I carry a M&P Shield 9mm. I want to acquire a 22LR as a plinking/practice gun. I want to stay with S&W. I have found what I believe to be 3 22LR guns very similar to my 9mm. However, I am confused because there seems to be 3 variants of this gun. Can someone tell me which one of the S&M 22LR guns compares best (barrel length, action, weight, trigger pull, etc.) with my Shield 9mm?