Selecting the proper steel wasn’t an afterthought—it was the only thought. And after comparing the two basic categories of steel, one was clearly a better choice for building targets. The first type, surface-hardened steel, is chemically treated for hardness on the surface of the plate only, whereas through-hardened steel is treated throughout the entire plate. Take AR 500, a surface-hardened steel developed to make bulldozer blades ‘abrasion resistant’ (thus the name). With a Brinell rating of 500 for the surface only, it craters with ordinary use. On the other hand, our through-hardened Rifle Grade is rated between 535 and 540 and performs without cratering under extreme training conditions. We’re not alone in vouching for all these ratings–they’re also certified by the U.S. steel industry. Selecting the proper steel was one of the most important decisions we ever made, but once we did our homework, it turned out to be one of the easiest.