I'm a fan of Smith's K frames. I now have eight various K frames to include four M&P/Model 10 revolvers. For awhile I've been wanting to add a long-barreled Model 10 (I also own a Model 1905 3rd Change M&P with 6" barrel) to my collection. By the fifties the 6" barreled revolver was on it's way out with law enforcement. It just wasn't very comfortable to have a long barreled revolver while sitting in a car. But S&W kept offering the 6" barrel until the mid-eighties. However I don't usually come across them. I let this one sit in the display case at my favorite LGS for a couple weeks and decided I had to get it. Went over this morning and it was still there. Which is what I figured. Most folks don't want a 38 caliber service revolver with a 6" barrel in 2015. Oh well their loss is my gain. Mine was made in 73.It's serial number is D51****.The frame is clearly stamped 10-5 under the crane. Now I need a Model 10 snubnose (2" bl) and also one with the 3" barrel.