Do you have your own land to shoot on when doing the bounding or is that just in your yard type exercise?I'm not very nice to it. The normal bounding, 3-5 second rushes, rough handling. I shoot suppressed now for about 500 rounds. The crack does not go all the way through. Round count is probably in the thousands.
On the hinge, that's a weird spot for a crack. You'd expect it to crack on the other side if it's from impact of the carrier. I can't even see how you would hit the stock and crack just that lip.