To be clear, I'm not saying don't lube or clean the G3 design, absolutely do, no sense in letting a rifle rust, just a lot of incorrect info gets parroted around about these rifles emphasizing the flutes need frequent cleaning and special lubes being required. Being somewhat of a skeptic, I tested these things for myself, and found them patently false.
I don't know what tests you conducted. I am going to claim that whatever you did, or however you neglected your roller bolt, if it functioned, what that shows is just how robust and what a good design the rifle mechanism. Vorgrimler's team did an outstanding job in making an affordable, simple, easy to maintain, easy to manufacture, and reliable weapon. People take things like this for granted but it takes a lot of genius and effort to design a simple, robust, and cheap mechanism.
The shooting community has the memory of smoke. Something consistent with a community in which the leader's primary function (inprint Gunwriters) is to shill for the firearms industry. The community has forgotten, because its leaders are quite ignorant of, firearm history and firearm function. But there was a time before chamber flutes, when high powered delayed blow backs used greased cartridges, waxed cartridges, oilers, to lubricate the cartridges before they were fired. .
The purpose was, as Chinn states:
Untold numbers of shooters have walked, will walk, will see, machine guns like this Japanese Nambu and not understand that the tank above the chamber is an oil tank. Nor would they understand the function. This weapon used an oiler.
The man who ran the Army Ordnance Bureau knew and understood the need for chamber lubrication in high powered delayed blowback mechanisms:
Army Ordnance Magazine, March-April 1933
Automatic Firearms, Mechanical Principles used in the various types, by J. S. Hatcher. Chief Smalls Arms Division Washington DC.
Retarded Blow-back Mechanism………………………..
There is one queer thing, however, that is common to almost all blow-back and retarded blow-back guns, and that is that there is a tendency to rupture the cartridges unless they are lubricated. This is because the moment the explosion occurs the thin front end of the cartridge case swells up from the internal pressure and tightly grips the walls of the chamber. Cartridge cases are made with a strong solid brass head a thick wall near the rear end, but the wall tapers in thickness until the front end is quiet thin so that it will expand under pressure of the explosion and seal the chamber against the escape of gas to the rear. When the gun is fired the thin front section expands as intended and tightly grips the walls of the chamber, while the thick rear portion does not expand enough to produce serious friction. The same pressure that operates to expand the walls of the case laterally, also pushes back with the force of fifty thousand pounds to the square inch on the head of the cartridge, and the whole cartridge being made of elastic brass stretches to the rear and , in effect, give the breech block a sharp blow with starts it backward. The front end of the cartridge being tightly held by the friction against the walls of the chamber, and the rear end being free to move back in this manner under the internal pressure, either one of two things will happen. In the first case, the breech block and the head of the cartridge may continue to move back, tearing the cartridge in two and leaving the front end tightly stuck in the chamber; or, if the breech block is sufficiently retarded so that it does not allow a very violent backward motion, the result may simply be that the breech block moves back a short distance and the jerk of the extractor on the cartridge case stops it, and the gun will not operate.
However this difficultly can be overcome entirely by lubricating the cartridges in some way. In the Schwarzlose machine gun there is a little pump installed in the mechanism which squirts a single drop of oil into the chamber each time the breech block goes back. In the Thompson Auto-rifle there are oil-soaked pads in the magazine which contains the cartridges. In the Pedersen semiautomatic rifle the lubrication is taken care of by coating the cartridges with a light film of wax.
Blish Principle….There is no doubt that this mechanism can be made to operate as described, provided the cartridge are lubricated, …. That this type of mechanism actually opens while there is still considerable pressure in the cartridge case is evident from the fact that the gun does not operate satisfactorily unless the cartridges are lubricated.
Thompson Sub-Machine Gun: … Owing to the low pressure involved in the pistol cartridge, it is not necessary to lubricate the case.
“Blow-Forward” Mechanism: We have seen above (blowback mechanism)
that some method must be provided to hold the breech block against the barrel when the gun is fired, because otherwise the pressure of the powder gas pushing back on the cartridge case would drive the breech block back away from the barrel and let the cartridge out while the explosion was going on. With the blow-back gun the breech block is allowed to move in this manner, but is made heavy enough so that the movement does not occur too quickly.
Instead of allowing the breech block to move back, it would be quite possible to attach the stock and al the frame-work of the gun firmly to the breech block and then allow the barrel to move forward when the gun is fired instead of allowing the breech block to move back. Several automatic pistols, notably the Schwarzlose, have been constructed on this principle.
In 1917 an inventor appeared at Springfield Armory with a machine gun made to fire the Krag army cartridge, having the framework of the gun solidly fixed and the barrel loosely mounted so that it could move forward against the action of a spring when the gun was fired. This gun operated, but it was necessary to grease the cartridge case to prevent the front part of the case, expanded by the pressure, from sticking to the barrel as it moved forward.
One trouble with this system is that it greatly accentuates the recoil. The normal tendency of the explosion in the cartridge case is to push the bullet in one direction and the cartridge and breech block in the other. When there is no provision for locking the breech block to the barrel but instead it is attached to the framework and stock of the gun, and the barrel left loose, it is obvious that the explosion drives not only the breech block but the stock to which it is attached back against the shooter’s shoulder with a considerable amount of violence.
This inventor had besides his machine gun, a semiautomatic shoulder rifle built on this principle, though the mechanism was only crudely worked out. He demonstrated this gun by firing a number of shots with it and then allowed the Armory officials to fire it. I fired one or two shots with it and the kick was so terrific that I felt as though a mule had landed on of his hind feet on my shoulder. I seemed to be kicked back two or three feet from where I was standing and tears actually ran out of my eyes from the blow, which marvel as to how the inventor, who was a frail, pathetic looking man, managed to shoot it without any signs of discomfort. After showing his model he returned to a nearby factory to complete the mechanism but a few days later we were distressed to learn that he had taken his new gun and deliberately blown his head off with it. Probably the kick was too much for him after all.
From what I read, the Soviets used chamber flutes. But once chamber flutes became a proven technology, greased ammunition, oilers, pretty much went on the ash heap of history. None of the inprint authorities today would have any operational memory of a weapon that used oilers or greased ammunition, even though, video gamers and historians, have retained the memory.
The Oerlikon 20mm was the most common auto cannon during WW2 and the WW2 versions used pre greased ammunition
Naval Legends: Oerlikon
it is mentioned at 4:15 in the video that the cartridges are pre greased.
Chamber flutes use gas lubrication to break the friction between case and chamber.
Increasing friction between the case and chamber is the surest way to cause a failure to extract. The Germans who issued G3's to their troops understood the peculiarities of their roller bolts and issued ammunition used clean burning powders and did not tar bullet sealants, such as the tar found on US 7.62 ammunition. I talked to PTR after I purchased my weapon and the representative their explained that tar sealant will condense and gum up the chamber flutes. If the flutes are clogged, then reliable operation of the weapon is compromised. PTR used to have a long list of ammunition they don't recommend using in their rifles. This is what they used to say:
Ammunition:
PTR 91 INC, Rifles are newly manufactured and are made to exacting standards and close tolerances. These rifles are made to function with commercial factory.308 cal ammunition. We do not recommend the use of reloads or of surplus ammunition. If surplus ammunition is used beware that this ammunition varies from manufacturer to manufacture, lot to lot, year to year, components used and processes in manufacturing. All this ammunition is not made to exact specification. We have found that some of this ammunition has caused problems in our rifles because they use a tar like sealant in their water proofing. When this ammunition is used in our rifles the sealant melts and coats the chamber. This causes failures to extract and to chamber. Afterwards any ammunition that is used will have the same problem if the chamber and the bore are not cleaned thoroughly. We have found surplus ammunition from the following countries/manufactures that have caused this problem in our rifles. That we know of at this time.
I can't find this on the PTR site anymore, maybe enough surplus ammunition has been blown downrange that this issue has gone away. But, keeping the chamber and its flutes clean is fundamental to reliable feed and extraction. This is not a myth.
Incidentally there are still high powered retarded/delayed blowbacks on the market which use lubricated cases. I believe industry anticipated stupid and ignorant reactions from many about greased or oiled cartridges, so their marketing bureaus told the gunwriters to call the special ammunition for these weapons "polymer" coated. Never have a read a description why these rounds need to be "polymer coated", but it is because the coating is a lubrication, there to break the friction between case and chamber. Without the lubricant coating the case will be torn in half. Reloaders who don't know that, damaged the coating in reloading these cases, and I read a report of a serious injury due to a separated case. It is very likely the gunwriters are simply using the description they were told to use, also likely they don't understand that the "polymer" functions as a lubricant. And I suspect neither the authors and their readers know that grease, oil, wax, teflon, are all polymers!
In so far as weapon neglect, clean to your psychological level of happiness. I am amazed by the number of Cops whom I have heard about, who neglect their weapons. A shooting bud of mine is a retired State Trooper. He told me of visiting one of his men, and inspecting the shotgun stored in the cruiser. He pulled it out, tried to rack the slide, and found the weapon was rusted shut! I just don't understand the attitude of people like that, and have met many. I think everyone has a friend who drives around with no spare, or a flat spare tire, and no bumper jack. I am not one of those types, I think what can go wrong, will go wrong.
