I got my Bushmaster AR about two months ago. It is a A2 with the 20" barrel. I really love this rifle, it has been 100% reliable so far with approx. 500 rounds through it.
When I first got it, I sighted it in as the instructions said. Well, I'm here to tell you that it might work for a battlefield zero, but it is crap for target shooting or general plinking.
So today I took it back to the range and sighted it in at 100 yards, two clicks down from 300. It is usable at 50, and dead on at 100 and one click up from the bottom is good at 200.
But my main question is about group size. The Win. Q3131 is grouping about 1.5" at 50 yards and about 3.5"-4.5" at 100 yards. At 200 it was, well, everywhere.
I had some Black Hills 69gr. Match HP with me and it was one hole, .5", at 50 and about 1.25" at 100. At 200, three shots went into 2", but the last two blew the group out to 3.5".
The suprise of the day was the Wolf ammo. I bought my first box ever today just to try. I only shot it at 100 yards and 200 yards. At 100 it was shooting into about 1.5". At 200 it was shooting about 4". I thought that was pretty good for $2.50/20 junk ammo.
All groups were shot with iron sights.
So what is acceptable to the folks at AR15.com? You folks have a heck of alot more experience with these guns than I do. Give me some feedback.