I made an extra strength wood frame to hang my boiler plate steel (pistol resistant only). I drilled two 3/8" holes in the top corner and bought some bolts and chains to hang it with.
If you can drill holes in it, it is probably not rifle worthy unless you have some serious drill power, and you can hang 'em from my frame.
If you don't have a drill between now and then, we can have Tumbleweed put a couple of well placed 30 caliber rounds through it.
If it is drill resistant, or involves welding, then wait for one of the heavy metal guys to chime in...there are plenty of em here.
General rule of thumb I am working under these days:
--Rifle at least 100 yards away.
--Pistol at least 20 yds, except jacketed ammo about 35yd. Slow bullets tend to form little mini-pancakes, fast bullets self-pulverize into lead dust and copper jackets can bounce back 30 yards.
White spray paint is best, yellow is 2nd best.