Home Forums Reloading Big Game Rifles To crimp or not to crimp, that is the question

Do you crimp your reloads? Is there any reason to do it or not do it? I am loading for my 308 and have been but not real sure why it is needed. Does it make a difference in accuracy, or brass longevity?

Thanks,

Only for lever actions, 375's & 458's.

MM

I crimp for most everything that doesn't headspace on the case mouth.

there you have it..

Swampy is a Contra-indicator...therefore...don't crimp!

Many moons ago I discovered improved accuracy using a Lee Factory Crimp die. I've just kinda kept the habit since. I reload mainly for hunting so ensuring the bullet doesn't move is more important to me. If I was into competition bench then I suppose I would fiddle around with no-crimp and miniscule adjustments from the lands. Meh.

Ammo for the lever actions with a tube magazine and in handguns, the 38 Spl and 44 Mag get crimped. Nothing else.

Dale

Ditto on the lever actions and handguns. Also large volume cases with slow powders sometimes benefit, IME.

Factory ammo is crimped. There's a reason for that.

I only crimp for heavy recoiling doubles and bolt action rifles, and a slight taper for all semi-autos, and a medium roll crimp for revolvers and levers

Gunner

edit: still can't spel.

I usually don't crimp for TWO (2) reasons...

1) It isn't necessary in most cases since the sides of the cartridge neck are tight against the waist of the bullet and normally hold the bullet solidly in place. The possible exception to this rule would be when straight-walled cases are used to hold short, fat bullets in cartridges yielding heavy recoil such as in .44 magnum and other heavy recoiling rounds using straight-walled cartridge cases and short, fat bullets.

2) Crimping tends to raise the chamber pressure somewhat because the bullet resists moving due to the crimp holding the bullet in place in the cartridge case.

Over the 50 years of reloading I've done, these are the reasons I've read about and learned when reloading bottle-neck vs. straight walled cases.


Strength & Honor...

Ron T.

OK, what's the reason?

It lets pressure build before the bullet starts to move. This results in a more consistent burn. IMO it helps accuracy.

No crimp for centerfire ammo. I spend quite a bit of time keeping the brass straight, why would I elect to bend the mouth?
Factory ammo is crimped to accommodate a large variety of actions and knuckheads.

I used to have a Sako AIII in .30-06, nice shooter, standard load was 168 TSX's over IMR4350.. Back up load was 165 AB's over the same charge. Same primer, case, yadda yadda..

For chits and giggles, I tried out the Lee crimp on them, and it shrunk the TSX's up by half, and didn't do chit to the AB's.

Take it for what it's worth.

Swamp, the factory also chooses the powder charge, seating depth. Also chooses the trigger pull weight, lack of bedding, etc. Should we accept all those since the factory does that? I think not. We load our own and tinker with our equipment to get better results. I crimp all my pistol loads very few rifle loads and only after testing for accuracy/reliability. Doing something because the factory does shows a lack of understanding of the loading process. You should just shoot factory ammo since that is what they do.Rick.

sorry ricsmith, i just hit reply but it is not to you but to swampman500!



WTF cartridge HS on the case mouth? shoulder or belt yes and even belted cases i would HS on the shoulder.

WOW! shame on you! do you crimp bullets that dont have a canneleur? (spelling)

Crimp nothing that don't need to have it like tube feed lever actions!
NO WAY will it help your accuracy!

I dont even crimp 44mag or 357. maybe 500S$W if you think your bullets will come loose under recoil? but i doubt it?

Many pistol cartridges and some rifle cartridges headspace on the case mouth. Yes, I lightly crimp on bullets that don't have a cannelure. If you don't crimp .357 & .44 Magnum your bullets will lock up your revolver as they move forward under recoil. It helps accuracy. Slow burning powders like 296 and 110 in the .44 and .357 can lodge a bullet in the barrel without a crimp.

you meant to say rim? the back of the case,for 357 and 44M.



BADLY deforming the bullet!



you must have your taper die set too deep then.

in order to get an even crimp, you would have to trim your cases after every fireing then. so what trimmer do you use?

Very few, if any, 45ACP,9mm, 10mm bullets have cannelures on them unless they are cast. I don't know of any std die set for these rounds that does not have a taper crimp.

I crimp for revolvers and semi-auto pistols.
I also crimp for Tube Fed Lever guns, rifle and pistol cartridges.

I haven't crimped a cartridge for a bolt action rifle in 20+ years.