Home Forums Hunting & Shooting AR and Tactical Rifles Crimp or not?

Crimp with the Lee crimp die...

A 16" AR carbine can be a lot more accurate than you might think. Obviously it depends a lot on the barrel and ammo, but below 1/2 moa is a reasonable expectation with the right load. At that level, crimping may or may not affect accuracy, you'll have to try it, although it's telling that most precision shooters do not crimp.

As to whether you need it or not - it's belt and suspenders, up to you to make that call. Neck tension alone should be plenty to resist bullet setback, and always has been for me, but if you've got something not right in the load process, like an expander ball that's too large, crimping might save you. Personally I don't bother, other than to just remove the flare when loading cast bullets.

Yes, crimp with the Lee Factory Crimp die.

I know when I tried to load the Winchester 64 PP and saw how easily they were moving I adjusted the Lee FCD to a pretty darn heavy squeeze and got them to hold. I was still scared of pushing a bullet in and creating a big pressure spike cause I always seat a mag and release the bolt to load. I checked the first 2 rounds I put into battery and found they were pushed back.

I'm not saying that happens to properly sized bullets that are being held by properly sized case necks, I can't, but I do think there are forces that could affect seating depth when the bolt moves forward into battery. Like MM said , you would have to eject and caliper a bunch of them to find out.

I think I could do that with ammo made up with no primer or powder. Without the minuscule chance of a slam fire I could test this at home. That would tell me about my sizing mandrel.. and the bullets I use.. in that one gun..you'all are on your own.

You can also measure the ID of the case necks & the OD of the bullets being used to see how much interference fit you are getting.................nominally, .002-.003" is typical & works fine, depending of course, on the hardness of the particular brass.

MM

There ya go... we loaded up to 20K a year for Carolyn and I and a couple of juniors here and there... from about 89 till 2004.... thats a few rounds.

I don't even know if I have a crimp die for a 223.... full case of powder, control neck tension with a collet the right size.

The only case that I ever needed to crimp was lead bullets in my .454 Casull. Walking bullets will lock up a cylinder in a hurry. There was a newspaper guy here who had that happened when he was trying to fire the second shot at the bear.

Jeff, It's Whiskey Tango Foxtrot, over..

edit on the way. LOL

They get pissed around here on the fire radio if you talk about over or roger... or God forbid Niner....

I use a Lee FC die.

What the foxtrot? I learned all my radio protocol in the Artillery, over.

You might know what "Fire for effect" means, then. (grin)

This ^^
If I buy ammo that is not crimped and it's destined for a semi auto, I crimp it.

kwg

yep, sure thats why all the winning AR shooters in highpower/service rifle crimp all their ammo all the time, it helps groups and reliability.... LOL Then again the way most shoot an AR it sure won't hurt the accuracy....

Never mind the fact that I know more than a few with at least half a million uncrimped rounds in the AR with never a crimp related issue... but then we do tend to use 100 percent fill and control neck tension the better way, via bushing rather than crimp.

I don't trim AR brass so this method won't do me much good