CRIMP OR NOT TO CRIMP

[spudgun]

Been reading some stuff on my 224 Valk.

One read was on crimping the bullets to increase accuracy.

Seems that this person says that a crimp on the bullet will increase the accuracy due to the bullet leaving the neck of the brass evenly as opposed to a non crimped bullet.

Not worried about the bullet changing position in the chamber due to recoil.

Any opinions??

 

[SRM]

AR-15, crimp
Bolt gun, no crimp
Really don’t want the bullet moving around once the sweet spot has been found.
Depends on the bullet also.

 

[SSL]

My theory (right or wrong) has always been that I don't want my bullets altered in anyway, even faint scratches, by crimp pressure. Maybe I'm just being paranoid. Also, when crimping, trimming must be kept constant so that each crimp is applied as close to the same as possible from round to round. Adds another variable to an already long list.

Just in my own experience, years ago I tried some .223 loads, identical in every other way, both crimped and uncrimped. The uncrimped group considerably better than the crimped. Granted, far too small of a test to be truly determinative, but enough for me to not experiment further.

Yes, in lever actions that are tube fed or any straight-wall handgun cartridge I always crimp. This is done both to keep the bullets in place under recoil or feeding and to assist certain of the slower (such as 2400) handgun powders to burn better.

 

[Bill K]

Been reading some stuff on my 224 Valk.

One read was on crimping the bullets to increase accuracy.

Seems that this person says that a crimp on the bullet will increase the accuracy due to the bullet leaving the neck of the brass evenly as opposed to a non crimped bullet.

Not worried about the bullet changing position in the chamber due to recoil.

Any opinions??

The only way you will know what works best in YOUR rifle is test. What works in one persons, may not be what your rifle likes. I do crimp my AR loads, but in bolt rifle, in 224 Valkyrie, I don't.

 

[GAnderson]

Instead of crimping, go with a tighter neck tension. Not had a problem in AR's doing this.

Gene

 

[garandman]

Crimping introduces another variable. Variables are usually bad news.

My take on it is don't crimp unless you absolutely have to.

See disclaimer (below)

I got a 224 Valkyrie bolt gun coming to me from Southern precision rifles. So I will test out my theory there

 

[searcher]

I shoot .223, 6.5 Grendel, .20 Practical and .22 Nosler in A/R's and don't crimp any of them with the exception of ammo I run through a Dillon machine for shooting steel and larger critters like coyotes on up. While some obtain better results from crimping - I think it is usually a situation where their particular load liked the crimp better for reasons that do not necessarily make crimping the best overall accuracy choice. There are many mechanical disadvantages of crimping, though the main culprit is getting uniformity in tension (assuming you didn't tweak the bullet). Factory brass (even the best) is not uniform in the neck thickness. If you were capable of setting your die to gingerly provide just enough neck crimp to hold the bullet firmly, yet not deform the bullet, you achieve an ideal crimp. The problem is when you crimp that neck that is .002" thicker than the "ideal" setting as aforementioned. Now you have a possible slightly deformed bullet AND a crimp that will release differently. And a thinner neck will create yet different level of tension. And just try setting your crimper to achieve that perfect crimp. #@*5#! While one will encounter different neck tensions even with turned necks and no crimping - the affected differences in release will be far less than if crimped - whether the necks are turned or not. The U.S. Military has long recognized that non-crimped ammo outperformed crimped in testing and some other countries make their ammo with a sealant designed to eliminate the need for crimping. An example of that is with WOLF GOLD ammo for those who have dissected a round. In my own experience - I never obtained fantastic accuracy crimping, though good accuracy for other than precision target shooting can be had. That is when I break out the trusty Dillon machine and put away the hand dies.