To crimp or not to crimp?

micksis86 · January 20, 2011, 02:06 AM

I've just started reloading for my 338 Win mag and it's the largest cartridge i've loaded for the previous largest being my 308 or 270 winchester.

The bullets I have which are hornady 250gr interlocks have a cannelure on them but i'm wondering wether to crimp them or not.

I'm using a ruger M77.

HiBC · January 20, 2011, 02:19 AM

I am not going to say you should crimp.I have not crimped rifle loads yet.
I did just buy a Lee collet type factory crimp die for about $13.
I am going to see what a light crimp does for accuracy in a .223.
For $13,I can find out.

micksis86 · January 20, 2011, 02:42 AM

I'm going to load some round up and fire them to get used to the rifle and recoil etc as i haven't fired it yet and think it'd be unwise to fire a 338 Win mag for the first time during load development.

So i'll probably use uncrimped rounds then and see what happens with them in the mag. See if any setback occurs.

PawPaw · January 20, 2011, 06:46 AM

With the .338 Win Mag, I'd be concerned about setback and a crimp in the cannelure is good insurance about that.

However, it might not be a problem, but you won't know until you do the range time. I believe what I'd do is put one uncrimped round deep in the magazine and not shoot it during the course of the range session. Let the round stay in the magazine and load over the top of it. Let that round absorb all the recoil of that range session, then measure it. If's it's shorter, then you have setback problems. It it's not, then you don't.

sourdough44 · January 20, 2011, 06:49 AM

If the bullet is held firmly by the neck I wouldn't see any reason for dedicated crimp. Some brass/bullet/neck combinations can potentially leave the bullet to loose,usually not though.

PIGMAN · January 20, 2011, 06:56 AM

I crimp ammo used in my semi auto rifles only. I have found that various seating depths for my different rifles of the same caliber does make a difference in accuracy so crimping to the cannilure from my experience would sacrifice accuracy

January 20, 2011, 02:06 AM	#1
micksis86 Senior Member Join Date: June 16, 2009 Posts: 420	To crimp or not to crimp? I've just started reloading for my 338 Win mag and it's the largest cartridge i've loaded for the previous largest being my 308 or 270 winchester. The bullets I have which are hornady 250gr interlocks have a cannelure on them but i'm wondering wether to crimp them or not. I'm using a ruger M77. __________________ Never argue with morons, they will lower you down to their level and beat you with experience.

January 20, 2011, 02:42 AM	#3
micksis86 Senior Member Join Date: June 16, 2009 Posts: 420	I'm going to load some round up and fire them to get used to the rifle and recoil etc as i haven't fired it yet and think it'd be unwise to fire a 338 Win mag for the first time during load development. So i'll probably use uncrimped rounds then and see what happens with them in the mag. See if any setback occurs. __________________ Never argue with morons, they will lower you down to their level and beat you with experience.

January 20, 2011, 06:46 AM	#4
PawPaw Senior Member Join Date: December 24, 2010 Location: Central Louisiana Posts: 3,137	With the .338 Win Mag, I'd be concerned about setback and a crimp in the cannelure is good insurance about that. However, it might not be a problem, but you won't know until you do the range time. I believe what I'd do is put one uncrimped round deep in the magazine and not shoot it during the course of the range session. Let the round stay in the magazine and load over the top of it. Let that round absorb all the recoil of that range session, then measure it. If's it's shorter, then you have setback problems. It it's not, then you don't. __________________ Dennis Dezendorf http://pawpawshouse.blogspot.com

January 20, 2011, 02:19 AM	#2
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,283	I am not going to say you should crimp.I have not crimped rifle loads yet. I did just buy a Lee collet type factory crimp die for about $13. I am going to see what a light crimp does for accuracy in a .223. For $13,I can find out.

January 20, 2011, 06:49 AM	#5
sourdough44 Senior Member Join Date: October 17, 2007 Location: WI Posts: 621	If the bullet is held firmly by the neck I wouldn't see any reason for dedicated crimp. Some brass/bullet/neck combinations can potentially leave the bullet to loose,usually not though.

January 20, 2011, 06:56 AM	#6
PIGMAN Senior Member Join Date: January 7, 2011 Location: ARIZONA Posts: 175	I crimp ammo used in my semi auto rifles only. I have found that various seating depths for my different rifles of the same caliber does make a difference in accuracy so crimping to the cannilure from my experience would sacrifice accuracy