Smith & Wesson produced barrels for the Model 41 in 5", 5 1/2", 7", 7 3/8".
There were 2 versions of the 5 1/2" barrel with one having a extendable front sight.
The 7 3/8" barrel had a removable muzzle brake where the 7" barrel didn't have a muzzle brake. If you remove the muzzle brake off the 7 3/8" barrel, there is a 3/8" section of the barrel that extends out that either the muzzle brake sits on, or a false muzzle sits on that are attached with a mounting screw that screws into the end of the internal barrel weight.