I've got about 35 pieces of steel on my place, all but 1 are made of AR500.
Like taliv, I actually shoot a pistols a lot closer than the prescribed min safety distance, but wear safety glasses and don't sweat an occasional cut. The key I've found is to angle those plates backward to direct the splash down, allow for movement, and use perfectly faced steel. Once steel is dimpled or cratered you'll start getting a significant amount of splashback.
The steel that cannot be angled back due to how it's mounted, gets shot at greater distances.
In this picture you can see one of my plates angled backward on an Arntzen portable stand:
I actually get less splashback from these than my freestanding knockdowns (AR500 Bowling pins and animals) and spring mounted TGTs.
My 8" "lolly pops" are mounted using springs, so they have some give and the stands rock a little:
So in my experience it depends on the quality of your steel, how you mount it, and how much fragmentation you're willing to accept........
Chuck