My student was firing my Sig P938 using 9mm remanufactured ammo from 3-D Inv. Inc. Doniphan NE when the cartridge split open and backfired. It blew the factory grip on the right side to pieces and she was hit in the face by flying debris. Smoke was coming out of the pistol. I had instructed her to wear glasses but she didn't. The brass cartridge, near the base, had a ruptured split in it. I have never seen this before. I am an NRA Pistol Instructor and NC Certified Firearms Instructor, former Law Enforcement. This could have taken her eye out and was a severe example of not wearing safety glasses. I will never again use remanufactured ammo.