In a normal situation, case heads separate in the M249 when the chamber pressure reaches 90,000 PSI. Normal M855 has a chamber pressure closer to 70,000 PSI when the propellant is heated to 160 degrees, the typical temperature of a M249 barrel after firing a few rounds, which eliminated temperature as the primary factor in these case failures. The next idea was that excessive lube was affecting the headspace and compressing the cartridge, but it was determined that if enough lube was involved to affect headspace then the bolt would fail to lock and the firing pin would not strike the primer.
The author of this is so incompetent he does not know he is incompetent.
This is based on an Army coverup of long standing. Blaming oil and grease for Army Ordnance incompetence is story that goes back 100 years, if not more, and it is a tale that twists and turns as the Army Ordnance Bureau bends it to the needs of the day.
Over 100 years ago the bullet jackets used in service rifle ammunition fouled something awful. Removing cupro nickel fouling is extremely difficult. I had cupro nickel fouling with Iraqi 303 Ball, and after three weeks of soaking with Sweets, I got the lumps to smooth out, but not disappear. Cupro nickel fouling is extremely hard to remove and it ruins accuracy. Period shooters found that dipping bullets in grease absolutely, positively stopped cupro nickel fouling. This is an ad from the era, selling axle grease in a tin, for shooters to dip their bullets.
I have duplicated the same with modern greases and hair gels, just to see what happens.
At the same time as all of this, the US Army is making 1,000,000 low number Springfields in factories that don’t have temperature gages. The only pyrometer at Springfield Armory is used for making springs. No where else in the factory is their evidence of temperature gages. This is particularly important in the forge shop where workers are paid piece rate. Being paid piece rate, the workers had a perverse financial incentive to heat billets extra hot, in order to stamp them out faster. When factory owners create financial incentives for the workers to produce junk, guess what what makes it to final inspection? Currently there is a TV program called “Forged in Fire”, and you regularly see skilled knifemakers over heat their billets as they attempt to forge a knife blade against time. I don’t know a n episode where you don’t see gaps in forge welds, delaminations, cracks, burnt steel. Based on late 1920’s tests, about 33% of the Army low number receivers are structurally deficient , due to poor steel, forge shop burning, and over heating during heat treatment. I have read a 1917 Watertown Arsenal report, rifles were going out the door whose receivers were never heat treated. Springfield Armory was a ship that leaked through every seam.
The Army never admitted any fault. Like all large organizations the Army never admits fault, is highly manipulative, grandiose, self centered, egotistical, no guilt, no shame, is amoral, considers its work force disposable, and you can only have a master/slave relationship with it.
So, whenever a low number Springfield 03 blew up with service rifle ammunition, the Army did not accept that there was something wrong with their rifles or the ammunition, it had to be something the user was doing. That something was greased bullets. The Army claimed that grease got in the chamber and caused increased bolt thrust. And then, the increased bolt thrust caused the receivers to fail. Many of these low number Springfields are so brittle that they will shatter if dropped on a concrete floor, they are dangerous with issue ammunition, the increased bolt thrust argument is a red herring. Ignored by believers, is the number of foreign countries who issued ammunition with greased bullets. I have found that Austrian steel jacketed bullets were greased, Italian steel jacket, Russian steel jacket, and if you have ever shot any, Swiss ammunition was issued with greased bullets up through 1978.
The pre WW1 Army coverup of the problems of low number receivers is still believed today, and, it is the foundational basis for cover-ups later.
I should say, based on the history of all the weapons that used greased and oiled ammunition, that you would expect claims that oil or grease on ammunition causing high pressures would be viewed skeptically. But what you do find, is that “Hatcherites” are so ignorant of the design and history of firearms, that they are easily manipulated into thinking that F = MA and F ≠ MA. Well of course, F = MA all the way down to the sub atomic level.
Now as for the current cover up, expressed by Foghorn in his piece, the Army was conducting a first article test of a SAWS and its ammunition at 160 degrees °F and experienced over pressure conditions. They did experience overpressure conditions, blown case heads, etc. The Army Ordnance Corp blamed all the problems on oil. You can find a presentation on this, it is titled:
Lubrication’s Contribution to Cartridge Case Failure
www.dtic.mil/ndia/2011ballistics/11826.pdf
During a U.S. Army test, 5.56mm NATO case ruptures were experienced when firing the M249 in the hot, 160 deg °F (conditioned) environment.
M249 normally creates more case deformation than M16/M4
Hot, 160 degree (Higher Pressures, different mechanical fits than at ambient temperatures)
Low round count barrels
Weapon was recently cleaned and lubricated
Failures always occurred within the first 10 rounds of the ammunition belts
Case bulging frequently observed in rounds preceding ruptured rounds on the belt
Noticeably shorter cartridge shoulder neck length in ruptured cases
Failures of this type are not occurring when firing the same ammunition from the M16/M4
The main question, the primary question of this, is “
why are they testing ground equipment in an operational configuration at 160 °F?” . One of the first issues I am going to put out there is that the tests the Army conducted on the SAWS and its ammunition exceed operational environmental requirements given in AR 70-38 and Mil Std 810. I would like to know why the Aberdeen testers were testing outside of Army requirements. You have to read the presentation carefully before this becomes obvious, but the Army heated both the weapon and its ammunition to 160 °F and fired the SAWS fully automatic at that temperature. This operational testing at this high temperature is fundamental to my contention that the high pressures that resulted from firing ammunition and weapons at 160 °F are the primary reason for their weapon malfunctions. I would be interested to hear from an Army Acquisition person for their reasons why the Army heated both the machine gun and ammunition to 160 °F and operationally tested the two at 160 °F?.
Chirp, chirp, chirp.
It used to be that ground equipment met an -40 F to 125 °F operational temperature environment. That operation temperature range for ground based equipment goes back decades, and it worked extremely well.
I examined Mil Std 810 G for the current high temperature test requirements. Table C-I.
Summary of climatic conditions and daily cycles of temperature, solar radiation, and relative humidity shows the highest operational temperatures expected of a weapon system in a hot/dry climate to be 120 °F. These numbers change over the decades, someone bumps it up to 125 °F, another bumps them down to 120 °F. The highest storage temperatures are 160 °F, at which the weapon system is either stored, in transit, but not being used. I would consider shooting a machine gun to be an operational event, not a storage event.
Anyone who thinks humans can function in a 160 °F environment is woefully ignorant of the limits of human survival. There are very good reasons why ground equipment operational limits are 125 °F, not 160 °F. And, I challenge anyone, to run around in MOP IV battle gear, in 125 °F and see how far they can run with a full equipment load, before dying of heat stroke!.
A storage limit of 160 °F is reasonable, given that ISO shelters get very hot. Weapons and their ammunition have to survive transportation. But, the Army was testing its SAWS and its ammunition at maximum storage temperature conditions well above their own operational requirements. Ammunition has to meet a 125 °F operational requirement, and a 160° F storage requirement. But the gun, and the ammunition are not to be fired at 160°F, any weapon or ammunition heated to 160 °F has to be cooled down to 125 °F because the high temperature range is the safe storage requirement. Does anyone want ammunition self igniting at 160° F? Incidentally, my water heater has a warning label that 150 °F water will cause scalding. Who the heck is going to be handling 150 °F ammunition and a 150 °F weapon?
What is interesting is that the Army seems not know that heating cartridges raised pressures. They sure as heck did not know that heating the 5.56 cartridge to 160 °F dramatically raised pressures.
They also did not examine their specifications.
MIL-C-9963F MILITARY SPECIFICATION CARTRIDGE, 5.56MM, BALL, M193 15 October 1976
3.7 Chamber pressure.
3.7.1 Measurement by copper-crush cylinder.-The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 52,000 pounds per square inch (PSI). The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 58,000 PSI.
3.7.2 Measurement by piezoelectric transducer.-The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 55,000 PSI. The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 61,000 PSI.
3.8 port pressure.
3.8.1 Measurement by copper-crush cylinder. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 15,000 PSI ± 2000 PSI,
3.8.2 Measurement by piezoelectric transducer. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 14,400 PSI ± 2000 PSI.
3.9 Temperature stability.-When the sample cartridges are subjected to the following storage conditions, the average velocity shall not decrease by more than 250 ft/sec and the average chamber pressure by either method used in 3.7 shall not increase by more than 5000 PSI. the average port pressure by either method used in 3.8 shall neither Also , increase nor decrease by more than 2000 PSI with respect to the average velocity, chamber pressure and port pressure of the sample cartridges of the same lot, conditioned at 70° ± 2°F for a minimum of twenty minutes. Any increases in velocity and decreases in chamber pressure of the sample cartridges under these temperature conditions are acceptable.
3.9 (Cont’d) Stored at 125° ± 2°F for not less than one hour and fired at that temperature. Stored at -65° ± 5°F for not less than one hour and fired at that temperature.
MILITARY SPECIFICATION
CARTRIDGE 5.56MM, BALL, M855 MIL-C-63989A October 1984
3.7 Chamber pressure. The average chamber pressure of the sample cartridges, conditioned at 70±2°F shall not exceed 55,000 psi. Neither the chamber pressure of an individual sample test cartridge or the average chamber pressure plus three standard deviations of chamber pressure shall exceed 61,000 psi.
3.8 Port pressure. The mean port pressure minus three standard deviations shall not be less than 13,000 psi for sample cartridges conditioned to 70° ±2°F.
3.10 Temperature stability. The action time, pressure and velocity of sample cartridges conditioned and fired at the temperature extreme specified below shall be in accordance with the following requirements.
a. Conditioned at 125° + 2°F for not less than one hour and fired at that temperature.
b. Conditioned at -65° + 2°F for not less than one hour and fired at that temperature.
3.10.2 Chamber pressure. The average chamber pressure shall not vary from the average chamber pressure of the sample test cartridges conditioned to 70± 2°F by more than 5,000 psi Any decrease in chamber pressure is acceptable.
3.10.3 Port pressure. The average port pressure shall not vary by more than 2,000 psi from the average port pressure of the sample cartridges of the same lot conditioned at 70 + 2°F, but not to be less than 12,000 psi
3.12 Function and casualty. The cartridges shall function without casualty at ambient temperature and under the temperature conditions specified below in both the M249 machine gun and M16A2 rifle and
a. Conditioned at 125° ±2°F for not less than one hour and fired at that temperature
b. Conditioned at -65° ±2°F for not less than one hours and fired at that temperature.
]
MIL-C-70460A
CARTRIDGE, 5.56mm, BALL, (HEAVY BULLET) REFERENCE 1984
1984 version3.7 Chamber pressure. The average chamber pressure of the sample cartridges, conditioned at 70 ± 2 ºF shall not exceed 55,000 psi. Neither the chamber pressure of an individual sample test cartridge or the average chamber pressure plus three standard deviations of chamber pressure shall exceed 61,000 psi. The standard deviation shall not exceed 1900 psi.
3.7 Chamber pressure. The average chamber pressure of the sample cartridges, conditioned at 70 degrees plus or minus 2 degrees F, shall not exceed 58,700 psi. Neither the chamber pressure of an individual sample test cartridge nor the average chamber pressure plus three standard deviations of chamber pressure shall exceed 64,700 psi.
3.8 Port pressure. The mean port pressure minus three standard deviations shall not be less than 15,600 psi for sample cartridges conditioned at 70 degrees plus or minus 2 degrees F.
MIL-C-70460 CARTRIDGE, 5.56mm, BALL, (HEAVY BULLET)
1995 Changes: Delete in its entirety and substitute the following:
3.7 Chamber pressure
The average chamber pressure of the sample cartridges, conditioned at 70 degrees plus or minus 2 degrees F, shall not exceed 58,700 psi. Neither the chamber pressure of an individual sample test cartridge nor the average chamber pressure plus three standard deviations of chamber pressure shall exceed 64,700 psi.
In none of the specifications on the web, is ammunition or weapons tested in an operational condition at 160 °F, and yet the Army Ordnance Department is doing that. There is no reason given, but I believe that the real reason is Army Ordnance Bureau incompetence. The more you study these guys, the more it is revealed, they don't know what they are doing.
Anyone remember the Jlens blimp? This was a look down, radar equipped blimp stationed at Aberdeen Maryland. The complete Army report has not been released, but the thing got loose, dragging its mile long mooring line and knocking out power to 30,000 people in Pennsylvania. Reports are the thing climbed to 16,000 feet, and could have taken out a commercial airplane, before it came down low enough to the earth, to be shot up by Police with shotguns. The full report will never be released, but one item of interest was that the blimp did have an automatic deflation device, one that would have activated by altitude had it been working. But, some Government worker forgot to put in the batteries!.
It looks small in the picture but it is larger than the Goodyear blimp.
For sure, they don’t know their own environmental requirements as given in AR 70-38 and Mil Std 810, they don’t know their ammunition requirements and are testing both the gun and the ammunition beyond spec. Foghorn claims there is some normal cartridge pressure at 160 °F, but there is not. The highest pressure requirement the ammunition has to meet is at 125 °F. Firing ammunition at 160 °F is firing ammunition beyond its temperature specification and the pressures can be anything. Foghorn does not understand this, but then, what about the Army Ordnance Department? We see, the Army Ordnance Department is not admitting fault, are they? If you examine the presentation, just how many of the pressure problems they encounter do they attributed to temperature, and how much to oil? I would say, about 0% to temperature and 100% to oil. I am going to claim, that if they had tested oiled ammunition at 125 °F and sprayed the weapon down with oil, at °F, both should have passed, because that is the spec, at least for the ammunition. It would have been a severe test, because it would have been at the operational limits of both the weapon and the ammunition, but they should have passed. I can’t find a SAWS spec, the presentation does not reference it, and I don’t think the Army has the spec or knows who has the spec. If they Army knew what the SAWS specification and requirements were, those numbers should have been in the presentation. The lack of either shows me, they lost the spec. They don't know what they have.
But, blaming oil got the monkey off their back, right? Everyone believes that oil or grease dangerously raises pressures, right? Everyone has believed this for over 100 years, all the way back to the low number M1903 Springfields. All you have to do, is blame oil and the public accepts it. This is a great “get out of jail” card. Hillary should have blamed her email problems on oil, the public would have accepted it. She might be President today. Just blame oil.