Here is why you won't have a bolt failure with the Marlin. I got to looking at the Marlin bolt to see how it could fail, and I don't see how it could. Mossberg, Savage and Marlin all utilize a bolt head that is pinned to the bolt body. Marlin however did design a safety feature into that bolt to insure that the bolt head will always turn with the bolt body in the event of a retaining pin failure.
The Marlin bolt head has a key slot that mates with a detent in the bolt body. Even in the unusual event that a retaining pin breaks, that bolt head will turn with the bolt and safely lock into the locking recesses in the receiver.
So I think you can be comfortable that you will not see a bolt failure in the XL-7
