Tumbling - What Media???

[DavidJayUden]

Couple of thoughts.
Avoid using anything to lubricate, wax, or preserve the finish on your brass. A very important function of brass is its ability to expand and "grip" the walls of the chamber on firing. If you lubricate the cases of a centerfire bolt action rifle and fire it, all fo the recoil goes directly into the face of the bolt and its locking lugs, sometimes making raising the bolt handle difficult, the same symptom as high pressure. In short, lubed cases are really hard on guns, probably including old Lugers.
I'm no machinist, but I suspect that a high degree of polish is not part of reaming a chamber.
As far as Brass-O being harmful to brass, that's news to me. I've been adding a few drops to media for a long time, and have never had any reason to suspect the results. In fact, I've recently had reason (new gun) to start once again start shooting up some .223 reloads, which I just realized were last reloaded by me in 1990.
But then my goal in polishing and reloading brass is for function, not looks.
dju