Oil/Lube on Case -- Bolt Thrust Effects:
Folks, please look at the following data/calculations for a a 243 with varying degrees of "smooth/lubed" chamber
Summary Table with Estimated and Measured Coefficients of Friction
(About 2/3rds down the page)
Barring grease so thick that it forms a hydraulic lock, slightly lubed cases/chambers just aren't a problem.