Bobster
.30-06
With that said, .40 got a really bad reputation many years ago from a lot of the guns not having a "supported" chamber, especially from that Gaston dude. meaning, that some of the brass case stuck out behind where the mouth of the chamber was...What this allowed to happen is the area behind the chamber would swell or blow up the case when the bullet is fired.
Yes, I would switch to a different ammo...I would also check inside of there to make sure nothing is damaged. Including the springs.
I'm thinking either some double-powdering or improperly resized cases, maybe. Or many times fired cases. In looking at the remaining reloads not fired, some seem a little "fat" around the middle as if not resized properly or fired in a gun with an oversized chamber. I just put a new box of .40 on my "things to get" list.
There doesn't seem to be a lot of overhang at the feed ramp or anything else mechanically that would cause bulging or case rupture. Aside from a little bit of smoke residue, the springs look OK.