It's been pointed out that the 2" K frame I remember being issued as a C-130 pilot in the 1987-1992 timeframe may have been an M56 rather than an M15. Perhaps so, I can't recall for certain. I did read in Supica's book that the M56 guns were made in 1962-1963 for USAF. The ones I drew from the armory were in pretty darn good shape and if they were 25 years old then, well they had not been to Vietnam! Maybe 15, maybe 56, I don't know. I would be very happy with a 2" M15 for myself though as the now very rare M56s are quite expensive...most were destroyed apparently!!