Tuesday, May 10, 2022

Reloading: Brass Cleaning

One of the things I mentioned in my reloading overview post was starting with clean cartridge cases. The importance of using clean brass cannot be overstated.

When fired, the inside and outside of a cartridge case is covered in gunshot residue (GSR). Gunshot residue is primarily the result of incomplete combustion of smokeless powder, possibly combined with any lubricant used on the bullet or in the bore of the gun. If fired in a semiautomatic firearm, the case will also pick up grit and debris from landing on the ground. 

All of these contaminants are much more likely to damage your reloading dies by scratching their insides, and they also increase your chance of getting a case stuck. This means that your cases need to be cleaned well. Luckily for you, there are several ways to achieve this goal.

L-R: Dirty; vibratory cleaned; wet cleaned cases

The most common type of brass cleaning equipment is the traditional vibratory case cleaner, which is made up of a bowl that contains the cleaning media and the brass on top and an off balance electric motor underneath. In operation, the motor generates vibrations which propagate through the bowl, causing friction between the media and the brass, scrubbing off contaminants.
Vibratory Case Cleaner

These cleaners are sold either on their own, or as part of a kit that includes a media separator. (An even simpler media sifter is also available.) Speaking of media, there are two types available: corn cob and crushed walnut hull.
  • Corn cob media is softer and generally less expensive. While it doesn’t clean as efficiently as crushed walnut hull, it does produce shinier brass. 
    • Even though the price for corn cob media is fairly reasonable, blast media is basically the same thing and can be found for an even lower cost.
  • Crushed walnut hull media is more aggressive in cleaning, but doesn’t generate as shiny a finish. However, it is usually more expensive than corn cob. 
    • Lizard litter for reptile terrariums is generally the exact same stuff, but at a lower price.
Brass polish can be added to either type of media if shinier brass is desired.

Corn Cob (L) and Walnut (R) cleaning media

    An alternative that’s been getting more popular over the past decade or so is wet tumbling using stainless steel pins as the media. The canister is loaded with brass, water, pins, and any additional cleaner (I use a couple tablespoons of dish detergent), then put on the base unit which rolls the drum for a set amount of time agitating the contents and cleaning the brass. This can produce brass that is nearly as clean as unfired, factory-new cases.

    Wet Tumbler with Stainless Steel Pins and Magnet

    Separation of the stainless steel pins from the brass is a bit more involved than with the dry media system, and a magnet can be very helpful. The brass and pins will also require a drying stage, either by letting them sit out to air dry, or run through some form of heated drying system.

    A tumbler style brass cleaner for use with either dry or wet media can also be made at home. There are a variety of designs, such as this one; other designs use a robust electric motor (like those found on treadmills), a five gallon bucket, a gamma seal lid, and a few other components.

    Hopefully this information is interesting and useful to those of our readers who are considering getting into reloading, are new to reloading, or even those who are already experienced reloaders.

    In the meantime, keep your powder dry and your brass clean.


    1. There's also ultrasonic which produces very good results as well. Harbor Freight has a unit that is same as Lyman's - and only $85 versus $135 for the Lyman. Same unit, though.

    2. I wish I would have waited to get my Lyman ultrasonic unit. I don't use it that much, and I could a saved some money.

      The tumbling method works pretty good for me. I usually just stand the brass up on the hot water heater. It's warm enough to drive the water out like a dehumidifier rod.

      Thanks for the great writeup.

      ---Matt R.

    3. Question: How many times can you clean the same piece of brass before there is excessive wear or damage?


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