We have a local indoor range that will not allow steel-core ammo as they use a Savage Range system which is a nautilus type structure that slows the bullets; They say the steel can penetrate or severely damage the recovery system. The indoor club I belong to has banned its use because the back stop is Armor Plate from a ship held at an angle of about 45*; the steel cored stuff has caused damage to the back stop. A friend of mines is a certified structural welder, he was able to fill the voids in the backstop. Another club I belong to has no steel backstop only berm and they don't care what you shoot. I have a bunch of steel core 7.62x25 Polish and Bulgarian ammo, it works great in the satellite designed pistols.