I just got a Sig Romeo 1 with a matching Sig mount on my Shadow1. As previous posts suggests, finding the dot is not as easy as an open sight. I had it dialed @ 20m, so far I am happy. My 1st shot was 2" from the dead center of the target. Succeeding shots, is within 5" group considering my hands are tired due to an ongoing home reno. Bench rested, easy 2" grouping. My only concern is the rather short mounting screws supplied. 6-48 X 5/16, with only few thread turns going inside the mount. I used Loctite Blue Thread Locker to keep the screws in place. Unfortunately, I only had 50 rds into it. So far, so good. I am still trying to find a local source of the 6/48 X 3/8 screws. I can get it from south of the border, but shipping cost is ridiculous. There is a local source, but you have to buy the whole box of assortments to which you only need 2-pcs.