Found an old (L serial#) Bushmaster A2 HBAR the other day for cheap and thought, "Oh what the Heck, one more AR won't break the bank." Decided to keep it iron sights since all my other toys have glass and quickly discovered that I could see the target but not the sights OR I could see the sights but not the target depending on which pair of glasses I was wearing (and without them I couldn't see the sights or the target!). Went online and picked up a Primary Arms Micro Dot (2 MOA) and set it up as an Absolute Co-Witness and Voila! I could actually see the target AND the top of the sight post! Setting up at 25 meters for a Battle Sight Zero it put every round through a 3/8" hole, at 100 and 200 yards it easily held 2 MOA. I've never tried the Red Dot/Iron Sight combo before and wasn't sure I would like it but I soon remembered why I liked having a lighter rifle for the simple fun of shooting it! Only problem now is coming up with enough ammo to keep it fed!