Will case crimping improve accuracy or change point of impact?
I started crimping the cases of my 375 H&H magnum loads last week. The rounds are more accurate and the point of impact has shifted. Has anyone else had this happen? I had to shorten the AOL of the rounds to crimp them and I was wondering if it was the longer distance to the lands that has affected the accuracy and the point of impact rather than the crimping?
Thanks.
12 July 2002, 09:27
<J Snyman>The golden rule when reloading is to never change more than one thing at a time as you won't know what caused the difference.
You will now have to go back to where you started, and do it over again.
On your rifle/load combination seating depth and crimping may/may not influence accuracy.
Johan
12 July 2002, 02:01
<eldeguello>I do not believe crimping rifle ammo is better. I don't acccept the claim that crimping improves accuracy, particularly if crimping changes the bullet in any way! But, a heavy crimp is absolutely essential in some kinds of pistol ammo if one is to get complele burning of powders like H110 and WW 296!
12 July 2002, 03:12
BIG SAMRon L,
We got LEE Factory Crimp dies for our big bore rifles. I didn't see much, but there was a little difference in P.O.I.. The biggest difference that I have seen was I had to back down my powder charge in to keep the same velocity.
(ie.) 104.5gr H4831SC down to 102.5gr. in my .416 Rigby. The .375 only needed a 1gr. reduction.
The accuracy has remained the same.
The price of this special die is approx. $25.00 and they will make you one if it's not listed in their catalog.
All the best,
SAM
13 July 2002, 00:17
<stans>I can say from my experience with pistol cartridges that crimping does help, at least with pistol rounds. I recently conducted and informal test using 3.6gr W-231, 148gr LDEWC, WSP primer in 357 Magnum cases. I loaded some with no crimp, some with just a hint of a crimp, some with a moderate crimp and some with a heavy crimp. I found those with a moderate crimp were more uniform in velocity and were just a little more accurate.
13 July 2002, 16:05
Ray, AlaskaSaeed has some information about crimping, right here at this site. Scroll down to the bottom of this page to "accuratereloading.com," and look for FAQ's.