Crimping for AR15?

[1jonathan1994]

Is crimping required for AR15? I was just blissfully setting .002" neck tension.
Would it be different requirements for 77smk seated below the shoulder vs barely seated 55gr?

 

[RTH1800]

Depends.

If you are getting consistent velocities over large round counts in varying conditions it’s doubtful. That being said I use a RCBS taper crimp die on mine.

Some time ago I was speaking with Alan Brown from Crane and he suggested I try it for more consistent velocity and reliability. It worked and I continue to utilize it on all my 5.56 ammo.

YMMV.

 

[1jonathan1994]

Someone suggested the bullets could move when the bolt slams shut.
That's detrimental to accuracy at the least and dangerous at worst.

 

[smoothy8500]

.002" neck tension without crimp is fine.

 

[RTH1800]

Someone suggested the bullets could move when the bolt slams shut.
That's detrimental to accuracy at the least and dangerous at worst.

This will show up on chronograph.

 

[Mr Tibbs]

PutTing a lite crimp on your hand loads Just enough to prevent bullet set back while the round is hitting the feed ramp on it’s way into the chamber . The only rounds that don't need a crimp applied are those being fired in a single shot / open breech rifle/pistol IE T/C’s. There is no feed ramp !

 

[rweaver00geo]

Have you slammed it home a few times and remeasured it with a caliper to see if its moved. I would avoid crimping match bullets and even some thin skinned varmint bullets if possible. I did some crimp tests with some bulk 55 grain soft points and it did improve the ES/SD numbers however my group opened up a bit...go figure

 

[MTRecon]

Depends on the bullet and load...

Never had any problems with no cannelure match bullets...for bullets with cannelure I test with different crimp levels and sometimes get better consistency with a crimp...

 

[Jumper]

If the bullet has a cannelure I'll usually seat to it and crimp it. My SDs are usually single digits if I sort cases by headstamp.