I've had 3 20" inch Colt AR's in the back of the safe for the last couple years. I bought them SUPER CHEAP and never shoot them. They were one of those deals in which you really didn't need em, but you couldn't pass up that kind of deal. Well, this past weekend I took them out of the safe and went to my grandfathers 300+ acre farm to have some fun. I was hitting a plastic milk carton everytime at 250+ yards with open sights. I love shooting into a pond at 250 yards because it allows you to see where your bullet path is located. It was a blast popping that can at 250 yards! I'm going to sell some of my 16"s to buy a few more 20"s. I have a couple 6700 flattops that I thought about putting an ACOG TA01NSN on. How do you thing this combo would work on the 6700 20" flattop?