To crimp or not to crimp

[lrgrendel]

Shooting 6.5 Grendel AR just recently purchased. Had it out twice only. Shooting less than 1 MOA at 100 and 200 yds. So far with virgin Lapua brass. Am single loading as I am not crimping and am concerned. Have only reloaded with the virgin brass as of now.

Will only be shooting on a bipod from a bench or prone.

Only have a Forster Benchrest full length resizing die and a Forster ultra micrometer seating die.
What about increasing the neck tension instead of crimping?

I know this has been discussed before but I can not find it.

An explanation would be a great help.
I guess there can be some safety concerns.

Thanks

 

[SnkBit]

Don't crimp. If you're concerned about bullet movement put a few in the mag, shoot a couple rounds and measure the rounds that remain in the mag. I would be very surprised if you ever see any movement.

 

[ksthomas]

lrgrendel,

Neck tension alone. As SnkBit said, there's no reason to crimp if you've got adequate neck tension, and it adds yet another unwanted variable into the equation.

 

[garandman]

I've heard it said "Crimp a semi rifle. Don't crimp a bolt gun."

Crimping likely produces an impression (however small) on the bullet jacket. Which if you could get it EXACTLY the same every single time MIGHT not matter.

I used to crimp everything, and had sub MoA accuracy. Now I don't, and have about the same accuracy, maybe a little better. My crimps were SUPER light. Basically I used the crimp die to improve neck tension.

As above, neck tension should be enuf for a bolt gun.

 

[gvanhyning]

I had a 6.5 Grendel auto-loader I reloaded for and never crimped.

 

[Drifter™]

I don't crimp because neck tension is insufficient, but I often try it to see how accuracy is affected. Sometimes it helps, while other times it doesn't.

I use a Lee FCD in a Lee hand press and take it along to the range. This allows me to easily try a load both ways. I use a very light crimp.

Here are before-and-after crimp pics with the exact same load using new brass in a 6.5 Grendel.

No crimp (3 shots):



With crimp (5 shots):

 

[ksthomas]

lrgrendel,

I answered your email, but it got kicked back as "undeliverable" when I sent it. Might go through later, or you can PM me here. Thanks.

 

[lrgrendel]

Thanks for the replys guys.
Not sure why your email did not go through Kevin

 

[ksthomas]

See if it might come through yet, and if not, a PM will do. Not a problem!

Headed to a match this weekend and leaving out tomorrow. Don't know if I'll get any time on the 'puter, but I'll try. Catch you then.