if the rds are CorBon's 100 gr, 1400 fps (4" barrel) loads. putting 1750 ft lbs and 56 factor momentum into the chest, that fast, is a helluva lot of destruction and shock to just "shrug off".
Its just .17 second repeat hits, not at all that tough to do, at the 10 ft range at which civilians have to fire, with a good SA auto, using a trigger stop. The first hit is not part of the timed event, you see.