I've personally shot thousands of MFS' steel-cased 115 grain through my Glock. Aside from the black finger tips you'll get from handling it, I've experienced multiple dead primers (loaded them back into a magazine and restruck it, multiple times), white muzzle flash during low light, and lots of carbon residue in the gun. The stuff is downright dirty. It gives off more smoke than other stuff, too. It's your choice if you want to shell out a some extra for Geco/RUAG, but I have and don't mind the lack of black paws. Having said all that, it works, it's cheap, and since it won't be doing anything more than punching paper or smacking steel, why not? I have not noticed any adverse wear to any of the parts of my firearm (including the chamber) for having used it.