I learned not to be stupid and fire my SKS underneath one of those covered benches at the local range, it goes up bounces off the damned thing and then hits me right back in the head. Otherwise it will kick the brass about 15 feet up and about 15 feet ahead of the muzzle.
I've yelled at some dumb idiot at the range for throwing his HK91 brass all over a bench rester, of all the 15 open benches at the range he goes and sets up immediately to the left side of the benchrester who had deliberately set up at the furthest end of the range and the HK91 idiot fires off all his rounds rapid fire. After watching a couple empties bounce off the barrel of the benchrester's bolt action rifle and make it nearly back to the shooter of the HK91 I yelled at the idiot to have some common sense, after he moved the brass atleast cleared the bencrester while going through it's trajectory and landing about 40 feet away.