I recently picked up a Bushmaster XM15-E2S with CAR stock. It`s got A2 sights which are okay but I`d like to try some optics on it. It`s got a fixed carry handle and I`d rather not have it up way high. How well do the scount type mounts that cantilever the rail down and in front of the handle work? I`m thinking I could top it with a decent red dot and co witness the iron sights through it. Opinions? Marcus