I bought a SMR kit from a guy that was cracked in the same way, he didn't mention the crack in the description. The barrel inlet fit was VERY tight, I suspect he didn't know how to properly remove the barrel and had grabbed the front of the barrel and the forestock above the entry pipe and gave it a hard pull.
The crack was almost 3" long, being primarily a bow maker I know how to fix cracked wood, I used superglue and my fingers to hold the crack closed and aligned while the glue set. After I fixed the crack I soaked the wood on the inside of the barrel inlet at the crack with as much superglue as it would absorb, superglue soaked wood turns into concrete. This crack will never open up again.
After I draw filed the barrel the fit to the inlet was perfect.
The fixed crack starts at the barrel just above the pin and angles down to the left. I bought the kit for $800 shipped, at that price the crack was non-issue for me.
