If you can’t find the factory part.
Anyone who is not obsessed with the “lowly” .22 rimfire can’t call himself a real gun junkie. You simply can’t have too many .22s. Some of the finest handiwork of the American arms industry handles this little cartridge. Millions of gun owners’ first exposure to firearms came from one.
My first .22 was actually a Savage M24, with a .22 Long Rifle barrel over a 20-gauge tube. My next .22 was an M17 S&W, followed by an M41 auto pistol with a 5-1/2-inch heavy barrel with an extendable front sight. These three guns consumed several cases of .22 ammo before I could vote. In the end, I used the revolver most since it was just handier. To my eternal regret, I never sprung for one of the little lightweight 5-inch “field” barrels for the M41, something that would have put it into the field more often.
In moving back to the old home place, I stumbled across the lovely old M41 which I had not shot in years. It was still a boat anchor so I thought why not find a field barrel, a part long out of production. Poking around on the Internet turned up several but priced at two or three times what I paid for the whole gun. Miffed, I swore to do what any self-respecting gunsmith would do and make one myself from a standard-weight, 7-inch target barrel just as the factory is purported to have done. After a few weeks of searching, a suitably seedy candidate materialized.
Since this project wasn’t something I do every day, a little planning seemed in order. I am a muller by nature and prefer to wrestle with projects in my head over time before making chips (or mistakes). By working in my head while driving, mowing the yard or some other brainless task, I can go through the motions and generally anticipate every step, tool or potential problem. Where numbers and specifications are involved, I’ll even make a few notes or sketches on the back of the proverbial napkin.
Everybody has his own approach to shop projects, but, along with the planning, I like to gather tools and make any fixtures and parts in advance of the real work, in part, because I’d hate to have to tear down a complicated machine setup just to make some little gidget. Any of you familiar with the M41 barrel know there is an extension of the barrel, which covers the slide, leaving the breech face and chamber in about 3 inches from the end. There is no room for a conventional lathe center. So, I made a simple round holder from 3/4-inch round stock which I ran in the lathe collet holder. The closely fitted nub about 3/8-inch long machined on one end engaged the chamber diameter, accurately supporting the breech end of the barrel. A milled flat not only gave clearance with the barrel extension but also served as a dog to drive the barrel. Another small clearance cut was necessary to accommodate the feed ramp. The muzzle of the barrel would run on a tailstock center. The only other dedicated tool I needed was a lathe bit ground to cut the recessed crown.
Hamilton trying out his new, much handier toy. The ratty old
7-1/2-inch barrel has now been shortened into a more
convenient lightweight 5-1/2-inch one.
The first order of business was to shorten the barrel which Ho Chi Minh, the ancient import band saw, did with its usual anti-American violence. With a slab-sided barrel, truing the muzzle in the milling machine was a simple task. Next came chamfering the interior crown with a piloted 60-degree chamfering tool to accommodate the half center. The half center features a small flat on the point of a “dead” center (as opposed to a center running on bearings with the work piece), which reduces coverage of the 360-degree arc of the crown by about 90 degrees. It still provides adequate support for turning but gives access to the face and bore of the barrel to accurately machine the recessed crown. Once cut, I beveled lightly the outer muzzle face for appearance sake.
The remaining rib grooving now ran to the muzzle. On composite S&W revolver barrels, where the base/blade unit is added rather than integral, the rib is slotted and a sight base with a foot is fitted to the groove and pinned in place. You can see the V-grooves in the muzzle face. In this case, there was no raised rib for pinning in a blade, just the grooves. With the heavily sloped barrel shoulder and proximity to the bore, there was simply no way to attractively pin in a sight and then file and polish flush the pin. Silver soldering was out since cleaning solder out of grooves is a pain. A screw-on sight is unsightly which left a slotless, blended screw as the only alternative.
The sight was made from a copy of the old S&W factory add-on sight. The foot was removed and a clearance hole for a 6-40 screw with a 7/32 counter bore cut just behind the blade. Set into a 1/4-inch slot about 0.050-inch deep milled into the rib grooves, the sight has plenty of lateral support. The counterbore was cut shallow enough that the bottom of the screw slot was above grade. Torqued down hard as I dared and set in red Loctite, I filed the head down to just above grade, peened the edges of the closely fitted screw to fill any gaps and then filled it flush. Once the top of the barrel was re-matted, there was no sign of the screw. Shaping and serrating the front-sight blade and a dip in the blue tanks finished the job.
Holding the barrel precisely for the lathe operations (above) would have been impossible without the homemade mandrel. The reconfigured lightweight barrel (below, top item) has a conventional front sight while the 5-1/2-inch heavyweight barrel features an extendable front sight for more sighting radius.
The old M41 is a joy to shoot now with its newfound light and airy handling. Even better, nice to see a few sub 2-inch off-hand groups at 25 yards. Most importantly, the barrel was the result of a nice, pleasant and rare day off in the shop, puttering for my own amusement.
By Hamilton S. Bowen