Ooh yeah, lookit that. It appears AR500 has about 0.30% carbon, plus some hardening-helper alloying elements. It's in the hammer range of hardness. Brinell 500 is around ~51-52Rc. And apparently it IS abrasion-resistant, but probably not compared to blade steels. It's telling that they measure it on the Brinell instead of Rockwell hardness scales. Bullets are measured with Brinell, so that makes sense.

Getting a perfectly even heat, quench, and temper on large pieces is probably part of their trademark process, btw. Heat-treating a knife-sized piece of 10XX is one thing... heating a 1/4"+ PLATE is a whole different scale of problem.