This is going to torque the sensitivities of those who put Hatcher on a pedestal, and live with a romantic view of Springfield Armory, the Army, and the Army Ordnance Bureau, but I am going to call Hatcherism the belief that
Cartridges should never be greased or oiled, and the bullets should never be greased. Grease on the cartridge or in the chamber creates excessive and hazardous pressure. It operates to reduce the size of the chamber and thus increases the density of loading and the pressure.
These are Townsend Whelen’s words; General Hatcher did not come up with this belief system , it is in fact based on a data set created by then Major Townsend Whelen, but Hatcher is the “St Paul” of this religion. Without him this would have faded away and at best, would have been a historical curiosity.
Now the cartridge is the weakest link in the whole system. But if you really think about it, Hatcherites believe the case is strong, and the action is weak. This is, in a word: nuts. The case is a thin brass tube/pressure vessel. The idea that the thin brass sidewalls are there to take load off a 1/2" thick steel structure, is, nuts.
While, Hatcherites are rightly concerned about increasing bolt thrust, but their belief system is screwed up
The case is a gas seal, the action is there to protect the case from stretching, from rupturing. You rupture the cartridge case , gas will rush out into the mechanism, and the firearm is not designed to take the gas load, and, particularly for older mechanisms, will blow up in fragments. I have not studied the load limits of cartridges, but it is obvious brass is weaker than steel.
One of the common fallacies I see with Hatcherism and Hatcherites, is that Hatcherites don’t think in terms of load limits. To a Hatcherite, loads are either increasing, or decreasing, doubling, halving, but the concept of a load limit is incomprehensible to a Hatcherite. A Hatcherite can drive down the street, trees on the left, buildings on the right, and to a Hatcherite, all have just grown there, endowed by the Supreme Deity, with all the structure necessary to stand, and the why’s and wherefores are unknowable. If you believe in intelligent design, God has not published his book on tree mechanics. However, all man made structures, designed since, let’s say, the Industrial Revolution, by certified engineers, those building were designed to a load, and a lifecycle. Exceed those design loads, and the building will in time collapse.
It is obvious that the Rana Plaza disaster was the product of the fuzzy, wuzzy, timey, wimey, thinking by Hatcherites. Read about it before Wikispaces goes away:
https://failures.wikispaces.com/Rana+Plaza+Building+Collapse
In the thread,
Machine gun Oiler ?https://www.thehighroad.org/index.php?threads/machine-gun-oiler.838074/
Lysanderxii makes the following comments:
But, let’s break it down:
If you reduce the friction between two objects trying to slide past each other, the retarding force goes down. That ought to be a “no-brainer”. So . . . .
1) When you fire a cartridge the chamber pressure will try and force the case out the back of the chamber, but the case stays in place due the action of the locking lugs and the frictional drag between the case wall and the chamber wall.
2) The pressure in the chamber will produce an extremely high force pressing the case wall outward to the inside of the chamber.
3) The retarding frictional drag will be the coefficient of sliding friction (μ) times the force expanding the case minus the elastic tendencies of the case.
4) The load on the locking lugs is the chamber pressure times the area of the inside back of the case, minus the retarding frictional drag.
5) Lubrication will reduce the coefficient of friction.
Therefore, in should be obvious to the most unlearned in physics that a reduction in the coefficient friction, i.e., lubricating either the chamber or the cartridge, will increase the load on the locking system.
These are all good points, and true, the real question is, how do you design a locking mechanism, what loads does the designer assume? I'll tell you how I would do it, I would assume the maximum load to be the maximum pressure of the cartridge times the diameter of the case at maximum case head separation. For a rimless case, pretty much that is maximum cartridge pressure times the OD of the case. That will give the maximum load on the bolt face. As long as you don't exceed the maximum pressures of the cartridge, you are not going to over stress anything. Ever noticed those SAAMI maximum pressures in loading manuals? There is a relation ship between and the structural integrity of your rifles. Its called load.
The next question is, and this is the most important question to those who are concerned about bolt thrust, and desiring the case carry load, is just by how much do you weaken the locking mechanism, assuming the case does carry load? I would like to know this, and I will offer a simple way to think of this, if the question is too confusing for you. Lets say the 100 % load, that is the maximum load, is pressure maximum times the OD of the case. So by how much, in percentage do you weaken the locking mechanism, assuming the case carries load. Do you weaken the locking mechanism by 10%, 20%, 30%, 40%, 50%, or even more? And how do you maintain that in the field? After all, after weakening your locking mechanism by a fixed amount, won't your action break if someone fires a neck sized case in the action, or leaves oil in the chamber, or chambers oily rounds? Chart 7 of
Lubrication’s Contribution to Cartridge Case Failure, more or less acknowledges the problem of fixing the weakening percentage in this bullet:
- Coefficient of Friction between case and chamber. Highly variable
Well of course, it would be the poor engineer who designs any structure to fail, at less than the maximum load. But, this is one of the fallacies of Hatcherism. I am going to say, it is absolutely impossible to design a locking mechanism following the dictates of Hatcherism, because Hatcherism is a physically incoherent philosophy. And I am going to say, I have never had a Hatcherite provide the weakness percentage. What I believe is, the whole discussion is either incomprehensible, or, because it so conflicts with their strongly held belief system, they ignore it. Lysanderxiii correctly describes what happens when you reduce case friction, it increases the load on the locking mechanism, and yet, he does not take the next step, assume zero case friction, and build a locking mechanism to withstand that load. It is obvious that Lysanderxiii is an Army Ordnance Engineer, lets say he represents the Army in this, reflects Army attitudes about this, and yet, he gets up to this line, and cannot cross it.
To me, the failure analysis in this Army study, is greatly lacking:
Lubrication’s Contribution to Cartridge Case Failure page 60 on this 80 megabite file:
http://www.dtic.mil/dtic/tr/fulltext/u2/1006032.pdf
This study is the basis for a discussion initiated in this thread:
Machine gun Oiler https://www.thehighroad.org/index.php?threads/machine-gun-oiler.838074/ Machine Gun Oiler was terminated early by a Moderator for unfathomable reasons. .
One of the first things you document in a failure analysis are the design limits of the items under investigation. For an electrical engineer, I am certain that such characteristics as Voltage, Amperage, would be top of the page. It would be easy to see that if the maximum voltage the device was rated for was, 120 V, and someone hooked up 220 Volts, it would be easy to understand why the electrical device failed. For mechanical structures the maximum load on the structure, which would be pounds force. As an infantile example, if the maximum weight the bridge was designed to carry was 20 tons, and the load at the time of collapse was 40 tons, it would be immediately obvious why the bridge failed. . You can look at the Rana Plaza short study referenced above, and it becomes obvious that the original design of the building was inadequate to support the additional weight added in later modifications.
So, where in the presentation to
Lubrication’s Contribution to Cartridge Case Failure are the maximum design loads of the M249? What load, in pounds force , did the designer use in designing the bolt structure? Well for one thing, the Army did not design this weapon, they bought it as a non developmental item, which means it was fully designed by the Contractor and they are not going to give either the technical data package, nor the design information to the Government unless the Government pays for it. I am 100% certain the Government did not buy the Designer’s Notebook. But, they could have inferred the maximum design loads on the bolt face by reverse engineering the bolt face, assumed some safety factors, but they did not do that either. The Government did not also state what the maximum operating temperatures the weapons was supposed to operate at. While they knew (or should have known) that the maximum operating temperature of their cartridges is 125 °F, but this is not mentioned in the study, but if you examine the study, they are shooting both the cartridge and the gun at 160 °F. To determine the maximum operating temperatures of the cartridge, you have to find the cartridge specifications and read. I posted a number of the spec limits in the thread
Machine gun Oiler https://www.thehighroad.org/index.php?threads/machine-gun-oiler.838074/ For chart 18 of the study
Lubrication’s Contribution to Cartridge Case Failure , the out of tolerance pressures they are using to calculate bolt load, are 72 ksi, temperature at 160° F. Proof pressure cartridges are 70,000 psia, you can look this up, so why do they consider operation at 72,000 psia normal?
It ought to be obvious that the Government is running both the cartridge and the gun beyond spec, but it is curious to read they are blaming oil as the problem. Oil is the least of their problems, but I will acknowledge that lubricating a case will increase bolt thrust. It also eases extraction. A simple question, do you want your cases to extract, or not? A simplistic summary of the Government’s study
Lubrication’s Contribution to Cartridge Case Failure is that the Government fired +P+ ammunition in a mechanism not designed to those pressures, and blamed oil for all their problems. I have theories why this answer was provided, but I can’t prove them.
Lubrication’s Contribution to Cartridge Case Failure should have also explained why, those early mechanisms that used greased and oiled cartridges function perfectly well, but lubricated cases in the M249 did not. If lube is bad, if increased bolt thrust is bad, why were trillions of rounds fired out of those things, why were they fielded? I truly think the Army does not know their firearms history, is unaware of these things, even though the number of fielded weapon systems that used oilers, to oil the ammunition is vast.
As to the historical use of oilers, I went to The Machine Gun History, Evolution, and Development of Manual, Automatic, and Airborne Repeating Weapons by George M. Chinn Lieutenant Colonel,
USMC VOLUME I OF FIVE VOLUMES
I was surprised to find that case lubricant prevented case head separation in weapons with excessive headspace. This is not a practice I advocate, because I would be concerned with action peening, but evidentially billions of lubricated rounds were fired in mechanisms with excessive headspace.
http://ibiblio.org/hyperwar/USN/ref/MG/I/
Do notice that Major General Hatcher is mentioned on the acknowledgements.
Schwarzlose Machine Gun, 8 mm. page 231
This system is appropriately designated retarded blow-back. Due to the fact that the cartridge is extracted under relatively high gas pressure, it was found necessary to lubricate the ammunition. Schwarzlose settled this problem by installing, as an integral part of the weapon, a pump to lubricate the cases. This device pumped a squirt of oil in the chamber between each extraction and loading. The combination of the lubricated ammunition, heavy spring, large bolt assembly, and short barrel allowed the use of an unlocked action which proved quite satisfactory.
Chapter 16 Revelli Machine Gun --251--
An oil pump for automatic lubrication of each round was an integral part of the receiver.
Chapter 8 Nambu Automatic Weapons page 353
All Nambu machine guns were gas operated and air cooled with many radial fins giving more surface for cooling. The earlier models had rectangular gravity oil reservoirs so that as rounds were fed into the feed opening they engaged a spring-loaded lubricator. This action caused oil to flow through perforations onto the cartridge cases. Such lubrication was needed because manufacturing the components to such close tolerances as to permit a workable head space had not been possible at the time. The oil permitted the cartridges to slip back against the bolt until lock clearance was taken up, thereby eliminating the danger of a ruptured cartridge case
Chapter 9 Revelli Aircraft Machine Gun page 354
The Italian Air Force during World War I was so desperate for an adequate rifle-caliber machine gun of native origin that it ordered the lightening of the water-cooled 1914 model Revelli. This was accomplished by the removal of the water jacket and use of an air-cooled barrel with longitudinal ribs. It not only gave more cooling surface but also strengthened the barrel, cutting down dispersion. The rate of fire was increased by use of ammunition more thoroughly lubricated by means of a built-in oil pump.
Chapter 21 Breda Machine Gun page 416
A large oil reservoir was built into the top of the receiver, directly over the feedway. This lubricator was operated by the recoil and counterrecoil movement of the barrel and barrel extension, squirting oil with each complete cycle on the rounds then being positioned on the floor of the feedway.
Page 419
Like all Italian machine guns oil was used freely on the ammunition since head space was not adjustable on the weapon. The fixed relation between the front face of the breech-lock receiver and the gas port in the barrel made impossible rotation of the barrel in order to advance or retract the chamber for correct head space. The oiling of the ammunition was resorted to in this case in order to compensate for the above condition.
Chapter 29 Sistar Machine Gun page 465
The light machine gun, while having only a 20-shot magazine, did have a feature that the company made great effort to demonstrate on every occasion. The gunner, without rising, could pivot the swinging magazine forward from the prone position and insert in a matter of seconds a fresh supply of loaded rounds directly from the cardboard container into the feed system. By this ease and speed in loading he could keep up practically uninterrupted fire.
The weapon was recoil operated, the barrel having an open jacket that gave it support and a bearing for "floating" the recoiling parts.
A built-in oil pump on the left side of the receiver sprayed a small jet of oil on the incoming rounds as each was positioned for chambering. This device was actuated by the recoil and counter-recoil movement of the barrel extension.
Polsten Cannon page 521
One of the principal differences between the Polish-designed gun, known officially as the Polsten 20-mm Automatic Cannon Mark I, and the original Oerlikon was the built-up receiver of welded construction which had heretofore added greatly to the machining problem in mass production. The Polsten gun was also lighter in weight, but as the weapon was intended for shipboard and ground use, this did not seem of too much importance to the British. It could be fed both by clip or drum magazine, and could only be fired full automatic.
Chinn does not mention that the rounds for the Polsten Cannon were greased but this will be found in Brassey’s “Small Arms” by Allsop and Toomey. In fact, Brasseys Small Arms has a whole section starting page 70 about case lubrication.
The Machine Gun Part V
Chapter 14 Birkigt Type 404 20-mm (Hispano-Suiza) Cannon
--578--
After further comparative tests in late April 1942, it was again definitely decided by the Ordnance Department that all American-made 20-mm automatic guns continue to be made with the chambers longer by one-sixteenth inch than the British regardless of the employment of the same ammunition. This decision was final as far as American production was concerned, but in no way did it change the British representative's view on the longer chamber's performance.
Oddly enough, the question was again raised, not by the English or our many proving grounds, but by manufacturers of 20-mm ammunition. In testing their cartridges for reliability of action, they encountered a series of malfunctions known as light-struck primers that were all out of proportion for such a weapon. These were not isolated cases, the reports coming in from practically every maker of 20-mm ammunition that was engaged in function firing his products.
Since the munitions companies pointed out that the faint strikes were due to lack of impact on the primer resulting from error in the gun, and not as a result of defective materials or workmanship, it was decided to conduct another test on an extensive scale at Aberdeen. Ninety of the 20-mm guns, M1 and AN-M2, selected from every facility producing them, were expended in this test with all types of ammunition, both from accepted and rejected lots.
A complete record was made of every malfunction during the entire test and the probable causes of the trouble. The engineers in charge of the project in the early stages of this test recommended that two modifications should be made to overcome the serious malfunctions:
"(1) Shorten the chamber one-sixteenth inch, thus modifying it to approximately the British chamber.
"(2) Replace the extractor spring with a solid plug, thus positioning the rounds by means of the extractor. This change would include such modifications to the extractor, the bolt, and the ejector, as were deemed necessary."--588—
During war all that can be done is to install and make function as reliably as possible that which is issued. With the mounting of the 20-mm cannon in Navy, planes a series of malfunctions began that could not be properly corrected at the time because manufacture was at the peak of production. The slightest change would practically mean retooling. The most serious problem was the oversize chamber. There still remained considerable variance in dimensions between the chambers of the British and American cannon, even after the latter chamber was made one thirty-second inch shorter
Due to an outmoded agreement of long standing, everything above caliber .60 in the Army is considered artillery and the manufacture of the Hispano-Suiza cannon therefore came under this classification. In other words the production of this high-speed machine gun was done under artillery manufacturing tolerances. The resulting poor mating of parts, coupled with the inherent fault of all gas-operated weapons whereby the breech locking key in the receiver is immovable and the position of the gas port in the barrel is permanently fixed, made it impossible to adjust the relationship between barrel and breech lock to establish head space. Thus the most vital measurement in any automatic weapon was governed by chance in this instance.
An unfortunate discovery was that chamber errors in the gun could be corrected for the moment by covering the ammunition case with a heavy lubricant. If the chamber was oversize, it served as a fluid fit to make up the deficiency and, if unsafe head space existed that would result in case rupture if ammunition was fired dry, then the lubricant allowed the cartridge case to slip back at the start of pressure build up, to take up the slack between the breech lock and the breech lock key. Had this method of "quick fix" not been possible, the Navy would have long ago recognized the seriousness of the situation. In fact, this inexcusable method of correction was in use so long that it was becoming accepted as a satisfactory solution of a necessary nuisance.
Incidentally, there were a lot more mechanisms that used lubricated cases, and some still do, than what are listed in Chinn’s Machine Gun series. Some mechanisms require breaking the friction between case and chamber to function. All mechanisms, lubricated cases or not, will malfunction at some point with over pressure ammunition.
Hatcherism has been around for over a century and while it allows the Army scapegoat oil for problems they have created, it has caused behaviors that cause malfunctions. The Army is lubrophobic (pathological fear of lubricants) and for decades has warned about over lubricating, in fact telling its Soldiers to run their weapons dry. That is terrible advice if your side arm is a M16/Ar15. That weapon needs to be run wet. The guys in the video don’t know the origin of the bad advice, but they certainly show the bogosity of it all:
I don’t have the design notebooks of those who designed those early mechanisms, but I have read Col Chinn’s series on the Machine Gun. He does have the simple calculation of bolt thrust, (I forgot the page) but I do remember, he did not weaken the locking mechanism assuming the case carries load. It is worth reading the blowback section in Vol IV, available for free, here:
http://www.ibiblio.org/hyperwar/USN/ref/MG/
I do have my Brassey’s Essential Guide to Military Small Arms, by D. Allsop, anyone can get this book through interlibrary loan, because the thing is now too damn expensive to buy, at $500 for a used copy,
https://www.amazon.com/MILITARY-SMALL-ARMS-Principles-Operating/dp/1857531078/ref=sr_1_fkmr0_1?s=books&ie=UTF8&qid=1522096298&sr=1-1-fkmr0&keywords=brassey's+military+small+arms+d+allsop and you will see, design books on fire arms do not weaken the mechanism, based on the assumption that the case carries any load. I have talked to two firearm designers, one designed the locking mechanism for the Armalite 50 cal, and the other was a cannon designer. Neither of them assumed any case friction, and neither weakened his mechanism, assuming the case carried load.
Anyway, regardless of the structural strength of any action, the cartridge case is far weaker, and any designer who weakens his action, assuming the case is going to carry load, is designing products what will hurt the user.
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