I got a quote from a local steel distributor for 1/2" thick AR400 (Abrasion Resistant) steel plate for about $37 per sq. ft., cut to shape. I gave the guy an autocad file with an NRA D-1, an IDPA standard target, a small popper and a large popper. The total price for all 4 was about $350 or so. The AR400 plate isn't quite as tough as the AR500 that some target manufacturers use, but I think the extra thickness would compensate.
My fear is, that if we leave these things out at the 100 yard or 200 yard positions... which I almost have to do, since they weigh so much... some hotshot with his .50 BMG will shoot the crap out of them... I don't know how the steel will hold up under those conditions, especially with AP rounds. The range is a private club range, but totally unsupervised.
Does anyone know what sort of penetration a .50 BMG AP round can cause?