to crimp or not????

[jaykden]

i've started reloading for my imbel, just a quick question: should i crimp my bullets when i seat them or not? does it matter? i already loaded a bunch up and tried racking a round then checking the COL (2.810-just short enough to fit in the mag) , it came out the same.

[Muggzy]

The crimp does more than just put a tight hold on the bullets.

It also (as I understand it) make the pressure build-up a bit before pushing the bullet down the tube. Something like that. Suppose to be for accuracy purposes not so much for holding the bullet in place, although that is why I always put a slight crimp on them.

Sorry.. I don't have a better explanation.

Try it with and without and see if you notice a difference in the groups or if
you have any troubles with the one you do not crimp.


Some of the other guys load for Benchrest style shooting, hopefully they have a better explanation

This explains..waaayyy better than I http://www.exteriorballistics.com/re...sics/crimp.cfm

This is the results of crimped and not crimped...http://www.accuratereloading.com/crimping.html

[Nickle]

Simple rule of thumb:

If the bullet has a cannelure for crimping, crimp.

If it doesn't, don't crimp.

Like I said, simple. When I load M80 Ball, I crimp. M852 Match, I don't. Both work.

[mj2evans]

I can't help but think a crimp is another variable to effect consistency/accuracy. Yes, it helps starting pressure for difficult to ignite ball powders (H110 in a pistol as example). Yes, in a tub magazine, like 30-30, you need it. I think its a good idea for any magazine feed weapon but I think best accuracy will be without a crimp.

[Nickle]

As an ex-Bench Rest Shooter, I can assure you that if crimping the bullets improved accuracy, match bullets would have cannelures for crimping. They don't.

mj2evans is right about needing to crimp your ammo in a tube magazine. It helps in a box magazine, as well. You should also crimp revolver ammo.

[jaykden]

thanks for the info guys, i'll see what kinda groups i'm getting and also perodically overall length after the round has been chambered. the only bullets i loaded up that have the cannelure for crimping is the hronady SSTs 165grn bullets, i also loaded up hornady 165 interbond, nosler ballistic tip 165, nosler ballistic tip 150. (oh yeah, if anyone has any pet loads that shoot good out of their imbel bbls, or any FAL for that matter, i'd like to try them out in mine)

[Nickle]

42 gr of H4895 and 165/168 gr bullet. 42 gr of WC 846 works as well.

46 gr of WC 846 and 150 gr bullet, esp M80 bullets from Widener's.

I use 165 Sierra HPBT GameKings when I deer hunt with my L1A1 or M14. They feed well, and don't get dinged. They've got awesome Terminal (Wound) Ballistics. A friend shot a 565 lb moose with these in 308, out of a 788 Rem. Moose was DRT.