http://www.odcmp.org/1101/can.pdf
It seems that whenever a discussion of leaving lubrication on cases comes up, someone has to pull out the section from Hatcher’s Notebook on the 1921 Tin Can ammo
In 1921 the military introduced tin coated bullets for national match ammo at Camp Perry. Tin from the jackets flowed into the brass of the case necks, effectively welding the bullet to the case neck. This created a bore obstruction.Receivers cracked, bolts cracked, it was scandalous. At the time, most of the rifles on the line would have been the single heat treat 03’s, many of which had brittle receivers and had very little margin of strength anyway.
The military, following the second law of Government : “Minimize Scandal”, decided to find someway to blame the damaged rifles on the civilians.
Civilians had been dipping their bullets in grease to reduce copper nickel fouling. They had been doing it for years, maybe a decade. The military seized on this, ran rigged tests, and “proved” that greased bullets were the problem, not the bore obstruction they created.
I think the millions of moly greased bullets fired down barrels have proved their tests were bogus.
Guns are designed ignoring case friction. Just imagine, a designer designs a firearm assuming the case takes 50% of the friction. Then someone sneezes on a round, the friction goes to 10%, and the lugs are sheared on the firearm. Making any sort of assumption that a case will maintain any level of friction is a stupid assumption. Since the designer cannot prevent users from blowing snot on cases, or leaving bore cleaner in the chamber, ignoring case friction is a far more prudent way to design the locking mechanism.
In fact, you will find that a frictionless case would be the designers “ideal case”. Breech friction requires heavier extractors, more extraction force, requiring bigger buffers, etc. It would be so nice to have a case that just fell out without requiring primary extraction.
In the end, breech friction will defeat all semiautomatic mechanisms. You can take that to the bank.
Recently I was having problems sizing 9mm cases on my Dillion 550B. I have a lot of range pickup brass. Some of which was fired in chambers so large, that lots of cases were getting stuck in the carbide die. Of those cases the rim was being pulled off. I got tired of taking the die apart and reassembling the thing. So I tumbled the rest of that 9mm brass with a light coating of RCBS water soluble case lube.
Sizing became a breeze. I decided not to remove the lube and went out and shot the stuff. Guess what, of the several hundred cases I fired, I had no problems in my Walther P5. No funnies, no issues, no nothing.
I talked this over with an engineer at the range and found that he was leaving the lube on his pistol cases. He made several points that might be true. First of all, lubed cases are easier to extract and thus are easier on the pistol. Since lubricant is wetting whatever residue is in the chamber , extracted rounds are removing chamber residue on extraction. This should have the effect of keeping the chamber cleaner.
I believe that some ammo companies coat loaded rounds with a hard polymer wax. To keep the rounds shiney on the shelf. Just as with the Pederson rounds, this coating is so thin you cannot detect it. And a polymer wax will act as a lubricant under heat.
If you are loading over pressure ammunition than lubricating the cases will increase the bolt thrust over an non-lubricated case. The solution to this is not to load overpressure ammunition. Ever.
