To crimp AR ammo

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dan158

New member
I read some from search and was curious about crimp and non crimp for the AR.
If the bullets are crimped would the bullet when it first breaks free from the case lodge a bit deeper in the lands before it takes off out of the barrel compared to just say a pop and stops not as deep in the lands as non crimped?

Also from being crimped in an AR would it help keep the bullet seated at the same OAL better when being slammed forward and stopping than a non crimped bullet might move a bit out of the case changing where it might be from the lands when fired?

As my first question, could this be why the 204 likes a jump? It gets better seated in the lands than if was closer.


Thanks all. Dan
 
Originally Posted By: dan158
Also from being crimped in an AR would it help keep the bullet seated at the same OAL better when being slammed forward and stopping than a non crimped bullet might move a bit out of the case changing where it might be from the lands when fired?



Thanks all. Dan


This is my concern. I don't crimp anything I reload but for this reason I may start to crimp my AR rounds. I have done more range shooting than hunting so I haven't had a reason to worry. But I feel that this reason may be a valid reason to start crimping for any semi auto. Rifle or handgun.
 
I'm another who has never crimped and my ARs get bounced all over the place.
No matter how you do it there wont be any difference into the lands as that's all on your COL, not how its crimped or not.
 
It sure does take a lot of pounding with a bullet puller to unseat a bullet...not that I have a lot of experience pulling bullets...
 
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Has anyone checked a round before and after being slammed forward in an AR and what was the results?
Has anyone done an accuracy test between crimped and non crimped in an AR?
Thanks all. Dan
 
Originally Posted By: Hookedhttp://leeprecision.com/reloading-dies/rifle-dies/factory-crimp-die/

http://www.hornady.com/ballistics-resource/internal


I think for the cost of the Lee crimp die, it is worth a try; YRMV

This is what I thought also before reading the link. Thanks Hooked.
The below actually makes sense to me.

Tests demonstrate that even bullets with no cannelure will shoot more accurately if crimped in place with the Lee Factory Crimp Die. A firm crimp improves accuracy because pressure must build to a higher level before the bullet begins to move. This higher start pressure insures a more uniform pressure curve and less velocity variation. Even powder selection is less critical. Until now, handloaders seated the bullet to touch the rifling to achieve similar results. This is not always possible nor desirable.
 
Well Dan, take it for what it`s worth; an advertisement...

This subject on bullet crimp comes frequently, and has about as many who swear by it as those who despise it.

For the price of the Lee die, it is worth trying IMO.
IME, I have had very good results using the crimp, and no (or perhaps, less) worries of the bullet moving in the case.
 
sometimes when the hunting is not so good, a round will be chambered and extracted many times before it is used. it will get a little scratched up but i have never had a bullet move.
i crimp with heavy revolver loads, and lever actions loads. but even on a heavy recoiling rifle like a 338 win mag, i do not crimp and have never had an issue.
 
^^^ This except for the fact that I have had a bullet pushed back some into the case when the top round in a hunting mag is loaded and extracted multiple times. Maybe it is a brass, sizer die, mag, feeding, ramp issue or a combination but I like to crimp my AR rounds a bit.
 
I actually tested crimped vs uncrimped 64 grain winchester bullets,,,, I wasnt real scientific,,, cause my rifle didn't like em much either way....but the spread was larger on the crimped ones...about 25 rounds each fired,,, now they are all SHTF ammo.





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No crimp here either. It's plenty accurate and have measured rounds after a couple of times being chambered and no change. I did spend about 5 minutes trying to pull a bullet so I foresee no issues in my brass
 
No crimp here.

I take a few random rounds from the batch and stand them one at a time on my bathroom scales, then use a small piece of wood to push straight down on the bullet. If it doesn't move with 50 lbs. of pressure, then I don't worry about it.

 
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