I built a set of Rams from 3/4 plate steel. Got it for free off a salvaged dredge hull from work. Faster rounds still make quite a crater at ranges of 500 meters but I have no round that will shoot through it. That would include rounds from a hot 7STW. The deepest hole was from my .240 Weatherby shooting 95gr Bergers at 3400fps. I also used a hardened 1/2 piece of steel to make 5 of each of the other silhouette animals. I believe it was called QT1 or 100. Bought it back in 1998 or 1999. A 4x8 sheet cost me around 800.00 then. Stops rounds readily used for NRA metallic silhouette just fine with no target damage at 200, 300, 385, meters.