Had a red fiber optic front sight installed on my S&W 617. The sight is held on with a very small, proprietary roll pin. The new sight needs to be drilled very carefully to accommodate the pin. Definitely not something I could do myself, and my usual guy couldn't do it either. However, I managed to find a gunsmith who did a great job. The only improvement needed on what I find to be the perfect all-around .22 handgun.