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Using a 308 Win Crimp die on 30-06

Posted: Fri Jul 06, 2018 5:48 pm
by Inarus
Good afternoon guys and girls.

I was running some 30-06 on my XL650 and a thought occurred to me. I am making 30-06 ammo for my M1 Garand but am currently not using a crimp after seating my bullet.

I am using mil-surp 30-06 brass, Hornady 150g FMJ-BT with cannelure, and seating with an RCBS seating die. All brass has been full-length sized, trimmed to 2.48, chamfured, deburred, and reamed using my Frankford Arsenal case prep center.

I have always crimped my ammo when loading for semi-auto rounds but I have never crimped my 30-06 for my Garand. I've loaded and shot approximately 300 rounds using this brass and bullet behind 45.5g of IMR 4895 over CCI 34 primers.

What I am wanting to know is could I use my 308 crimp die to put a slight crimp on the ammo? Just unscrew it far enough to where it only just crimps the bullet to prevent setback due to the semi-auto action.

Given the diameter of the bullet is the same and the diameter of the case is the same I don't see why you couldn't, if you just backed the die out far enough to only come in contact with the neck.

I know the neck of the 30-06 is longer, the shoulder is more shallow at 17 degrees, and is also a little longer than the 308.

So, could it be done?

Re: Using a 308 Win Crimp die on 30-06

Posted: Fri Jul 06, 2018 5:55 pm
by DaleH
Sure, or add washer that slips over the case when it is in the shellholder, thickness same as difference in case lengths between the 2. Or washer under the die if you screw the die in/out for caliber changes.

Re: Using a 308 Win Crimp die on 30-06

Posted: Sat Jul 07, 2018 11:10 am
by Inarus
So I tried it today both on my Lee turret and my Dillon XL650.

I'm going to guess that the crimp activates when the bottom of the die touches the shell plate, pushing the internals up and closing on the crimp. Because the die did not work at all. The entire neck of the 30-06 round came through the hole in the middle of the crimp die. It only stopped when the shoulder stopped the forward motion of the round.

So for anyone in the future who asks, no. A 308 crimp die cannot be used for a 30-06 crimp.

Re: Using a 308 Win Crimp die on 30-06

Posted: Mon Jul 09, 2018 7:50 pm
by ammolab
Since your brass is uniform in length: Your RCBS seating die can be adjusted to seat AND crimp. As you discovered lee factory crimp does crimp when she'll holder contacts the die bottom (sliding collet).

Re: Using a 308 Win Crimp die on 30-06

Posted: Mon Jul 09, 2018 7:54 pm
by ammolab
ammolab wrote:
Mon Jul 09, 2018 7:50 pm
Since your brass is uniform in length: Your 30-06 RCBS seating die can be adjusted to seat AND crimp. As you discovered lee factory crimp does crimp when she'll holder contacts the die bottom (sliding collet).

Re: Using a 308 Win Crimp die on 30-06

Posted: Tue Jul 10, 2018 6:55 am
by RWS
I agree with ammolab but your best results will be obtained if you trim all your cases as close to the exact same length as possible. Otherwise, longer cases may receive too much crimp that can easily cause the case shoulder to bulge where it meets the neck and you can end up with out-of-spec cartridges that won't chamber. This problem can also show up when using mixed cases from different manufacturers. Start with a light crimp and work up to get the heaviest crimp that won't bulge the case.

You can also bypass the crimp altogether by removing the decapping pin and seating boattail bullets. Without the expander ball the neck diameter's I.D. will be small enough to provide a crimp-like grip on the bullet and the boattail will help self-guide the bullet into the case when seating. I have never experienced bullets pushing deeper into the case upon feeding when using this method.

-Bob