I have a Bushmaster XM-15, with the A3 upper. I recently ordered a Larue fixed BUIS. I plan to take off the carry handle, and put on the BUIS as my primary site, until I get some optics. I read over the IBZ instructions at MDAR15.com. However, the Larue BUIS isn't adjustable for elevation. Can I still get it zeroed in properly with just the front site? Any thing I should be aware of that I'm not thinking about?
Also, I read that there were problems with Bushmaster front site posts being to short. Do I still need to get the taller (.040) front site post to use with my Larue BUIS?
One last thing. The range I go to would only allow me three choices for distance to use when zeroing in (45 yards, 100 yards, 200 yards). Which distance should I use, and what will be the elevation difference?
Sorry for all the questions, and thanks for your help.
Robert