I picked up a AR500 Steel pop up target. It says it's to be used with lead or copper jacketed lead core bullets only, and not steel core or steel jacketed bullets. I have some Wolf steel cased ammo, but the only things their web site says about the bullet is that it's FMJ. Does anyone know if their bullets are safe to use on this target without damaging it? Obviously, if I'm not sure I won't use them.