Over the decades S&W has made some truly interesting firearms, and this is one of those. It's a K frame with a full lug barrel chambered in 32 H&R Magnum. These were an offshoot of there K32 Masterpiece which was chambered in 32 S&W Long and was a very popular target pistol. These 16-4s were only produced for a few years and were soon dropped because of lack of demand. Interestingly they are more in demand now then when they were available. Some owners have the chambers reamed out to accept the 327 Federal Magnum which is even a more versatile chambering. These were made in 3 barrel lengths 4",6" and 8 3/8" and all are quite scarce. I was fortunate to pick these up at a LGS this year and all I can say is WOW! My 6" came with a target hammer and trigger, the 4" has the standard service hammer and trigger. This model was one of the very few thought that came from the factory with S&Ws finger groove, Goncalo Alves Combat grips.