AR reloading...no crimp?

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WhiteShark

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Hello all,
I'm new here, and new to reloading so advice would be most appreciated. I recently started reloading for my A.R. 15 and after some research, and some suggestions people are saying do not crimp for best accuracy but rely on the proper neck tension contacting the bullet. High power and competition shooters seem to loath crimping even for AR's.

Anyways what is the best method and die set up to get proper neck tension to reliably with-stand a magazine fed A.R. action? Also looking for the best neck concentricity. Expander vs bushing? Or both?
 
Welcome to the forum...

I have crimped rifle ammo and shot it without a crimp. I could find no difference since I probably don't own rifles which are good enough to see a difference. Is it necessary, no. Should you? Do both and see which is better for you and your rifles...
 
I don't crimp mine. Even it it has a cannelure.

I resize with a RCBS X Die.

Haven't had any problems out of ARs or a Ranch Rifle.

I did order and receive a Lee Crimp Die. I crimped a few but haven't shot them yet.

Good Luck
 
Most manuals will say to crimp ammo for semi auto rifles.
It's up to you. There are many who do not.
 
Welcome Shark.
I'll try to give a quick answer to your question about how to set up dies for optimal neck tension. The answer is that you can't control neck tension with standard sizing dies without modifying the dies. The internal dimensions of the sizing die body is going to size the neck down just so much. No change in the setup is going to change that internal dimension of the die.
Then, the expander ball is going to increase the inside dimension to the size that the manufacturer deemed correct. You also can't control that in setup, but you could alter the expander ball by changing it out to a smaller one or stoning a little off the outside dimension of the ball (I've never had to do either).
Here is an example of what sizing does to the neck. I just picked a once fired case out of a box and sized it. It's a once fired Lake City 556 fired in a military weapon of some sort.
The outside measurement on the neck before sizing was .257"
I sized it in a Forster 223 full length die with the expander ball/stem taken out and got an outside neck measurement of .240"
Then, I sized it again with the expander ball/stem installed and got .245".
The inside dimension would depend on the thickness of the brass, but gives good neck tension in all of the brass I have encountered.
I've loaded 223 since the early 80s with several die sets and they all gave adequate neck tension for ARs without modifying the expander ball and without crimping.
Some folks like to crimp and get good results also.
 
I don't crimp.

I use a standard RCBS FL 2-die set. Neck tension is outstanding. I can't budge the bullet in a "press test." Just follow the directions that come with the dies. It's that simple.
 
Thank you for all the replies! I'm going to try seating bullets without a crimp and then do a press test to see what happens. My expander ball measures .222, so that'll leave me with .002 neck tension.
 
The only way to know for sure is to load a large enough test batch both ways and shoot them to see. If you do not want to length size them every time get the Lee Factory Crimp die. As long as they are not over SAAMI max the die will crimp them all equally. I own one. I tested my ammo in several rifles trying both crimped and uncrimped. MY uncrimped were more accurate and also saved a step when reloading. Many others have better luck crimping theirs. Let us know your verdict after testing a bunch.:)
 
My name is Chuck and I do not crimp for ARs, M1s or M1As

Besides, I shoot very few bullets with a cannelure so crimping is not particularly easy.

Many folks find crimping improves accuracy, many do not. So, as FROGO207 said, you need to determine what works best in your rifle.
 
Hi! My name is not Ron.
And I go both ways, sometimes.

But when I do?

I don't crimp .223.

I do crimp for lever-actions and revolvers though.

rc
 
I don't crimp jacketed .223. I also load mine too long to reach the cannelure, anyway.

I crimp cast .223. The blunt nose of these bullets takes a beating when they chamber. Without a crimp they would jam and setback all the way flush with the case mouth.

If you're worried, chamber the same round a few times and measure the before and after.
 
Another heads up, is pay close attention while you are withdrawing the expander ball, after sizing. I have thrown out more 223 cases for loose necks than any other caliber, personally.

If you don't feel the expander ball drag thru the neck with at least a little bit of resistance, toss the case (or set it aside for annealing, if you do this). This is easier and way more accurate than bench-testing all of your loaded rounds, and you won't need to pull down any loaded rounds for bad neck tension after-the-fact. Unless you run into an undersized bullet, anyhow.

Now, if your sizing die is really tight in the neck, you will practically never run across bad neck tension and you will have nothing to worry about; you will probably have a bigger incidence of cracked, crooked, and stretched necks and shoulders, though. You can get a good estimate as to where your die stands by how hard it is to pull the expander ball through. I have some rifle dies where the expander barely touches, and others where pulling the expander out is like giving birth. If you have an issues, be sure to measure your expander ball. It should be just about .222".
 
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You don't even need to measure.

Draw a black line around the bullet at the case neck with a fine-line Sharpie.

If the line has gone into hiding the next time you look, you have set-back!

rc
 
Gloob, what would make the case not contact the expander very much? Is that when the brass is nearing it's end of life cycle? Does annealing help this?

Rcmodel, very nice method with the black sharpie tip!
 
If your sizing die is loose enough in the neck, some brands of brass just won't even work with your dies. The brass can be so thin in some brands that the sizing die can't make the interior diameter small enough to hold neck tension.

The other thing is the more times you fire and size a case, the neck work hardens. This makes it less malleable and makes it act more like a spring. If it was just barely sizing tight enough to begin with, it will start to loosen over time. This is because the brass is opening up to the chamber dimension when fired, then contracting back a little more than before, because it's work hardened. But conversely, when you size the case, the neck is squeezed down to the size of the die... but it opens back up a little more after it pops out of the die. Hence, the sized neck gets bigger and bigger over time. Eventually big enough that the expander ball doesn't even drag on the case.

The easiest and most foolproof way to detect this is to feel as you pull the expander ball through the neck.

Now that said, if your dies are on the tight end of the spectrum, you may never experience this phenomenon. But I bet you will have a bit of extra work pulling your expander ball thru the necks.
 
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no crimp

The fellows and gals shooting High Power Service rifle matches - the last stage of which is at 600 yards....use bullets that have no cannellure and are not crimped.
Same for the 300 yard rapid fire stages.
Pete

PS _ having not met every HP shooter, maybe there is someone who crimps those bullets....I haven't met him or her yet.
Pete
 
No crimpy here. Anytime I can cut out a step, Im all in. (and my name is not Ron)
 
rcmodel said:
Hi! My name is not Ron.
And I go both ways, sometimes.

But when I do?

I don't crimp .223.

I do crimp for lever-actions and revolvers though.

rc
Click to expand...
Rc,
I wouldn't have thought that-

You know somebody had to point out that play on words..
 
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