For those of you with a 223 or 204, the pic below show the rear of the mag box with the spacer protrusion.
The spacer always digs into the stock because of the elevated edges in the mag well.
Rather than completely shorten the spacer protrusion, I just shorten it a bit with a Dremel and then do some stock inletting. I basically remove enough of the hump in the bottom of the mag well to allow the magazine to float. It takes a few seconds with a Dremel.
I enjoy handguns and I really like shotguns,...but I love rifles!