I don't know about Glock, but the Springfiled and Ruger boxes have the same warning. It is the Lawyers talking... in case you blow yourself up with a double charge or something. As for Springfield, it has nothing to do with warranty. I just sent my 1911 Micro Compact back for ejector issues after a long converstaion with the factory rep about what type of ammo I had tried. This included various handloads (including lead projectiles) and they even paid the shipping even though I had purchased the gun used.