I've noticed that many students of US military rifle lore think of the difficulties encountered with the 1921 "tin can" match ammo whenever lubricated cases are discussed. The actual problem with the 1921 ammo was not case lubricant but bullet lubricant inappropriately applied. To quote Hatcher, "If the bullet had been dipped in grease, this generally meant that the neck of the cartridge was greasy too. The space between the neck of the case and the neck of the chamber was filled with an incompressible substance, and the first moderate rise in pressure found it impossible to expand the neck and release the bullet. Thus the powder was strongly confined right at the beginning of its ignition, and accordingly the pressure rose disastrously." (Hatcher's Notebook, p 341).

As described by Hatcher, this problem was quite distinct from the added breech thrust occurring when the case body is lightly lubed. Although careless application of excessive case body lube could certainly have the same effect, such a result is easily avoided by applying only a very thin film. I like castor oil for this because it's cheap, super-slick, easily applied, and viscous enough not to run where it isn't wanted. I've never tried the paste-wax approach, but reports from others indicate it's effective (and doesn't collect grit).
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