I've killed a lot of game and quite a few with Barnes X, TSX, TTSX and LRX. Never an issue with any of them penetrating, expanding or killing. Quite frankly, the op's experience is totally out of character with the performance I have experienced. I'm not sure if Barnes had some issues with a specific lot of 7mm mag or what happened, but my expectation of a Barnes X of any kind would be to zing through a mule deer at 200 yards like nothing, and the deer to drop within 20 yards.
I would not hesitate to load a 7Mag with a 140 Barnes to good velocity and tackle anything in NA.