An Evaluation of the Hitting Performance of the M16A1 Rifle with and without a Sight Rib

A field evaluation was conducted of a sight rib designed by the author to improve the pointing qualities of the M16A1 and M16A2 rifles. The sight rib is an integral part of a new upper handguard and bridges the space between the front sight assembly and the carrying handle. It is parallel to the rifle bore and creates a strong visual cue as to where the barrel is pointing. Past firing tests have indicated that such a cue would improve a shooter's ability to hit targets quickly when there is insufficient time to aim properly. Twenty seven combat arms riflemen participated in the evaluation. They fired at pop up E silhouettes emplaced in a fan at both 30 and 75 meters. The targets were presented for 2 and 3.5 seconds. Both range and exposure time were varied randomly. The test participants fired with both standard and sight rib equipped M16A1 rifles using both aimed fire and pointed fire techniques. Time to fire and hit or miss data were gathered for each target presentation so that the data could be graphed too show cumulative percent targets hit as a function of time. The results indicated that the sight rib on the M16A1 rifle significantly improved the soldier's ability to hit a target when the target is exposed briefly or the shooter fires quickly. Originator-supplied keywords include: M16/A1 Rifle, Small Arms, Quickfire, Sight Rib, Infantry Rifle, Pointed Rifle, Rifle Evaluation, Human Factors Engineering, Rifle Aiming Performance, Soldier Firing Performance.