Polishing or Not - Chambers?

[Rapier]

I build rifles.

The information in the article is interesting but very unscientific. The information also does not correspond to brass in a firearm's chamber unless you are talking about simple insertion and extraction without firing. Any roughness in a chamber will be found by a fired case and the ability to find that rough area is only enhanced by the increase in pressure. If you increase the viscosity of the lubricant, i.e., use case lube, it does prevent the case from gripping the walls and will allow the case to fully fire form and is a process used for years by wildcatters.

Perhaps had the fellow used a press, hydrolic jack and a gage to exert X pressure on his metals his experiment might have come closer to reality. But, the base of a cartridge is not as pliable as the walls and 50-65K pressure would be, as noted, difficult to duplicate in this experiment.

Get just the slightest amount of rust in a chamber and you will learn quickly about polished or non polished chambers.
Best,
Ed