+1 on Gil Hebard as source of M41 barrels. Mounting and sighting in the scope was a pain in the rear when I wanted to switch from open sights to scope. So I called Gil and bought a second M41 barrel without rear sight BUT drilled and tapped for scope mounts. Mounted my scope on the new barrel and sighted it in. Now I can switch from open sights to scope or vice versa in just a few second by switching barrels. The scoped barrel stays sighted in too! It works GREAT!
Good shooting and be safe.
LB
ps: My new barrel did not fit properly on my older frame. Called S&W customer service and gave them my M41 serial number. They reportedly made a small dimension change in receivers/barrels some years ago. They paid to ship my frame and both barrels to them, made the necessary dimension changes in new barrel so it fitted perfectly, tested both barrels for feeding and function, and returned the setup to me in approx two weeks. No charge. Thanks S&W!