The shallow drilled hole is where the takedown screw engages the barrel as evidenced by black marker.
With the action closed and the barrel set into the receiver (not tightened) there is a gap of .011" between the receiver and the barrel.
Using a feeler gauge I measured the distance the breech of the barrel protrudes through the back of the receiver and it's .042".
Certainly seems to me that the barrel isn't original to this receiver.
bobw wrote on Nov 7
th, 2021 at 11:10am:
It very possibly could be the link, especially since you said the pins are tight. Someone may have gotten the length off when doing that work. But changing the link would probably not be my first choice in diagnosing the problem.
Since the barrel appears to have been messed with, the first thing I would do is see where that retaining screw is contacting in the pocket. You can measure it if you have the correct tools but it would be easier to color the pocket black with a marker, install the barrel, tighten/loosen the screw a few times, remove the barrel and see where it’s contacting. If it is fitting into the partial pocket, you would then need to determine if is will adequately hold the barrel in place.
Back the lever situation. Does the breech block set higher when closed, with the barrel loose? When the block is closed it is captured between the barrel and frame. The last little bit, of block movement on closing, is the wedging between barrel and frame. My point here is that the barrel shank shortening, at least for me, would be easier than anything else. Of coarse that requires a lathe and probably a deeper chamber to get the head space correct. There are possibly a couple issue with shortening the shank though! One, will the block face be square with the barrel shank when closed and second, where will the firing pin strike the shell case.
I am still wondering where the barrel sits against the frame when just pushed back against the closed breech block? Is there a gap?
Bob