Oil in the chamber is usually a good thing in a self-loading weapon. The cartridge case is a piston in a cylinder (the chamber) and is much more easily extracted if it is lubricated. Lubricating the ammunition is one of the first things to do if it starts to run poorly in a desperate situation and you cannot clean it.
Theoretically, oil on the case can penetrate the joints between the primer and the case or the bullet and the case and contaminate the primer or powder. If you are going to shoot this ammo immediately that is of no concern. A thin film of grease on the case can stay there a longer time with no danger of contaminating the propellant. So if you are concerned about a failure to extract malfunction with your defensive weapon, lightly grease or wax the cases. Contrary to conventional wisdom, this is OK to do. Really!
Dave
Boonie Packer

