So, I ordered a brass tumbler plus stainless steel media for my father in early December, because the motor on his old RCBS that he got in the 80s was starting to go out. Since anything gun-related is so difficult to get these days, it took exactly two months (by the date) from Christmas to come in. But damn, son, the results are worth it.
Dat brass.
In the first picture, the left case passed through corncob media about 2-3 times. The right case (and everything behind it) passed through stainless media exactly once. These cartridges are not new, either, and as you can see by the latter shots, even the primer pockets have been cleaned. It's amazing what small steel pins, water, dish soap, and lemishine can do. (Side note: This might work on anything else that needs polishing and also happens to be relatively soft metal.)
Some Info for the Curious
None of this brass is an accepted standard (either by SAMMI or the Euro standards, CIP, I think) and is thus considered a "wildcat" round. The curious thing about wildcat cartridges is that you often have to make the brass yourself by re-necking similar calibers--there's no factory loads. We're lucky in this case, though, because the reason the headstamps show Remington's mark is from a limited production run in the late 80s/early 90s of the 7mm BR (brass only). Because competition shooters are rediscovering some of the old wildcats, 7mm BR is back in limited production as of last year. Good luck getting any, though. It's been sold out for over 2 months. Making it yourself by cutting down existing .308 brass and re-necking is time consuming and subject to ruining a certain percentage of the parent brass if not correctly done, so obtaining pre-made stuff is ideal.
Guess who's had that on order for over two months as well?
Oh, and I should point out that these were not originally designed for rifles, in spite of what the bottleneck might suggest. They're for the Remington XP-100 bolt-action pistol. Borderlands fans rejoice. The 80s is calling and it wants to tell you that those weird guns you've picked up on Pandora were already dreamed up decades ago.