Is there a good, cushiony butt pad for this? I'm a slim-build guy with not a lot of padding on my bones, making my .308 not as much fun to shoot as it should be. Can't find anything through Google search except pads for AR-15s. But as the photos of my two rifles show, the rear of my .308 stock has a concave profile vs my Bushmaster M4's slightly convex shape. Might there be a pad where this difference wouldn't even matter? It seems the empty space created by the slightly concave profile might actually enhance the cushion effect, but don't know if it would present a mounting or fit issue.