For those who have had unexplained issue with the brass they clean in a wet Stainless Steel pin tumbling set up I have the answer!
Been using my Frankford Arsenal wet tumbler for most of a year now and have been very happy with it, learned years ago with the dry type that you can't mix different caliber case's while cleaning, ever have a 22 case stuck in a 32 auto case stuck in a 9mm case stuck in a 40 case stuck in a 45 auto case??
I have, before cell phones or I'd have a picture, LOL!
Well I recently had a similar issue with the wet pin system tumbler but instead of a case jamming issue it was a bunch of brass 45 auto case which came out of the cleaner a dull grey color rather than the bright brass color I usually get.
Cause? Your gonna like this: a handful of Nickeled case's in a batch of range pick up that I was cleaning for reloading!
Never had the issue before because I dislike Nickel case's, and haven't cleaned any 38 or 357 case's with the wet system yet so had no other experience with that problem.
I believe the SS pins rub some of the Nickel finish off and spread it around to the brass finish while tumbling, currently I broke out an old dry walnut type vibrating tumble and am polishing the "tarnished" case's in that.
First batch came out perfect so it is a contact type tarnish effect and can be cleaned easily with the dry type media, interesting in that I found the inside of the case's perfectly clean and shiny but the outside tarnished badly.
From now on I will inspect and separate nickel case's and clean them separately from yellow brass, just wanted to post my findings as I have seen other posts where the poster was as confused as I was about the sudden loss of bright shiny brass!!
Today's other project will be to clean a sample of 9mm brass in the wet SS pin set up and see if the pins are contaminated !!
with luck their not but only one way to find out.
Hope this helps others avoid the same problem.
HM