I bet you have no clue as to who invented the ar 15 do you
Originally Posted by skirtchaser79411
Eugene Stoner is credited with coming up with the unique gas tube operation of the bolt as opposed to the gas piston/rod actuator found in the M-1 and M-14.
Colt perfected it after buying the design from Armalite.
One of the unique features is a barrel extension that screws onto the breach of the barrel to form the locking lugs that engage the bolt. This allows this criticle area to be hardened to a high RC number to improve wear without compromising the strength of the barrel.