I think thats legaleeze for, "We have our butts covered"!!
We shoot steel spinners at 50 yds minimum with .22lr - steel plate at 200 yd minimum with jacketed centerfire rifle ammo. But I'm a nut for saftey and I've got the scars to prove it.
For in close these work great, or even a wooden block bounces pretty good.
Self Sealing Targets
Good luck, Ken