I had a tough time with my AR as well, turned out my ASC five round mag was dinging my bullets as it chambered each round, 20 round Colt mag, and I was in business, after trying several optics, I settled on the Redfield Battlezone. Nice and bright, also a 3x9x42mm. The small bore of the .223/5.56 makes it very difficult to bore sight by mark I eyeball, well I should say by 58 year old Mark I's, although I do NOT wear glasses for distance, just readers, but that may be changing, LOL.