I have been slowly working my way throught "fixing" an off-face Husqvarna from 1890, drawing on lots of advice and information from folks here.
I too found there was a visible gap at top of breech but not at bottom. On closer inspection, this was because gun was closing on extractor, which was about 0,002 inches higher than end of barrels. I filed extractor face down till it was just missing touching breech face. Now I can see no light at all between end of barrels and breech face. Gun now closes with that nice "bank vault" klunk, with a 0,005 soft metal shim on hook.
This gun has no evidence of anything so drastic as preening locking lugs. Actually, the lockup is nice and tight with 0,005 inch shim on hook -- full lockup on back locking lug and sides of locking lugs lightly touch sides of holes they fit into.
Have no idea how long extractor has been higher than back end of barrels. Gun has been used lots and some well done repairs are obvious.
Niklas
