How to Prep Mil-Surp Once-Fired Brass

The U.S. Army Marksmanship Unit publishes reloading “how-to” articles on the USAMU Facebook page. One Wednesday “Handloading Hump Day” post covered preparation of once-fired 5.56x45mm brass. This article, the first in a 3-part series, has many useful tips. If you shoot a rifle chambered in .223 Rem or 5.56x45mm, this article is worth reading. And visit the USAMU Facebook page for other hand-loading tips.

This week, Handloading Hump-Day will answer a special request from several competitive shooters in Alaska. They asked about procedures for morphing once-fired GI 5.56mm brass into accurate match brass for NRA High Power Rifle use. The USAMU has used virgin Lake City (LC) 5.56 brass to win National Championships and set National Records for many years. In this 3-part series, we’ll share techniques proven to wring match-winning accuracy from combat-grade brass.

Preparing Once-Fired GI 5.56 Brass for Reloading (Part 1 of 3)
Assuming our readers will be getting brass once-fired as received from surplus dealers, the following steps can help process the low-cost raw material into reliably accurate components.

1. Clean the Brass
First, clean the brass of any dirt/mud/debris, if applicable. Depending on the brass’s condition, washing it in a soap solution followed by a thorough rinsing may help. [This step also extends the life of the tumbling media.] Approaches range from low-tech, using gallon jugs 1/2 full of water/dish soap plus brass and shaking vigorously, to more high-tech, expensive and time-consuming methods.

2. Wet-Tumbling Options (Be Sure to Dry the Brass)
When applying the final cleaning/polish, some use tumblers with liquid cleaning media and stainless steel pins for a brilliant shine inside and out, while others take the traditional vibratory tumbler/ground media approach. Degree of case shine is purely personal preference, but the key issue is simple cleanliness to avoid scratching ones’ dies.

Shown below are Lake City cases after cleaning with Stainless Media (STM). Note: STM Case cleaning was done by a third party, not the USAMU, which does not endorse any particular cleaning method.

If a liquid cleaner is used, be SURE to dry the cases thoroughly to preclude corrosion inside. One method is to dump the wet brass into an old pillow case, then tilt it left/right so the cases re-orient themselves while shifting from corner to corner. Several repetitions, pausing at each corner until water stops draining, will remove most water. They can then be left to air-dry on a towel, or can be dried in a warm (150° F-200° F max) oven for a few minutes to speed evaporation.

3. Inspect Every Case
Once dry, inspect each case for significant deformation (i.e., someone stepped on it), damaged mouths/necks and case head/rim damage. Some rifles’ ejectors actually dig small chunks of brass out of the case head — obviously, not ideal for precision shooting. Similarly, some extractors can bend the case rims so badly that distortion is visible when spinning them in one’s fingers. These can be used for plinking, but our match brass should have straight, undamaged rims.

Dented case mouths are common, and these can easily be rounded using a conical, tapered tool, [such as a .223 expander mandrel. A dummy 7.62 or .30-06 cartridge with a FMJ spitzer can also work.] If most of your brass is of one headstamp, this is a good time to cull out any odd cases.

4. Check the Primers Before Decapping
Your clean, dry and inspected brass is now ready for full-length sizing, decapping and re-priming. Historically, primer crimps on GI brass have caused some head-scratching (and vile language) among handloaders. Our next installment will detail efficient, easy and practical methods to remove primer crimp, plus other useful handloading tips. Until next week, Good Shooting!

NOTE: The USAMU Handloading (HL) Shop does not RE-load fired 5.56 brass. We use virgin LC brass with our chosen primer already staked in place. However, our staff has extensive personal experience reloading GI brass for competition, which will supplement the Shop’s customary steps. In handloading, as in life, there are many ways to accomplish any given task. Our suggestions are note presented as the “only way,” by any means. Time for loading/practicing is always at a premium. Readers who have more efficient, alternative methods that maintain top accuracy are invited to share them here.

Similar Posts:

• How to Prep Once-Fired Lake City 5.56 Brass for Match Use
• How to Prep Milsurp 5.56 Brass for Match Use — USAMU Tips
• How to Prep Mil-Surp 5.56 Lake City Brass — Save Money
• Save $$ By Using Lake City 5.56x45mm Once-Fired GI Brass
• USAMU Reloading Tip — Prepping GI 5.56 Brass for Match Use

Tags: Brass Prep, Case Cleaning, Lake City, Reloading, USAMU, Wet Tumbling Brass