41
I recently tried a 22 short conversion on an A550XXX series gun, i could not close the trigger guard, another friend that I sold a similar 41 conversion to, had no issues using it on his A600000 range gun.
This is only the second time I have had the problem.
S&W told me that barrels needed to be fit to the guns, they were never intended to just swap out. Which is so hard to believe, since 98-99% of barrels I have tried worked just fine.
My other failure to mount believe it or not was a 5 inch Sport barrel.
which would not mount to any early or later framed gun.