Find some flat farm land and measure it out. Thats what I do for my 500 YD shooting. I also shoot a 4ft square 1/2" steel plate with 5 sheets of stacked 1/2" plywood behind it. It stops a 168gr .308 round just fine. Most of the time it won't even make it through the steel at that range.
you expect a non-AP round to go through 1/2" steel???