Two things here I think worthy of note;
1st if the bbl hook (hinge) is worn & the breech end of the bbls have moved forward off face this will allow the bolts to go further forward, moving the lever left.
2nd on the other hand if the hinge is not worn & the bbls are tight on face the lever to the left would likely be from bolt wear. In this case shimming the hook would prevent the bbls fully closing which would bring the lever back some to the right, but this would be a false indication.

Miller/TN
I Didn't Say Everything I Said, Yogi Berra