Some full auto firearms require oil to be sprayed on the ammunition before using it. The Italian Breda MG is one.
It is usually dangerous to oil cartridge cases before shooting them. There is a great deal of expansion of the ctg case to the chamber walls and if the ammo is oiled, it will cause excessive bolt thrust to the rear.
The reason I am mentioning this is , a fellow brought a Savage 99 in .243 Win to me because the wood was shattered and he needed the stock replaced. As a matter of form I checked the headspace. The chamber would eat the field gauge with almost 1/8" to spare. He then told me they were having problems with extraction. They oiled the ammo and the problems stopped. What it did was cause excessive bolt thrust and it actually increased the headspace to the point that the ctg cases separated. The high pressure gas escaped into the action and shattered the buttstock. All they would have had to do was clean the chamber. A nice 99 was ruined this way.