Cleaning Cartridge Brass with Stainless Media — Practical Guide

This article originally appeared in Sinclair International’s Blog, The Reloading Press.
In the August 2012 Reloading Press, Bill Gravatt, President of Sinclair International, shared his experience using the Thumler’s Tumbler and stainless steel pin media to clean some .308 brass just before the National Matches. He discovered that combo is really great for cleaning brass.

This month, I want to share the results of a test I performed with stainless steel pin media, and give you some tips on how to best use this media to get cases as clean as you can. I’ve been using tumblers of some sort for more than 30 years. I got started with a sealed rotary tumber that my father and I made out of an old rock polisher we hooked up to a washing machine motor. While not as nice as a new Thumler’s Tumbler, the one-gallon capacity on that old tumbler means it’s still good for cleaning brass.

The Brass: Good, Bad and Downright Ugly
To really test the stainless steel media’s cleaning power, I mixed three kinds of pistol brass that offered different challenges. First was some very old Amron headstamped .357 Magnum brass. The late Ken Lomont of Lomont Precision Bullets gave me the Amron brass as partial payment back when I was still in high school and working for him. I’ve been shooting it for years, so it’s obviously very durable. But it’s also very hard to clean, which made it great for the test.

I threw in some once-fired nickel-plated .357 SIG brass from Federal that had a lot of soot inside. I wanted to see just how well the stainless steel media could handle really grimy jobs. Finally, I added in the worst brass — some very corroded 9mm range pick-up brass with spots of verdigris all over them and dirt down inside them. They were terrible, which made them perfect for the test.

Case Prep For Cleaning
Before I ran the cases through the tumbler, I knocked out all of the fired primers so that the stainless steel media would be able to get into the primer pockets and run through the flash holes. The media that we have at Sinclair is only .040″ in diameter, so it will easily go through the .080″ diameter flash hole on most domestic-produced brass, as well as the smaller .060″ flash holes found on some other cases. Once I knocked out the primers, I poured the brass and the media into the tumbler drum together.

Mixing The Solution
Then I mixed up the cleaning solution. I poured ¾ of a gallon of water into the unit, and then put in four tablespoons of Dawn dishwashing detergent. I also added one teaspoon of lemon juice to keep the brass from spotting when it dried.

With everything ready, I sealed up the drum and started the unit and let it run for three or four hours. When I opened the drum, I could tell the media had done a very good job of removing all of the crud from the brass. The water was black, as you would expect from all the carbon inside the cases. After pouring off the solution, I separated the brass from the stainless media and rinsed it off. It took three rinses in clear water to make sure the brass was free of all the carbon the media scrubbed off.

Then I rinsed the media, too. Rinsing the media is important: if you don’t do it, the media will be dirty when you use it next time. The media is easier to rinse while it’s still damp, and it cleans easily with clear water. As you can see, the brass cleaned up very well and showed no evidence of water spotting because of the lemon juice. The range pick-up brass came out fully usable, showing no signs of corrosion. The nickel brass looked as if it were brand new and unfired. The Amron cases looked the best that I can ever remember seeing them. Some of them still had a light amount of carbon just behind the case mouth, but a quick twist with 0000 steel wool took care of this easily during inspection of these cases before loading. All of the primer pockets were clean and clear of carbon. Impressive!

Based on what I have seen, I will definitely use stainless steel media a whole lot in the future, even though I will still keep some of the treated organic media around for when I want a very bright shine on the brass. Several of the other Sinclair International Reloading Techs plan on trying the stainless media as well, so they might come up with some other tips for you in the future.

As always, if you have questions, please do not hesitate to call on any of us on the Sinclair Tech staff to assist you.

Bob Blaine, Sinclair International Tech
NRA Certified Reloading Instructor and RSO

TECH TIPS — Avoiding Problems with Stainless Media

Do Not Use Stainless Media Dry — I have had customers call and ask if stainless steel media can be used dry. The answer is that you will not like the results. Everything will go to the media, but it will still leave the brass dirty. If you use stainless steel media dry, you have to run it through a cleaning solution to clean the media. Then, it’s good to go again.

Do NOT Use Stainless Media in a Vibratory Tumbler — When using stainless media, you need a rotary-style, liquid-containing tumbler. You want to use stainless steel media ONLY in a rotary tumbler. Do not use stainless steel media in a vibratory type cleaner.