Introduced in 1918, the Model 51 was developed from patents and designs from John D. Pederson of Pederson Device and Irwin-Pederson fame as a hesitation-locked blowback semi-automatic pistol with multiple overlapping safety features and good ergonomics. Fixed sights, with the two line address and patent markings (1920-1921 with "OTHERS PENDING") on top of the slide, with the serial number on the left side of the frame, "AS" on the trigger guard, niter blue finished small parts, and checkered and riveted grips with "REMINGTON/UMC/TRADE MARK" in circles at the top. Included with the pistol is a black Remington-UMC box with white, black and red labels (hand-numbered on one end label).

Excellent, with 97% plus of the original blue finish, showing some areas of brown patina, mild edge wear and some light handling marks. A few narrow but deep patches of pitting are present around the magazine well. The grips are very fine, with a few light dings. The box shows wear and tear appropriate to age, especially on the edges and corners. Mechanically excellent.