every 12 inches of travel down the barrel.) The M16A2 has a 1:7 barrel twist. (The bullet rotates once for every 7 inches of travel down the barrel.)
The M16A1, with its 1:12 twist, does not put enough spin on the heavier M855 bullet to stabilize it in flight, causing erratic performance and inaccuracy for training or full combat usage (30.48- to 35.56-cm shot group at 91.4 meters and 72-inch shot group at 274.2 meters)(Figure F-15A). Therefore, while it is safe to fire the M855
Figure F-15. Ammunition impact comparison.
Was this article helpful?