Manufactured in 1954. This is a pre-Model 12 Airweight revolver produced on government contract for the U.S. Air Force, who designated it the Model 13 Aircrewmen and requested the revolvers be stamped "M13". They were intended for use by strategic bomber crews for use as survival weapons. Weight conscience, they were originally produced with a lightweight alloy frame and cylinder with a steel barrel. The model was rejected because of problems with the alloy cylinder with most destroyed by the government or S&W. The top strap is marked "REVOLVER, LIGHTWEIGHT, M13". Serial number "C299686" on the butt of the frame with matching numbers on the underside of the barrel, backside of the extractor, and back side of the six shot alloy cylinder. Back strap marked "PROPERTY OF U.S. AIR FORCE". The checkered grips have S&W medallions, with matching number inside the right panel. This revolver falls within the accepted Aircrewman serial range of C247000-C405363 ("The Standard Catalogue of Smith & Wesson" by Supica and Nahas, pg 147).