I just got a new Colt sp 6920 magpul edition. With the rear flip up sight I like the smallest ring possible when I find my sight picture, so I moved the sight rear sight to the front of the rail. As far as I know it should be fine, but I just wanted a confirmation of that. With the sights being closer I just wanted a second opinion make sure that it's not going to throw off my aim in a way that I can't adjust. I know I might have to re-zero it next time I go to the range.
On another note I found that it shoots amazingly and I am incredibly happy with the rifle.