I'm a little confused here. Could someone please post some shots of the 17 and the 18 in 4" so I may better see the difference. Most of the 17's seem to be 6" with a few 8 3/8" Not many 17's in 4" Also was the K22 more or less the same as the 17? Great site! To be recommended to anyone thinking about a S&W,with all the input from experienced owners and collectors.