No U.S. factory loads are going to cause excessive wear on your M29. After all the gun was designed to shoot them! Naturally a gun will need less maintenance if you shoot lighter loads than if you shoot magnum loads exclusively, but it is no big deal if your gun does occasionally need a little work. After all, no piece of precision machinery works forever without some maintenance. If you fire 5,000 round (just to pick an arbitrary figure) through your M29 and it develops end shake, it is a simple and inexpensive matter to get it repaired. Shoot more and worry less!