I paid a visit to a local indoor range with my relatively new AR for some close in target practice. I was informed that my green-tipped ammo couldn't be used there. It has a steel core and could overpenetrate their backstop. It could also make sparks that could ignite the rubberized pellets banked against the hard backstop. I'd never heard of such a thing but wound up buying 20 rounds of their ammo instead of using the 60+ rounds I had brought. I'll have to get outside somewhere to use mine. Anyone else run into this situation?