As promised, a few more photos...
This gun came with the ill-fitting and inappropriate post-1968 magnas you can see in the photos in the first post, but it needs PC diamond magnas to be consistent with the original shipping configuration. I had some non-PC diamond magnas in the woodpile and put them on as better-looking placeholders until I can get the stocks the gun really needs. And because I don't like the basic K-magna handful, I added a grip adapter for comfort.
The entire top of the gun is dulled down and pretty featureless -- a slightly textured matte black on everything, no grooves in the front sight foot or the rear sight base, but a few discreet grooves on the angled surface of the front sight ramp. This is different from later versions of the Combat Masterpiece two-inch revolvers, which had a grooved sight base and smooth ramp.
The 56 is a heavy barrel gun with a wide rib.
The heavy barrel required that the front part of the frame
not be chamfered. Otherwise parts of the barrel would overhang parts of the frame, an ugly and unacceptable proposition.
I cannot see a filed-down spot on the backstrap, but if I close my eyes and run a fingertip over the steel I think I feel a slight flat spot or even slight dish in the contour that is probably where the U.S. stamp was once to be found. (These are the old stocks in this photo.)
And anoher pic of the serial number after I got some crud out of the numerals and replaced it with the dust and fibers that are hallmarks of my photographic technique.
The Model 56 designation has so powerful a claim on the minds of collectors that it is possible to focus on the number and look past a couple of interesting aspects of this configuration. The gun is clearly in the K-Masterpiece family, basically K-frame revolvers with adjustable sights. Before this snubnose design was put into production, the company made the standard K-38 Masterpiece, or Model 14, and the Combat Masterpiece, or Model 15. This gun is a lot like the Combat Masterpiece, but with a two-inch barrel. With the possible exception of some prototypes, the company had not produced such a configuration before the Air Force provided specs for this revolver, which S&W decided to identify with a separate model number. In this, they followed past practice of distinguishing some models based on barrel length, for example dividing the Combat Masterpiece from the original K-38 Masterpiece with a different model number.
The Model 56 is the first adjustable sight two-inch K-frame the company produced. Fixed sight two-inch M&Ps had been produced since before WWII; it was the presence of the adjustable rear sight that made this gun different.
As soon as the Model 56 became a known configuration, public demand began to be heard for a commercial version of the gun. In 1964, a year after completing the Air Force contract, the company introduced a two-inch barrel option as a variety of the Combat Masterpiece. No new dash number was created, and the gun was marketed simply as a variety of the Model 15-2. The Model 56 designation was never used again.
I have not yet had this gun to the range, but hope to sometime in the next month. It is mechanically sound with good bore and chambers, but the backstrap erasure and worn finish limit its value as a collectible. I have no qualms about taking it out for a run.