Home Forums Reloading Big Game Rifles Crimping?

I know there are specific caliber/gun combinations that pretty much require crimping--specifically tube fed lever actions in .30-30, ,35 rem, and .45-70 to name a few. And lets not forget the revolver rounds either.

But with magazine fed rifles....obviously there are a slew of bullets out there that do not have a crimping cannelure. In fact, from my observations, I think manufacturers are progressively getting away from the cannelure as they release new designs. But when you are seating bullets that do have a cannelure, do you crimp just for the sake of having a cannelure to crimp into? Do you believe there is some slight difference in performance as pressures may have to rise ever more slightly to "un-roll" the crimp to get the bullet moving?

Except for the rounds you note,in 50 years,I have not crimped a round whether it had a cannelure or not. Most of the bullets I have loaded that did have cannelures,the cannelures were out well past the end of case neck anyway.

I have found a slight advantage to crimping but I ONLY CRIMP WITH THE LEE FACTORY CRIMP DIE. In 3 separate tests crimping with the LFCD has increased velocity by an AVERAGE of 10 fps and decreased group size an AVERAGE of 1/8" (some more than others)



The LFCD does not need to crimp into a cannelure and it is easy to use to set a light, medium or heavy crimp as you want. They are cheap and fool proof.

Is it necessary? No. Will it always improve accuracy? No. Does it help sometimes in some rifles? Yes. Does it ever have an ill effect? Not IME.

There is also a certain peace of mind with not having to worry about the bullet moving either in the mag from recoil, compressed powder pushing it out or mishandling.

sometimes its interesting what little things can change or improve accuracy as I read a very interesting article about the 22 hornet here a few years back and these guys got similar results by switching to small pistol primers the groups would sinch right up and with small rifle primrs the groups would open up considerably,very interesting information and thanks for that tidbit...............

Very interesting, woods. Thanks.

I have found the same thing that woods said to be true. And sometimes I just crimp slightly to remove the proud square edge of the case mouth as it can affected reliability slightly in some situations.

My results exactly. I've had Lee factory crimp dies for all my rifles now. jorge

I posted a question about this quite a long time ago and didn't really get an exact answer.

It is Lee's contension that crimping serves the same function as seating a bullet "on the lands," in that the resistance forces a more uniform pressure curve.

It would make more sense to me to compare it to dies like the Redding type s neck sizer which allows the loader to manipulate neck tension, but even so, it makes sense to me.

If you're looking to seat bullets X-thousandths away from the lands in any given rifle the Lee Crimp is the only choice, since in all liklihood you won't be crimping in the groove.

I don't crimp all of my ammo, but I do experiement with it when developing a load. It is one factor amongst many that can add some consistency and accuracy to your loads.

I have heard of the Lee Factory Crimp Die before, and hearing you guys speak of it has got my interest peaked. Would I be correct in assuming that this die only crimps the case neck and serves no function at all in seating the bullet to a specific depth?

You would be correct in assuming that War Eagle.

War Eagle,

Not only that, but unlike the conventional "roll crimp" that comes in RCBS seater dies, this one utilizes a collet. You don't run the risk of deforming the case if you get "to into" the crimp.

As a matter of fact, Lee claims you can even crimp bullets that lack a canelure. I haven't ever tried that though.