Mark - your range experience must not have completely turned you away from Ross rifles. In fact, if I recall correctly I think I saw you bid on a Ross on auction within the last month or two ;)? I have never heard of a bolt blowing back out of any Ross other than the M-10/MkIII. The inside of the bolt is engineered like a "Yankee screwdriver" and it is possible that spring broke in your bolt. I was interested to hear of your rapid-fire experience with the rifle.