Jeff...
I have a rack and two bars...if I were to pound the stuff together there would be more wear. There's only a bit of flattening of the bumps of the powder-coat of the j-hooks of the rack. I'm going to be attaching some thin vinyl matting to the potential wear spots.
At the smaller-box gym I used to work out at, all the knurling at or about the contact points for a snatch grip were worn smooth on the barbells, mostly the the one they had for their bench press set up.
I've heard old socks work well to protect the racks (and bars).
