The correct answer is, depends on the shooter and the situation. If you are on a range where you have time to aim in and keep a nice tight position, then I don' t thing that it' s unreasonable for a good shooter to put a 3-rd burst from an M16A2 into a silouette target at 100 yards. But from my experience with the M16A2 where you' re engageing multiple targets in rapid succession and fairly close range, and in during a " final protective fire" when the enemy is anmost in your fighting hole, then accuracy isn' t as good. Burst mode is not stressed much in the Marine Corps, as the Marines have always preferred to teach marksmanship and the " one shot-one kill" philosophy. As a result, it' s pretty rare that the rifle is put into burst mode. Why shoot one guy one to three times when you could shoot three guys once each?

The most accurate automatic weapon I had the pleasure to shoot in the service was the H&K MP5. While my skills were not that great with it, I could keep about 75% of the rounds on target at 25 yards, and that' s shooting one 30rd mag with one pull of the trigger. Most of the experienced SRT guys could shoot 100% into the 5 zone shooting 5-7rd bursts.

Mike