Crimping precision rounds?

[mzvarner]

Getting ready to start loading for a new AR 10 that I am treating as a "precision" build with the goal sub 3/4 MOA. A buddy asked if I was going to crimp in order to prevent bullet set back from recoil (we had a pistol chambered in 460 Rowland explode cause of this). I told him that my practice is to use a FL die w/ proper bushing that gives .002 neck tension. But that got me thinking if this is acceptable practice in a semi auto. I have loaded thousands of 308 and 6.5 Creedmore using this practice in bolt guns, but my AIAT is a much heavier weapon so it has very little recoil. Thoughts?

 

[918v]

You need more for a semi auto

 

[Codiekfx400]

I would agree more neck tension. Try .004 and please do not crimp the bullets.

 

[FishDr]

Increase the neck tension to be consistent. Crimping introduces a lot of variables and is more difficult to be consistent (i.e. brass thickness, trim length, etc.) For precision - consistency is everything.

 

[cornhusker86]

If you do, use a taper crimp. Make sure cases are trimmed to a UNIFORM length to avoid problems. A light crimp is sufficient. Only use bullets with a cannelure.

 

[Snuby642]

I have good results with a collet crimp, had trouble with the taper crimps and wont go back.

Imho

 

[cornhusker86]

I have good results with a collet crimp, had trouble with the taper crimps and wont go back.

Imho

The Lee collet die is a actually a really good die.