I picked up a MK1 in .22 the other day. I usually don't like MK1 Rapids purely for aesthetics. I always thought the stocks were a bit "clunky" looking on the MK1, but this one had (for the U.S) what appeared to be an unusual stock.  Theoben made a Skeleton stock called the "Sporter".  While most of my air gun purchases start out as purely for "re-sale", this one (like the rest) will probably linger for a bit longer than expected.    The combination of nice wood, lighter weight due to the skeleton, etc., made for a lightweight, attractive package.  And since I have a .177 and .20, I could conjure up some reason to keep it. (I'm still conjuring, give me time)

When I received the rifle, I noticed a loud "Pop" coming from the receiver when firing.  If it didn't have the AZ on the end of the barrel, I probably wouldn't have noticed it, but with it, it was very loud with it on. First, I'd like to state that the seller was a true gentleman. He offered a period of time to inspect and return the Rapid, but I declined.

The pop was obviously from the receiver, but I didn't know from where.