Fellas, can someone please explain to me what the difference would be in accuracy if any, in a heavy crimp compared to a light crimp?? I am mainly refering to my .38-55 lever action as i am still trying to dial it in.

Mark I have not done a lot of reloading for lever rifles, but have loaded for a 44Mag a 30-30 and a couple of 45/70's. I always used a pretty good crimp to eliminate any problems with the recoil/magazine spring pushing the bullet back into the case. If you can find an accurate load where the powder is barely compressed it will help stop this problem. If you have problems with the cases "buckling" as you are seating and crimping you can try seating and crimping in two seperate steps, which is how I usually do my rifle loads.
As far as accuracy goes only, by trying different crimp amounts in your rifle can you tell. In a lever I worry more about reliability than any slight difference in accuracy.

[ 05-26-2003, 09:22: Message edited by: N E 450 No2 ]

Mark
What I've done with my 45 Colts, 44 Special, 357, 45 acp and more to the point 45-70 and 375 Whelen, is to polish the neck expander down a bit. For the rifle cartridges that is the Lyman 'M' die. For the pistol cart. it's the powder thru expander on the Dillon presses.
I polished the Lyman 'M' die expander with fine emory cloth then crocus cloth until the expander was like a mirror. This gives a very tight grip on the bullet while still allowing the mouth to be flared for easy bullet starting. The flaring is important since all of the above cart. are shot with cast bullets exclusively.
I use a substanial crimp on all of the straight sided cases and no crimp at all on the 375 Whelen.
Don't need to with the tight case neck.
Jim

Mark
I'm sorry I was so ready to evangelize about tight case necks I didn't answer your question.
As I understand it the crimp is used foe two reasons.
One keep the bullet in place on the loaded cart during handling.
Two hold the bullet in place for a nano second longer, provided resistance to the burning, expanding powder gases for a more complete burn. The resistance provides a more uniform pressure curve.
Jim

You need both tight grip by the neck and crimp.This to prevent set back and provide proper burning. Excessive grip may cause problems due to distorting the bullet.

NO difference in a light or heavy crimp, if all are the same. Trim all brass to exactly the same lenght before crimping. I have notice lower velocity in some ammo (45acp) when heavy crimping was used. If at all possible do not crimp at all, only crimp if the bullet is moving or being pushed into the case.