.Can't seem to attach the pic. but a .40 split at the rim.. seems no damage to the gun or me. But WILL NOT use this vendor ever again.
Post a pic, please. If you want, email it do me and I'll post if for you because I'm confused; where did the case split?
A split case mouth - at the open end where the bullet seats - is no big deal and might not be the manufacturer's fault. I've seen factory name brand ammo split so this wouldn't concern me at all and wouldn't affect my opinion of the manufacturer. I'd just chunk that case in the trash and carry on.
If it's really a split rim, as in the back end of the round blowing out or the case head separating, is dangerous and the manufacturer would probably appreciate your feedback. I know I would if it was my ammo.
.....
I put each round in MTM ammo box headstamp facing up and grab a colored Sharpie felt tip pen and run a stripe down each headstamp/across the primer. The colored stripe differentiates your brass from someone elses at the range and depending on the color system you come up with, can tell you how many times a particular case has been loaded.....
Well the rumor goes: 40 S&W should never be reloaded to factory pressures as the cases most likely were fired in unsupported Glock barrels. The cases tend to stretch/weaken in the webbing making it a good spot for a blowout. Not sure if I believe it or not, but 40 S&W hits some crazy pressures as it is.