BrassMax is a variant of other cartridges produced by TulAmmo that WalMart has been selling for some time. The typical TulAmmo comes in a steel case. I have only seen this is brass recently and only in 40. TulAmmo is actually Russian made. I haven't had significant problems with it, but some of the cartridges seem to be a little weak. It also tends to be quite dirty, with almost a burned smell when shooting. I don't know if it would do any damage to your gun, but I personally won't buy it.