The M16 didn't come up through regular army ordnance channels. Most rifles/cartridges have a long period of development that originates with specifications put forward by the ordnance people. Stoner's rifle and cartridge was offered pretty much as a done deal from outside the normal channels, and the Air Force bought off on them for their security personnel.
I agree. The Air Forces, Curtis Lemay, saw the rifle demonstrated, was enamored with it and pushed SecDef Robert McNamara into adopting the rifle. Unfortunately, a rifle suitable for security forces is not always the best choice for infantry forces constantly in the field. McNamara made the final call to go with the AR-15/M-16. McNamara was all about standardization of equipment across all branches, despite the unique mission requirements of each service that demanded different capabilities.
The Army then took an interest and (in my opinion) rushed it into production too quickly. It was plagued with problems, some due to the design and others due to changes by the ordnance people - the ball powder for example, was changed changed to a dirtier stick powder which tended to clog the direct impingement design of the rifle.
Not exactly true, and you have ball and stick powder flipped. The rifle as originally designed was to use IMR (Improved Military Rifle) 4475, an extruded or "stick" powder. The US was using granulated, ball powder, in its ammunition. Two problems emerged, DuPont could not produce adequate amounts of the extuded powder to the required specifications, and the military already had stockpiles and industry had production lines that could make adequate amounts of the ball powder so it was switched. Ball powder is dirtier than IMR powder and did lead to increased fouling. This problem was made worse though by LeMay, Stoner and Colt, pitching the new wonder weapon as a self-cleaning rifle, McNamara bought into it and when the rifles were first deployed it was without appropriate cleaning gear or training of soldiers in how to clean it. What were they thinking? "Yeah we'll save money on unnecessary cleaning gear and save time and money on training and weapons cleaning time."
The ordinance people other than the change to ball powder, which was partially based on an inability to get sufficient quantities of IMR powder, didn't cause the issues. The military required, as it did in the rifles currently in service, that the M16 have a chromed bore and chamber. Stoner and LeMay argued this was unnecessary. Ordinance, after testing wanted a forward assist to chamber any partially chambered rounds. Stoner, LeMay and McNamara argued this added to complexity and cost and was not necessary. Had these changes been adopted, as ordinance requested, many of the early issues with the weapon would have been prevented. The only other major change for the A1 was a change in the strength of the extractor spring. In Vietnam it sometimes pulled the lip off stuck cartridges, of course these stuck cartridges would have been much more infrequent had the ordinance departments requested changes been implemented. As it was, after the initial fiasco which led to congressional inquiries and public outcry, the changes were incorporated into the A1.
There have been many, many changes to the rifle since it first came out, most of them revolving around making the rifle more reliable.
Other than the initial changes, which the Army and Marine Corps requested prior to adoption of the original model, very few changes have been reliability based. In the A1 the three prong flash suppressor was changed to the bird cage type because the prongs on the original surpressor were easily bent or snagged on vegitation, and the stock had a well added for holding cleaning gear. The A2 developed by the Marine Corps had a heavy barrel to better dissapate heat, a change to 1:7 rifling twist to match a new heavier round, a three round burst mechanism, further refined flash suppressor/recoil compensator, round vs triangular handguards, and improved sight adjustability. The A3 had the fire selector changed back to safe/semi/auto. The A4 had a detachable carrying handle and incorporated a full length quad Picatinny rail for attaching optics. So you see most changes have been to increase functionality and not reliability. Had the initial Army/Marine Corps requests been acted upon during initial adoption, there would not have been major reliability problems.
Some here will argue with this, but In My Opinion, the heart of the rifles problem from the beginning is the direct impingement system. It vents heat and burnt powder directly into the action and chamber of the rifle. Every other successful design uses a piston in between the gas vent and the action. The piston drives the bolt back and release the heat and gas outside the action. In effect, the M16 is a self-fouling design. It has to be cleaned often and well to work properly.
In a piston design the gas and fouling are just vented/directed to a different part of the operating system. Same problem different area. Gas (heat and burnt powder) is vented off the barrel, into the piston cylinder, pistons do get covered in carbon, stick and have to be cleaned. The biggest problem with the M16 series is that the heat vented into the receiver dries out the lubrication on the bolt/bolt carrier group. I got around this by carrying a bottle of LSA in my helmet band. If I noticed the bolt carrier hadn't moved fully forward (a fairly rare occurrance), a quick squirt of LSA through the ejection port, hit the forward assist, aim, pull the trigger and the weapon ran like new again.
Edited by USMCPrice, 09 August 2015 - 11:29 PM.