To answer your original question: there is some junk out there, and a lot of bad shooters, as I am sure you have witnessed with all that NRA instruction and what not. I would have thought that simple observation of those on the range might have answered this as poor techniques are easy to spot. That being said, were they rifles or M4gery carbines with standard handguards or were they "target models" with free floated barrels, perhaps heavy and/or stainless? It makes a huge difference. Surely with all that NRA instruction you've seen many AR's that will shoot ragged little holes at 100, 200, and 300 yards, and even shoot well below MOA at 600, right? Armalite, Bushmaster, Colt, DPMS, RRA, Oly, J&T will all shoot dead nuts. I'm sure there is some garbage out there, but all my AR's will shoot well under the size of a quarter, every time, at 100 yards.
Blake
Blake