Wraco, my 5-inch is C147XXX and shipped December 2, 1950, according to Mr. Jinks. The SCSW says the C277 to C402 range was 1954-1956, so that would put yours a few years later and about right with sabre's date. SCSW also says they changed to the ramp front sight beginnind in 1952, so sabre's comment about that barrel lying around for a while before being put on a frame sounds correct.

In my SCSW, I noticed that all the photos of 2" M&P Airweights had the ramped front sight, but several photos of steel-framed guns made later still had the round sight. Reckon they put the ramped sight barrels on the Airweights from the beginning, and kept putting the older barrels on the steel frames until they ran out? Anybody ever seen a 2" Airweight M&P with a round sight?

Snuffy