Solved my problem with 100 brass giving the smile in my Delta 10MM

[JONWILL]

I picked up some new manufactured ammo from PPU. It is ok but nothing great.

I got it mainly for the brass. Was having a lot of case bulges at the base with 10.0 grains Bluedot

Changed to Star line Brass and the bulges are completely gone
I noticed the bullets were much harder to insert in the case and probably kept the bullet from being pulled out or pushed into the round

 

[redbullitt]

I would wager the pressure is too high on the smiled ones for one reason or another. Bullet setback like you suggest could certainly do it!

I usually use 800x, so I dont have much experience with blue dot. I do know it has to be pretty pretty warm for my pistol to smile it heavily.

The starline brass may simply be a little tougher, but I doubt that would do it. It could have a bit more capacity and drop the pressure a bit though.

 

[JONWILL]

I think you are right about the bullet pushback in the PPU case

Had a couple without the bulge and the same powder load

 

[d'zaster]

Interesting about the PPU brass. +1 on the starline. I've had no issues loading blu dot. It's the best for 10mm in my experience.

 

[GaryL]

I had issues with setback in 45acp. Some brass just wouldn't hold the bullets well. I switched to MB IDP #4-XD bullets for that brass, and the crimp catches a groove in the bullet just enough to eliminate the issue.

So finding a different bullet type might be an option for that brass.