That is a nickel plated, 8 shot, Registered Magnum.
These were offered exclusively by Lew Horton. 4 variations of the 8 shot Registered Magnum were produced.
In 2006 the first of the 8 shot Registered Magnums went into production. The initial offerings were a 3 1/2" in blue steel and a 5" in blued steel. Production of each was 350 pieces.
In 2007 The second set of the 8 shot Registered Magnums went into production. These offerings were a 3 1/2" in nickel plated steel and a 5" in nickel plated steel. Production of each was 250 pieces.
The photo below contains one of each variation of 8 shot, 357 magnum
revolver that S&W has produced to date. All six revolvers in this set are the same number.
The additional 2 variations offered were a 4" blued steel and a 6 1/2" blued steel that went into production in 2000. 100 of each of these variations was produced. These two were exclusive offerings from Bangers.
All of these revolvers were produced by the S&W Performance Center. Fit and finish is superb. The barrels are match grade and accuracy is simply outstanding. All of the revolver variations have their cylinders cut for moon clips. Each revolver comes with several moon clips and was shipped in a aluminum Performance Center case. Additionally the 4 Registered Magnum versions came with the registration certificates.
These are among my very favorite S&W wheel guns.