Re: Steel Targets and pistols
10 yards is a good measure but doesn't mean you still won't get hit by frags. Especially if you're shooting jacketed bullets.
I've been hit at IPSC matches (enough to draw blood) even though I was 20+ yards back (spectating at the time, not shooting or RO'ng). Never serious in my case. Two friends were hit with enough of a ragged jacket to cause a trip to a hospital to get the copper extracted, wound cleaned, dressed, etc.
That being said, everyone that I compete/practice with for IPSC/USPSA routinely shoot at steel at 10 yards (or farther). We see it as a reasonable risk/reward.
Keep in mind: the more pitted the steel becomes or plate surfaces bending after 1000s of hits, etc. the more frags become likely. Starting with AR500 steel in the first place is probably a wise choice. Most of the frags deflect in a rainbow pattern relative to the plane of the plate face. That's why proximal no-shoots and other targets get plastered with splatter at matches.