your seating die or other taper/roll crimp die. Not the case with the Lee Factory Crimp Die, case length is not critical to consistent crimp.

StoneDog
08-22-2011, 18:39
StoneDog:

I've never had any problems. It sounds like you seriously whacked your rounds without realizing it, or you've got neck tensions issues. Out of curiosity, what was the bullet/brass combination and what kind of seating die did you use?

They were 55gr hornady FMJ's with cannelure. Brass was, I believe, Federal/Walmart bulk box (with blue primer seal) once fired by yours truly. I've not noticed this with 62gr ss109 surplus or 69 gr SMKs but then I never smacked them on a table like that. Smacking ammo on a table (in an MTM ammo case) isn't really a good practice, I get that, but the ammo should be able to handle it if loaded properly.

Before anyone jumps on me, let me re-state: Smacking ammo on a table is not a good thing and it is not a normal practice of mine... :upeyes:

JBnTX
08-22-2011, 18:49
I've chambered, extracted and re-chambered un-crimped reloads up to ten
times with no bullet movement.

This is from a magazine and manually releasing the bolt.

nc910
08-22-2011, 19:56
Man, I don't know what to tell you. Something is definitely wrong. Keep us updated, I am genuinely curious to know how that happened!

phonejack
08-26-2011, 17:17
Used to shoot high-power, been to perry,raton,wilson matches. None of the "shooters" crimp. We were after accuracy. Sorry if this offends the guys who make their ar's look like asian taxicabs

squirreld
08-26-2011, 23:15
whats the diameter of your sizing ball?

StoneDog
10-13-2011, 10:24
Sorry for the delay, I spent a few months away from the reloading bench but I'm finally getting back to it.

The ball seems to be just a hair over .22 in diameter.

I caught myself doing something this weekend that might have contributed to the original problem. The decapping pin/expander ball was seated way to far down into the sizing die and was bottoming out on the case before the die was able to size it. I'm wondering if this would leave the case mouth too wide and could be the root cause of the bullets "dropping" down into the case?

fredj338
10-13-2011, 12:04
If you want to increase the neck tension of the rifle rounds. Take about .002 off of the resizing button on the decapping rod.
Or use the Redding bushing dies.

Not even that much UB, as little as 0.005" will increase neck tension quite a bit. I have never crimped for my M1s. I am getting an AR next week, I doubt I'll crimp for that either.:dunno:
Federal/Walmart bulk box (with blue primer seal) once fired by yours truly. I've not noticed this with 62gr ss109
I submit it's the cheap Federal brass, yes it really is that bad IMO. You must have proper case neck tension. Mic your bullets, make sure they are correct, then try sizing w/o the button, see if that makes a diff. Then you'll know it's the button. You can't crimp enough to hold a bullet properly. The Federal brass is just not upto reloading @ higher pressures, even 2-3X IME.

Boxerglocker
10-13-2011, 14:49
I lightly crimp my 55 Horandy FMJBT w/c tactical rifle match loads, mainly due to variations of mixed brass. I'll submit if loading for accuracy, sorting brass, and measuring every heavy match bullet.... I probably wouldn't for accuracy reasons.

ColoCG
10-13-2011, 15:06
Sorry for the delay, I spent a few months away from the reloading bench but I'm finally getting back to it.

The ball seems to be just a hair over .22 in diameter.

I caught myself doing something this weekend that might have contributed to the original problem. The decapping pin/expander ball was seated way to far down into the sizing die and was bottoming out on the case before the die was able to size it. I'm wondering if this would leave the case mouth too wide and could be the root cause of the bullets "dropping" down into the case?


I would think that would be your main problem, cases don't work to well when they are not sized completely.
I load the same bullet you do in many different brands of brass and do not crimp and have no problem with neck tension or bullet movement in an AR.

Agent6-3/8
10-13-2011, 22:30
Not even that much UB, as little as 0.005" will increase neck tension quite a bit. I have never crimped for my M1s. I am getting an AR next week, I doubt I'll crimp for that either.:dunno:

I submit it's the cheap Federal brass, yes it really is that bad IMO. You must have proper case neck tension. Mic your bullets, make sure they are correct, then try sizing w/o the button, see if that makes a diff. Then you'll know it's the button. You can't crimp enough to hold a bullet properly. The Federal brass is just not upto reloading @ higher pressures, even 2-3X IME.

FWIW, before I got set up to load .223 I shot a lot of Federal bulk pack .223 and saved the brass. After hearing how bad they were I decided to cross section a few and compare it to some Lake City brass I have. I could find no difference in case wall or case web/head thickness. Primer pockets were crimped and required swaging.

The old stuff was certainly junk, but rumor has it the newer stuff is much better. My findings seem to support that considering all of my Federal was purchased in 2010 or 2011. Multiple loads of the same brass will tell the tale and I'll have to report back on that when the time comes. I have noticed they do tend to run short with the average around 1.742". I'm still working up loads and he hottest I've gone so far has been 24.3g 844 with a 55g Hornady FMJ. This is just plinking and range ammo I'll probably stay a little on the light side. If I really feel the need to go hot I'll break out the LC brass just for safety sake.

To answer the OP. I'm using a Lee Pacesetter die set that includes the factory crimp die. I've got it so I figure I might as well use it. ;)

StoneDog
10-14-2011, 11:43
Aren't Federal and Lake City both owned by ATK?! Not that it is relevant to this thread, of course.

Anyway, I'm going to try an expirement. I have about 100 cases that were not sized because of the improper pin setting. I have another 200 that were sized properly once I adjusted the pin.

I'm going to "load" 10 of each (minus primer and powder) and see if one set is more prone to the bullet drop. Will report back early next week.

EL_NinO619
10-14-2011, 13:43
I have had Speer rounds that do not size right. The bullet would spin in the case like cheap Remington .22. I adjusted die correctly and still would spin, sometimes the brass just sucks..

themighty9mm
10-14-2011, 15:25
Aren't Federal and Lake City both owned by ATK?! Not that it is relevant to this thread, of course.

Anyway, I'm going to try an expirement. I have about 100 cases that were not sized because of the improper pin setting. I have another 200 that were sized properly once I adjusted the pin.

I'm going to "load" 10 of each (minus primer and powder) and see if one set is more prone to the bullet drop. Will report back early next week.
Sort of. Lake city is currently operated by ATK. But lake city is government owned.

MrGlock21
10-16-2011, 23:26
Light crimp on the 223, no crimp on the 6.5 Grendel.

StoneDog
10-17-2011, 15:36
OK, I'm stumped.

I seated 10 projectiles in my properly sized brass and had no problems and I slammed the case on the table.

I seated another 10 in my poorly/unsized brass and had one drop down into the case the first time I set the case down with any authority. On the second one I noticed a second slip. On further inspection the cases seem to be deformed (expanded/blown-out) a little right at the shoulder. However, I pulled the bullet from one and properly sized it, seated a projectile again (the same one) and it would still drop down into the case. Crazy...

Anyway, apologies for hijacking this thread even if it is a bit old.

steve4102
10-20-2011, 00:19
Here is another test on the effects of crimping with the Lee Factory Crimp die vs Accuracy. Enjoy.
http://www.accuratereloading.com/crimping.html

Gunnut 45/454
10-20-2011, 09:28
I crimp everything for the AR that has a canular grove. Match bullets if I feel the bullet tension isn't enough with a slight crimp. If you chamfer your case mouth on the match bullets you dont deform the bullet when crimping! I use the LFCD.:supergrin: