April 25th, 2023

Slick Tricks — Big Batch Case Lube Methods from the USAMU

In years past, the U.S. Army Marksmanship Unit published weekly reloading “how-to” article on the USAMU Facebook page. Here is a very informative USAMU article the subject of case lubrication. Tasked with producing thousands of rounds of ammo for team members, the USAMU’s reloading staff has developed very efficient procedures for lubricating large quantities of cases. This article reveals the USAMU’s clever “big-batch” lube methods. For other helpful hand-loading tips, visit the USAMU Facebook page on upcoming Wednesdays.

Rapid, High-Volume Case Lubrication

Today’s topic covers methods for quickly applying spray lube to cartridge cases prior to sizing. A typical order for this shop may be 25,000 rounds, so [speeding up] the lubrication process can be a real time-saver. While your ammunition lots probably aren’t this large, the efficient methods discussed here may help save a considerable amount of time over your handloading career. Our case lubrication rates range from 1500-1600 cases per hour, to 2400-2500 cases per hour, depending on caliber.

This shop uses virgin brass, whereas most home handloaders use fired brass, which necessitates some small changes at times. These will be discussed as they arise. Begin with fired brass that has been tumbled clean.

Ensure as much tumbling media as possible is removed from the brass, as when it gets into a size die, it can dent cases significantly. This is a good time to round out dents in the case mouths using a tapered tool to prevent damage from the decapping stem.

First, dump the clean cases into a large box or reloading bin. Shake the bin back and forth so that many cases are oriented with the mouths up. Next, pick up as many cases as is convenient with the mouths “up”, from natural clusters of correctly-oriented cases. With 7.62mm-size cases, this is usually 3-4, and with 5.56mm cases, this can be up to 8-10. Place the cases into the rack slots, mouth-up. Doing this in groups rather than singly saves considerable time. Once these clusters have been depleted, it will be time to re-shake the bin to orient more cases “up.”.

This photo shows a case lubrication rack made by a USAMU staffer.

Naturally, adjust the spacing to best fit the calibers you reload. We have found this size … convenient for handling through the various phases of case lubrication/transfer to progressive case feeders for processing. Note that the 1/2-inch angle does not cover much of the critical case area at the base, just forward of the extractor groove, where most re-sizing force will be exerted. As the USAMU uses virgin brass, less lubrication is required for our brass than would be needed for Full Length (FL) sizing of previously-fired brass.

NOTE: The amount applied using our rack is easily enough for our purpose. If using fired brass, be sure to adequately lube this base area to avoid having cases stick in the full-length sizing die.

Using a spray lube, coat the cases adequately, but not excessively, from all sides. Be sure to get some lube into the case mouths/necks, in order to reduce expander ball drag and case stretching/headspace changes. The spray lube this shop uses does not harm primers or powder, and does not require tumbling to remove after lubing.*

Take a close look at the photo above. The USAMU shop uses a common kitchen turntable, which allows the rack to be rotated easily. We place this in a custom-made box which prevents over-spray on to floors and walls.

Angled Box Method for Smaller Cases to be Neck-Sized
A refinement of the above method which especially speeds processing of 5.56x45mm cases is as follows. A small cardboard box which holds about 100 cases is fitted with an angled “floor” secured by tape. With the smaller 5.56mm cases, usually about 8-10 cases per handful can be picked up, already correctly-oriented, and placed into the box together. This prevents having to place them into the rack slots, saving time.

HOWEVER, note that this does not allow nearly as much lube access to the case bodies as does the rack. For our purposes — neck-sizing and setting neck tension on new brass, this works well. If using this procedure with fired brass, take steps to ensure adequate lube to prevent stuck cases.

As always, we hope this will help our fellow handloaders. Good luck, and good shooting!

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*A two-part test performed here involved spraying primed cases heavily, while getting more lube into the case mouth/body than even a careless handloader would likely apply. The second part of the test involved literally spraying considerable quantities of the lube directly into the cases, drenching the primers. After a several-day wait to allow the lube to penetrate the primers, they were then fired in a test barrel. All fired normally; no unusual reports were noted. This bolstered confidence that normal amounts of the lube would not adversely affect our ammunition, and we have been pleased with the results over several years.