I've got an M&P22 compact. It's a fun little gun with my Sparrow on it and it runs pretty well on any ammo I feed it. My only complaint is the trigger pull. It has a LOOOOOONG take up and could stand to be a little lighter.Good to know on 4.5" barrel. I'm thinking that a SR22 with a SpectreII would be a fun little plinker without getting another new host. I really like the S&W 22 compacts; but they seldom come up for sale at a good price.