Even AR400 should be good for pistol. I've fired thousands of rounds at mild steel with pistol before retiring them to being sacrificial at 200.
If it's truly AR500, you should be fine.
Any time you shoot steel, there is additional RISK involved.
A bullet will explode off a flat surface at approximately a 20 degree angle and thats the reason you angle the face downward. It doesn't deflect it all down.
ANYTIME YOU SHOOT STEEL, you should have a baseball style cap on with the bill facing forward and safety glasses ( preferably wrap around or side shielded).
This will prevent those small fragments from finding their way between your glasses and your eye.
I shoot steel a bit closer than many and have gotten hit by many shards.
My AR500 collection.
2018-10-18_06-55-09 by
poofy27, on Flickr
Here are some mild steel plates we used at various group shoots untill I decided they were no longer safe to use and bought all AR500 replacements except for the 2 resetting popper that were AR500.
group shoot steel by
poofy27, on Flickr
My advice to everyone is to get good steel, shoot at safe distances, wear a ball cap and good safety glasses, do NOT shoot at cratered steel ( this is when a bullet can hit part of a crater and come right back at you).
This experimental test plate was shot a 10 yards from behind steel sheeting with only the barrel and enough to see the sights. Once again, RISK is different to everyone.
IIRC. a 9mm, .40SW, .44mag, X39, 30-30,.308, 30.06, .300 winmag a couple doubles.
2020-01-21_08-11-50 by
poofy27, on Flickr