Macgrumpy: Your post is an argument from authority, and your authority is clearly too incompetent to be taken seriously.
Seriously? Yes, my argument is an appeal to authority (the authority being the DTIC report/U.S. Army Research, Development and Engineering Command) and I feel far safer deferring to their studies, testing, and research than to believe some Internet expert that simply posts opinions with no personal expertise or test results to backup his comments, and who very often misinterprets or takes out of context information from valid resources. Additionally, I have a problem trusting the knowledge of an expert that has had several "slamfires" that could easily be explained by parts failures due to excessive forces from lubricated cartridges.
My first slamfire was in a Garand, heavy NM Douglas barrel, using federal match primers. At the time, conventional wisdom, spread by shooters such as Bart B, were all telling the community that the only thing that caused slamfires were "high primers" and your worn out receiver bridge. My Garand slamfired out of battery during sitting rapid fire. I was not lubricating cases then.
The concept of sensitive primers did not exist at the time, and I was pretty sure all my primers were below the case, but I was not 100%.
My second slamfire was also in another NM Garand, shooting ammunition loaded with federal match primers. I had just received the rifle from the gunsmith, the receiver was cherry, new douglas match barrel, and the rifle slamfired out of battery when firing from the clip. This ammunition had been sized in a Bonanza match sizing die, and I had reamed all primer pockets to depth and seated all primer by hand, inspecting each and every round to ensure that primers were below the case head. At this junction I concluded that convention wisdom that
only high primers and your worn out receiver bridge was bunk.
Since then I have been using the least sensitive primers in my rifles, because, baring mechanical issues, the primary cause of slamfires is primer sensivity. The Garand mechanism has a design defect in that it allows incidental contact between the firing pin and primer, before lockup. This defect was never talked about and deliberately suppressed.
What I am interested to you to explore this idea that
"slamfires" that could easily be explained by parts failures due to excessive forces from lubricated cartridges
How does high pressure cause slamfires? What parts have to break to cause an out of battery slamfire? Before you start stating that hammers or firing break due to high pressures, I am still using the trigger group from the second slamfire incident, no problems, the bolt was OK and the firing pin not broken. I am still using that bolt when the rifle was rebuilt. The first one, I don't think I lost any bolt parts, though extractors often get blown out. I still have the bolt. The trigger was fine and used again as is. I might still have that trigger group because the trigger had an excellent pull, but I did sell that action in a new stock. I remember replacing the old stock, the elevation knob, the action on the first rifle was usable after the gunsmith worked on it. The second one the receiver heel was knocked off.
So, how does high pressure cause a slamfire? What part failures caused by high pressure cause a slamfire?
Or is your major malfunction a case of
"evil things happen to evil people"? Someone you know has a flat tire and therefore they are a liar, untrustworthy, because you, the righteous one, never had an accident? Are you one of those Puritans that believe that the hand of God is lifted from the unrighteous and therefore you can identify the damned by the misfortune that comes their way?
The point about the competence of the Army Ordnance Corp. A sack of potatoes has more intelligence than the average Army Engineer. The difference between potatoes and an Army Engineer is that no matter how long you cook them, the Engineer will always end up half baked.
Did anyone notice this recent Army Scandal?
Missing batteries among issues that caused Army's runaway blimp
http://www.latimes.com/nation/la-na-runaway-missile-defense-blimp-20160214-story.html
The Army report is classified, but pieces leaked out. Someone forgot to put batteries in the auto deflation device. This blimp terrorized the Pennsylvania country, causing F-16 ' to be scrambled as the thing took out the power gird and scared live stock. Eventually Sheriff Deputies shot it down with shotguns.
Seems the $2.00 Billion Jlens blimp had a system failure of the pitot tubes. The altitude control system lost its elevation and than the blimp tilted instead flying horizontal. Winds broke it loose from its moorings. The auto deflation device should have engaged and deflated the balloon but one of those brilliant Army Engineers forgot to put the batteries in. Oops! If you notice, the Army is not really talking about this.
You're correct, the ammunition is proofed according to the standards you quoted, but the point of the test was to recreate the field conditions rather than using optimum lab conditions. That's part of what the study revealed, that the real world conditions were far more severe than anyone expected. One of the articles that I linked to clearly states that the reason the cartridges were tested at 160 degrees is that the barrel of the M249 machine gun actually reaches those temperatures in the field (as those of us that have actually fired that weapon understand). The ambient temperatures in Afghanistan can reach 120 degrees, add to that the increase in temperatures when you've fired several hundred rounds during a firefight and it's pretty easy to see that the entire gun and the ammo will reach temperatures well above the proof temperature.
I guess you did not learn in whatever service you served that firearms have thermal limits. Good thing you did not encounter a human wave attack, such as some of my buddies did in Korea. They told me about the importance of keeping both your ammunition and your machine gun cool. Cooking ammunition to 160 F and then firing it in a 160 F machine gun is going to cause malfunctions. My bud's told me about fire control and burst control. You hold down the trigger and keep firing, and your gun will jam. If not burst in fire.
Took this guy 300 rounds to cause the handguards on his AK47 to burst in flames
https://www.youtube.com/watch?v=eNAohtjG14c
And that is what the Army re discovered. Heat is bad. Weapons and ammunition can over heat. Heat does not magically transport itself into the ether along with that bolt thrust caused by overpressure cartridges. It is apparent, they forgot these things. Just as it is apparent you don't recognize that structures have thermal and structural limits. Didn't they teach about the limits of squad weapons, and the differences between heavy weapons and light weapons, and issues of sustained fire?
Since you are so knowledgeable about these things, just what are temperature ranges in the SAWS Prime Item Development Spec. Maybe you know the number, I have not found either the spec, or a number reference. That should be in the report. I believe the Army lost the spec. They don't have it anymore. What I was told they bought the SAWS as a fully developed weapon, that is, COTS. Whatever procurement documents date back to the 1970's and I will bet that every body from then retired, and every paper file was dumped when the Army went to the paperless office. (Ha!) I am of the opinion the Army no longer knows what technical requirements the weapon was purchased against and only the contractor knows. I remember the 1970's and we were not going to be attacking our Best Foreign Friend (BFF) Saddam Hussein. He was kicking Iranian butt and we were cheering from the side lines. At the time, we were worried about the Russian juggernaut, nuclear winter, and the Russian winter. Contract requirements are very important things, if the Contractor is building SAWS to the Contract requirements, that is, the technical performance requirements in the Prime Item Development Spec (B1) from the 1970's, then any changes coming out of this 160 F test, are added scope. The Contractor will press the Government for hundred's of millions of dollars to redesign the SAWS to the new requirements. Do you have signature authority to commit the American Nation for an expenditure of hundred's of millions of dollars because you want a SAWS to operate at 160 F with 160 F ammunition? Do you know anyone who has that authority? Or are you just some person who wants something, but really does not understand what they are asking for? That is, so incompetent, that you don't realize that you are incompetent? You questioned Mehavey's qualifications?!! Just what are your technical qualifications?
Incidentally, yes, temperatures in Iraq reached 121 once, I have not studied Afghanistan, but certainly 120 is achievable. I have been in the Mohave Desert and that was very darn hot. So, do you expect to fight in 160 F weather? What are the human limits of survival at 160 F? Maybe I should say, you know what to call a human in 160 F heat? : a dead person!! . How long could you survive in MOP IV, in 160 F weather? Ever thought about it?
It is my opinion that the Army showed its incompetence by testing weapons out side of the range of human survivability. They also were clueless about their own temperature requirements, just as you are. Ever heard of Mil Std 810? No, I did not think so. Just what are the operational environments for ground equipment and the storage conditions?. I don't think the Army knows either. They were in violation of their own standards. They exceeded the temperatures they contracted for the weapon and its ammunition.
So, what remedial efforts did the Army take for the SAWS? What hardware changes did they make for the weapon and ammunition to fire full sustained automatic fire at 160 F with 160 F ammunition? If the weapon is defective, what did they do to fix it?