The previous two stories set the stage, for a look at a report drafted for the Army Research Institute for the Behavioral and Social Sciences the Army was still pursuing the “best” (an upgraded M16 meeting all Army objectives) instead of the “good” (the M16A2, which was developed and revised to meet Marine objectives). Of course, we all know the spoiler aleady: the Army accepted the Marine M16A2 as is, leaving the report as an orphaned artifact. The report is here: http://www.dtic.mil/dtic/tr/fulltext/u2/a168577.pdf
Colt factory shot of the M16A2. The A2 was developed by the USMC, but was manufactured by Colt and FNMI.
This is the third of a three part series. In the first part, Thursday on WeaponsMan.com, the Army contractors noted the specific solutions implemented on the A2 and the problems the Marines solved thereby, but complained that the problems and solutions were too USMC-specific. In the second part, posted yesterday, we discussed just what they thought was wrong about the Marines’ product. In this, third, part, we’ll list the modifications that they suggested in lieu of or in addition to the A2 mods.
Reliability
We should note that the Marines’ tests, as reported in this document (p,7), demonstrated significantly lower reliability, and increased fouling in the A2 compared to its older brother. These tests are suspect because the early lot of XM855 used was considered bad ammo, but the M16A1 did outperform the A2.
Thirty Ml6A1 rifles firing 26,010 rounds of M193
Failures to fire – none
Failures to feed – 3 (Not locking magazine in place)Thirty M16A2 rifles firing 26,010 rounds of XM855
Failures to fire – 52 (27 – bad ammunition) (25 – mechnanical [sic] malfunctions)
Failures to feed – 3 (Improperly loaded magazines)
Those failures to fire that were not attributed to bad ammo were thought to be caused by the A2 trigger system’s Achilles’s heel, the burst trigger mechanism. The A2 performed even worse in a cold weather test, but again, it was with the questionable ammunition, and many of the failures to fire were also laid at the feet of the burst mechanism.
The report has an interesting discussion of the burst mechanism and its rationale in Marine, but not Army, small arms doctrine:
The M16A2 has less combat capability due to the elimination of full automatic fire. Full automatic fire enhances the ability of Army units to clear and defend buildings, to conduct final assaults on enemy positions, to defend against an enemy final assault, to conduct an ambush, to react to an enemy ambush, to engage an enemy helicopter or fast moving vehicle, etc.
While the Marines claim greater accuracy and conservation of ammunition for the 3-round burst control, no data were generated during the test to support these contentions and no supportative [sic] data are known to exist.
Also, it should be noted that room-to-room fighting was conducted with blanks, no close-in firing was conducted, no firing with short time limits was conducted, no firing at aircraft was conducted, etc. In other words, for all of the automatic/burst firing conducted during the test, a semi-automatic mode of fire would have probably resulted in a greater number of target hits.
Finally, to be given very serious consideration, is the fact that the burst control requires nine (9) new parts in the lower receiver, evidently contributing to the large number of weapon malfunctions during testing of the M16A2.
They also took issue with the heavy barrel (“heavy in the wrong place”), the twist rate (preferred 1:9), stock length increased when even the A1 stock was too long for small soldiers, and the fast twist’s incompatibility with the .22 subcaliber system.
The article includes an extensive comparison of the pros and cons of Marine KD vs. Army Trainfire marksmanship modalities. These training differences result from the different combat envelopes for the rifleman: the Marines need to engage with rifles in the 300-to-800 meter space, because they don’t have the supporting arms that the Army can count on, at least, not in the same quantity. A unit that must fight with just its organic weapons needs to get the very most out of these weapons. The Army of 1986 did not consider a 500 or 600 meter target a primary rifle target, but a crew-served-weapons target.
In the end, the recommendations the contractors made were mostly about the sights. They put their recommendations in a table with the M16A1 and M16A2 stats. Since the latter are probably familiar to most readers, we omit them now to save time, and just show the contract recommendations.
| Item | Recommended |
| Front sight (day) | Fixed blade, 0.090″ |
| Front sight (night) | Luminous dot on each sightguard |
| Rear Sight (day) | single 2mm peep. A single elevation knob marked for 200, 250, 390, 25, 400, 500, 15, 600, 700, and 800 meters. Windage knob at rear. Each click equal to 1 MOA |
| Rear Sight (night) | Two luminous dots on upper portion of receiver (or a single flip- up luminous dot located forward of the carrying handle) are aligned with front dots for shooting at night |
| Zero Recording | Yes |
| Zero Inspection | Yes |
| 25m setting (day and night sights) | Yes |
| Mechanical Zero | Yes |
| 250-m battlesight | Yes |
| Firing mode | Semi and Auto |
| Barrel | 20″. Slightly heavier than A1 at receiver and mid-barrel. 1:9″ twist |
| Handguard | Same as M16A2 except held in place with a securely fastened ring nut to provide rigidity. |
| Buttstock | Same material as M16A2. Same length as M16A1. Option for adjustable length. |
There are several interesting observations to make here. First, the contractors recommended that the Army make changes that would decrease the mechanical accuracy of the proposed M16Ax relative to the Marines’ A2. Specifically, these changes included the wider fixed front sight blade, the 1-MOA adjustments on the rear sight (A2 offers ½-MOA), and arguably the simplification of the rear sight. The trade-off was simplicity and ease of training, instead of superior bullseye performance.
Second, some of the proposals would definitely improve the utility of the firearm, including restoring the short stock, or replacing it with an adjustable one; increasing the barrel diameter towards the chamber rather than the muzzle, thus improving sustained fire accuracy and reliability; reverting to automatic fire from the burst mechanism (which also has side benefits, in improving the trigger’s feel and consistency). The night-sight proposal was truly ingenious.
Third, in some of these road-not-taken proposals, the Army was reverting to the original AR-10 design and rejecting changes that were largely imposed on the AR design by the Army in the previous decade. These include the rigid fastening of the handguard, and the fixed front sight blade.
Finally, these proposals were almost the last gasp of the iron-sighted military rifle. As this document passed from the contracting officer to file cabinets across the service, without action, special operators were already wringing out scopes and single-point sights, and a few visionaries were already arguing that the day of the iron sight had run its three centuries, and was now at an end. A new generation of optical technology was eliminating the two objections that had kept optics off the rifles of most soldiers: less durability than irons, and slower target acquisition. Many men’s efforts went into winning over the Voices of Experience who still said “no” to anything with a lens, thanks to memories of Uncle Joe’s elk lost because his scope fogged up, or the VC that got away because somebody attached an unauthorized 4×32 Colt scope to the carrying handle of his M16.
This entry was first posted at weaponsman.com
