Smith & Wesson Model 48 (K-22 MRF Masterpiece) .22 Mag. Revolver

By the Guns and Shooting Online Staff

S&W Model 48-4
S&W Model 48-4. Illustration courtesy of

The Model 17 K-22 Masterpiece .22 LR revolver was Smith & Wesson's finest double action (DA) rimfire revolver and, along with the Colt Diamondback .22, probably the best rimfire target revolver available anywhere. A version of the K-22 Masterpiece revolver is still offered today, as the Model 17 Classic.

This article is about the Model 48 K-22 Masterpiece, which was simply a Model 17 chambered for the .22 Winchester Magnum Rimfire (.22 Mag.) cartridge. Most gun manufacturers do not change model numbers when the same gun is chambered for a different cartridge, but S&W does, creating some confusion about their line. Incidentally, S&W called the .22 WMR the "22 M.R.F." (Magnum Rim Fire) and stamped the barrels of their Model 48 revolvers accordingly.

Winchester's original .22 WMR ballistics called for a 40 grain JHP or FMJ bullet at a muzzle velocity of 1550 fps and muzzle energy of 213 ft. lb. from a 6.5 inch barrel. This made the .22 Mag's JHP bullet a devastating small game, varmint and small predator handgun cartridge out to around 100 yards, with a flat trajectory to match. Compared to the .22 LR, it had the punch to anchor larger and tougher animals, such as jack rabbits, marmots, foxes and coyotes, much more reliably and at longer range.

When Winchester/Olin introduced the hot .22 Mag. cartridge to the public in 1959, they apparently did not consult with S&W. However, for years the Springfield, Mass. USA firm had been building and selling their fine Model 17 K-22 Masterpiece target revolver, chambered for the .22 LR cartridge.

Like the K-32 and K-38 centerfire target revolvers, the K-22 Masterpiece was built on S&W's .38 caliber size K-frame, so strength was not an issue. It was only necessary to lengthen the Model 17's cylinder chambers to accept the longer (and slightly fatter) .22 WMR cartridge and increase the barrel's bore diameter from the .22 LR's .222 inch to the new .22 Magnum's .224 inch. (The same bore diameter as centerfire .22 cartridges.) The Model 48 was otherwise identical to the Model 17.

The Model 48 K-22 MRF Masterpiece was introduced in May 1959 and, presto, S&W had a first rate .22 Magnum hunting revolver on the market. It was offered with a four, six, or 8-3/8 inch barrel, with six inches being the most popular length.

All S&W Masterpiece models were carbon steel target revolvers with a 1/8 inch wide Patridge type front sight on a raised and grooved, full length barrel rib and a micro adjustable (for windage and elevation) rear sight. They came with carefully fitted actions, a double latch cylinder, grooved target trigger, grooved front and back grip straps and checkered walnut Magna grips.

S&W initially cataloged a convertible M48 with an extra .22 LR cylinder. However, swapping cylinders on a double action revolver is not accomplished in seconds without using any tools, as it is with a single action Peacemaker type revolver, and the convertible option was quickly discontinued with very few produced.

The Model 48 Masterpiece was manufactured from 1959-1986. During that time there were five minor engineering changes and the revolvers are stamped accordingly on the frame inside of the cylinder crane (Model 48, 48-1, 48-2, 48-3 and 48-4).

Our sample is a Model 48-4. The -4 was the last numbered engineering change and it moved the gas ring from the yoke to the cylinder. This change was introduced in 1977. The first years of M48-4 production were the last when S&W revolver barrels were both screwed and pinned in place. Our gun was made in 1980 and S&W dispensed with pinned barrels in 1982, as an unnecessary manufacturing expense.

Our test gun was acquired from a casual collector in the box, unfired, just as it was originally sold. He apparently bought the gun, put it on a shelf and never got back to it. It came with the paperwork, all accessories (cleaning rod, a small screwdriver, etc.) and still coated with factory preservative. It was quite a find!


  • Type: DA revolver
  • Caliber: .22 Magnum
  • Cylinder capacity: 6 rounds
  • Barrel length: 6 in.
  • Sights: Fully adjustable, Patridge type
  • Sight radius: 7-9/32 in.
  • Metal finish: Bright bluing
  • Grips: Magna style checkered walnut
  • Wood finish: Lacquer
  • Overall length: 11-1/8 in.
  • Weight: 39 oz. (6 in. barrel)
  • Country of origin: USA
  • 1980 MSRP: $209
  • 2016 Fjestad's value: $895 (100% condition)

The first order of business, once our K-22 MRF Masterpiece was in hand, was to rid it of the long since gummed-up factory oil and grease. This was accomplished, as best we could without complete disassembly, by removing the two grip panels and thoroughly sluicing the action with Prolix (a potent cleaner, lubricant and protectant). After cleaning, the cylinder opened and turned freely, a considerable improvement.

Careful inspection confirmed that the frame is straight and the barrel is true to the frame. (Sadly, not always the case with S&Ws of this vintage.) The barrel has a gentle, straight taper from frame to muzzle. It measures 0.715 inch in diameter immediately in front of the frame and 0.593 inch at the muzzle. The muzzle is crowned to protect the bore, without undue tool marks.

Like all S&W double action revolvers, the cylinder rotates counter clockwise, or out of the frame. This is why they need double cylinder latches, one at the front of the ejector rod and the other at the rear of the cylinder.

When cocked, the bolt locks the cylinder firmly in place, without play. Indexing is precise and the barrel to cylinder gap is consistent and very tight. The chambers are recessed to fully enclose the cartridge case rims.

The hammer is powered by a long, flat mainspring inside the grip frame. There is a small tensioning screw located in the lower part of the front grip frame. Screwed all the way in at the factory, we loosened this screw about one full turn to make the hammer slightly easier to thumb cock.

Our RCBS trigger scale measured the single action (SA) trigger pull at five pounds with one "tick" of creep and almost no over-travel. It actually feels lighter, but that is what it measured. Modern auto pistol shooters would think this trigger is wonderful, but as experienced revolver shooters, we know better.

The trigger pull of a fine target revolver should be about half that weight and completely smooth. Unfortunately, by the time this revolver was assembled (1980), internal action parts were no longer finished and fitted to the standards observed when the Wesson family owned the Company.

The DA pull was unmeasurable, since our scale only goes to eight pounds, but it is probably on the order of 13 or 14 pounds. The DA trigger pull is actually immaterial to a hunting revolver, as it is manually cocked before firing.

A firm push on the hand ejector rod lifts fired cases well clear of the cylinder. The firing pin impression on fired cases is uniform and positive, without being excessive. Functionally, everything works as it should.

All of the external metal surfaces of the barrel, cylinder and frame are highly polished and S&W bright blued, with the top of the frame and barrel rib matte finished to prevent glare. This is one of the best finishes in production handguns. However, with the cylinder swung open, one can see that the inside of the frame window only got a coarse polish; ditto the underside of the barrel normally hidden by the ejector rod when the cylinder is closed.

In traditional S&W fashion, the hammer and trigger are attractively color case hardened, rather than blued, for a bit of subtle contrast. The top of the hammer spur is aggressively machine checkered, with the tip of the diamonds left sharp. Flat topped diamonds would be less abrasive to the pad of the cocking thumb.

Model 48-4 revolvers came with S&W's Magna grips, one of the poorer attempts at revolver grip panels. They do not fill the space behind the trigger guard and they do not enclose the grip frame. The grip shape in cross-section is essentially a square with rounded corners, which is a poor match for the oval shape of a partially curled human hand. Fortunately, the .22 WMR cartridge does not kick hard enough to make the poorly shaped grips a problem. For a high volume shooter, a set of Pachmayr Presentation grips is the easy solution.

The Magna grips are adorned with very coarse, machine cut checkering surrounded by a border cut so deep it is better described as a trough. The gloss lacquer finish is attractive, but not very durable. The Magna grips only redeeming feature is that, being made of walnut, they look nice.

Since 1965, when the Wesson family sold the Company to Bangor Punta Alegre Sugar Corp., S&W has gone through several management and ownership changes and their manufacturing precision and quality control has been variable, to say the least. Unfortunately, not all S&W revolvers, even top of the line models, are created equal. Fortunately, our Model 48 appears to be one of the good ones.

The Model 48 was discontinued in 1986, by which time Smith & Wesson had definitely fallen on hard times. Product quality, and most of all quality control, had declined alarmingly, along with sales. Bangor Punta had essentially run the Company into the ground and in 1984 Bangor Punta and its subsidiaries, including Smith & Wesson, was acquired by Lear Siegler Corp., primarily an aerospace and automotive firm.

Two years later, at the end of 1986, Lear Siegler became the victim of a leveraged buyout led by Forstmann Little and Company and Smith & Wesson became the property of the new Lear Siegler Holdings Corporation, which quickly looked to divest itself of "noncore" assets, including S&W.

Nevertheless, in 1989, the stainless steel Model 648 was introduced with a six inch, full under-lug barrel reminiscent of a Colt Diamondback. (A "6" prefix denotes stainless steel construction in S&W model numbers, so the Model 648 is a stainless steel Model 48.) This variation was produced until 1996.

In 1997, S&W was purchased by Tomkins PLC, a British owned conglomerate. In 2000, Tomkins signed the notorious agreement with the Clinton administration that made Smith & Wesson the pariah of the US firearms industry and sparked a consumer boycott of S&W products that endures to this day among shooters old enough to remember the betrayal. However, Tomkins did attempt to improve S&W's product quality, which by this time had been a festering problem for over a decade, by instituting improved production methods, improved product testing and better quality control.

In 2001, Saf-T-Hammer Corporation purchased Smith & Wesson from Tomkins. The following year, Saf-T-Hammer restyled itself as Smith & Wesson Holding Corp.

In 2003 the Model 648-2, a Model 648 version with an internal safety lock that was heartily disliked by shooters, was introduced. The 648-2's short production run ended in 2005.

The new Smith & Wesson Corporation has been racked by successive management scandals, turnover, controversy and patent infringement suits, while simultaneously attempting to license (some would say "whore") the S&W name to products totally unrelated to firearms. However, they have also attempted to expand and improve the S&W firearms line.

Part of the latter effort was the introduction of the Classics line of, "coveted models . . . enhanced with modern advantages." The Model 48 Classic revolver was introduced in 2010. This is essentially a re-creation of the Model 48 K-22 MRF with a four or six inch barrel (sans under-lug). To our rather jaded eyes, the traditional Masterpiece guns, without the under-lug, are how a Smith & Wesson revolver should look and the Classic is in this mold. The Model 48 Classic remains in the line in 2016, as these words are written, so at least a clone of the original K-22 MRF Masterpiece lives on.

Note: An expanded version of this article, including shooting results, is available on the Product Reviews index page.

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