30 carbine bulging

[Mauser48]

Hey guys. I'm in the process of loading 30 carbine ammo with new armscor brass and 110 grain fmj armscor bullets. When I seat the bullet there is too much bulge on some of them. Some just bulge out a little which is fine in my experience but some have a pretty good size bulge. I backed the crimp off and it didn't seem to do much. I tried chambering them in my rifle and if I racked the action really fast it would mostly work but sometimes the locking lugs wouldn't turn in battery all the way. Not sure what to think here exactly. Dies are rcbs steel dies with a Taper crimp. Any suggestions? Thanks!

[SWANEEDB]

I think I would start by mic'ing the bullets and then measure brass wall thickness, if you have any extra military brass, give it a try.

[Denver]

I'd guess that your bullet and case are not in alignment. You may need to change your seating stem to better fit the bullet nose. Also try seating the bullet part way and then rotate the case a half turn before seating the bullet the rest of the way.

[Bmi48219]

Where is the bulge? I was getting consistent coke bottle case bulge at base of bullet. Backed off sizing die a 1/2 turn and it went away.

[Mauser48]

Yep thats where it is. I think your right that it's sizing too much. The ones that you had bulged, did they shoot ok? I just loaded 50 to test out.

[Larry Gibson]

Where is the bulge? I was getting consistent coke bottle case bulge at base of bullet. Backed off sizing die a 1/2 turn and it went away.

That is the solution. I'd back the sizer out a couple turns and adjust it back in to where the bolt closes and turns all the way locking on the sized cases. Did your RCBS dies come with an expander die?

Larry Gibson

[Bmi48219]

They shot good in carbine & Automag 3. Bulge was right below bullet, looked "coke bottle-ish"
i had set sizing die (Lee ) up per directions, it was sizing a little too much. After backing off sizing die they looked good. I've noticed with 30 carbine that case length is critical. The length variation, even in new brass can result in over sizing & over flaring some. Now that dies are set correctly, I check all of the brass with a mike set at 1.285" after sizing. The ten % that won't fit through the mike jaws get trimmed. Since it's a tapered case longer cases will go further into the die and the throat gets sized tighter than short ones. Seems to help. Good luck.