To Crimp or Not to Crimp...

[Old Bob]

That is the question. 'Tis it nobler to taper crimp, roll crimp or not crimp at all. I've always crimped bullets when I reloaded for my 3 gun ammo. I put slight taper crimps on all my 5.56mm NATO & 7.62 NATO ammo. I'd run the taper die down until it contacted the bullet, then turn it down one quarter rotation & lock the die ring. I started doing that after experiencing bullet set-backs during a practice session with my 5.56 NATO AR.

Right now, none of the 6mm ARC ammo I've loaded is crimped. What I've been thinking I might do is experiment with case neck tension instead of the taper crimp. I have L.E. Wilson dies with different neck sizing bushings. What I have in the Wilson sizing die right now is the bushing suggested by Wilson which gives the Lapua brass I have a .001" smaller inside diameter than the same brass sized in the Hornady die. The AA brass I sized in the Wilson die has the same inside diameter as the AA brass sized in the Hornady die. Obviously, the Lapua brass is thicker in the neck than the AA brass. Do I change the bushing down .001" for the AA brass or put a slight taper crimp on it?

All the brass I'm using is resized 6.5 Grendel brass. The Lapua brass with their thicker necks, will it cause chambering problems? Dang! So many questions & no answers yet. I guess I'll get my answers eventually...

[Lemonaid]

If it was a choice between more neck tension or crimp, I would go with more neck tension.

[StoneHendge]

I can't comment on the main questions since I've never crimped a single round of rifle ammo and I always use an expander ball. But to check on the Lapua brass, fire the AA first, measure the expanded outside neck diameter which will be a measurement of your chamber and then compare it to the loaded Lapua.

[Old Bob]

I can't comment on the main questions since I've never crimped a single round of rifle ammo and I always use an expander ball. But to check on the Lapua brass, fire the AA first, measure the expanded outside neck diameter which will be a measurement of your chamber and then compare it to the loaded Lapua.

Good idea! Thanks!

[Phantom30]

I have crimped using Lee factory crimp dies.  I like to crimp a little because I am using powder coated bullets and the sizing is not perfect.  I have been reloading Hornady new and once fired cases.  The crimp has slightly bulged the neck behind the crimp and caused feed jams, failure for bolt to close, and failure to fire.  I have two 20" gas guns, Faxon and CMMG barrels.

[Dino11]

I have tried it both with and with out crimp,

I found that I had better accuracy with out the crimp. not by much but ever so little better. Not sure why I crimped some rounds. I never crimp bottle neck rifle rounds, and it does sometime create chambering issues. But only in one of my rifles did I have a problem, the same batch of rounds worked just fine in the others.

So it is a hit or miss type of thing, if they work fine with out then leave them alone. I you feel a little sparky then by all means give it a try, what can it hurt. It either works or it doesn't. As noted previously watch that the neck doesn't bulge below the crimp.