Everything You Ever Wanted To Know About Making Percussion Caps and Primers But Were Afraid to Google

Guns aren’t hard to make. Third world workshops and first world hobbyists routinely manufacture firearms using both common and exotic materials, by methods as varied as simple hammering all the way up to 3D printing. Many who promote gun control understand the ease of firearms production and suggest that ammunition is the best “choke point” for disarming civilians. They operate under the assumption that ammunition is difficult to make. Like so much about guns, they’re wrong.

Projectiles have been made in the billions by hobbyists for hundreds of years. Ammunition cartridge cases can be reused a hundred times or more, and they’re not terribly difficult to manufacture. Gunpowder can certainly be made at home easily enough.

Ah, but what about primers? As wikipedia.org informs:

In firearm ballistics, the primer (/ˈpraɪmər/) is a component of pistol, rifle, and shotgun rounds. Upon being struck with sufficient force, a primer reacts chemically to produce heat which ignites the main propellant charge and fires the projectile.

There have always been a few dedicated hobbyists who have recharged primers. Before the internet, that information didn’t make it into the mainstream. During the Cold War, I knew of Soviet hunters who recharged their shotgun primers with the tips of strike-anywhere matchheads. That method is detailed in the Army manual on improvised munitions, TM 31-210, page 297. The problem is it’s slow and labor intensive. It takes several minutes to recharge a single primer.

The Tap-O-Cap is a tool that was made by Forster. It can make usable percussion caps from aluminium drink cans and cap gun roll caps. Recharging primers is now, again, a thing. That’s as a hundred million additional firearms have been added to the U.S. private stock since Mr. Obama assumed office.

At the same time, consumers bought and stockpiled perhaps, by some estimates, a hundred billion rounds of ammunition. Reloading supplies, including primers, became scarce as demand skyrocketed — along with prices.

A great many Americans “suddenly” want to reload. On several forums on the internet, sophisticated and knowlegable enthusiasts began exploring the possibility of recharging percussion caps and primers.

The results have been extraordinary. There’s now a thriving community of hobbyists (e.g., castboolits.gunloads.com) who share what works, what doesn’t, and how to obtain or make the necessary materials to make, reload or recharge primers and percussion caps. There are, of course, plenty of Youtube videos on making percussion caps and recharging primers.

Safety precautions have to be followed. My estimate of the risk is about the same as the hobby of reloading cartridges. It’s less dangerous than scuba diving, sky diving, or horseback riding. The materials aren’t hard to acquire and can be made from common household chemicals. It’s easier to purchase them directly.

Because the amounts of priming compound necessary to recharge primers are tiny, small amounts of chemicals are sufficient for thousands of primers. One pound (454 grams) is sufficient for between 14,000 and 23,000 primers. A small pistol primer takes about .3 grains of priming compound; a large pistol primer requires about .5 grains. There are 7,000 grains in a pound, or 15.4 grains in one gram. Do the math.

W. Marshall Thompson, PhD has created a course that offers the best instruction for recharging primers and percussion caps. The course developed by Marshall Thompson is available for free download at this link.

As a seasoned academic, Dr. Thompson researched the published material before he created the course. He has several years of practical experience in doing what he explains. His work is wonderfully detailed and complete. It offers several methods for recharging primers and two variations, with less detail, for creating percussion caps.

The course starts by discussing the history of primers and the requirements for a successful primer. It discusses the basic legal issues. Then it goes into the details of how to recharge primers if you have the desire and/or the necessity of doing so.

In a forum, Marshall has acknowledged that recharging primers is not economic when commercial primers are readily available. That is not the point, he says. If the knowledge is available now, and people develop the skills now, it will be available when and where it is needed. It is extremely satisfying to create and/or reload your own primers from basic materials.

Here are the four most practical methods for recharging primers:

1. The cap gun roll cap method

This is the easiest method, and works fairly well for pistol cartridges that use fast burning powder. The primers made with this method may not be energetic enough for reliable ignition of slow burning rifle powders.

Marshall lists which cap gun caps are the best. He details the procedure of recharging the primer cups. He diagrams how to recharge the primers with the caps. With practice, a couple of primers a minute can be produced. These primers are corrosive.

Marshall’s son in law recently tested 50 9mm cartridges.  The cartridges were loaded with cap gun roll cap primers three years ago.  They all functioned as normal reloaded cartridges.  There were no failures to fire or feed.

2. The strike-anywhere match head method (detailed in TM-31-210)

It produces a bit more energetic primers, but is much slower to use. It requires about 5-10 minutes for each completed primer. These primers are corrosive.

3. Duplicate the priming compounds used by the U.S. Army before, during, and after WWI

These priming compounds are very energetic, very stable, and have an extremely long shelf life. They are corrosive. They are not hard to produce, requiring only 3-6 components (there are minor variations).

The components are mixed dry, in small batches of 2 grams or less, for reasons of safety. The priming mixture is moistened after it is loaded into the primer cup. Then the anvil is installed. The primers produced with this method are very close to commercial primers for reliability and shelf life. Careful production of primers can be done at the rate of almost one a minute.

The primary chemicals used for the U.S. Army compounds are potassium chlorate (KClO₃), antimony sulfide (commonly known as stibnite, Sb₂S₃), sulfur, ground glass, sodium bicarbonate (baking powder), and powdered aluminum.

Perfectly good primers can be made with just the first three materials. The others are used to assist in long term stability and ignition of slow powders. A dilute varnish/water/alcohol solution is commonly used to wet the mixture and as a binder. Combining the chemicals and assembling the primers is a simple recipe based process that does not involve any chemistry.

4. Create your own precursor chemicals

The advantage of the method is that it produces excellent quality, non-corrosive primers. If you attempt this method, you need some basic wet chemistry skills, about the level of a senior high school or college freshman chemistry class.

This method requires the manufacture of precursor chemicals that aren’t easily purchased in normal commercial channels, to make non-corrosive priming compound.  The precursor chemicals involve some risk, so the wet chemistry synthesis procedures need to be followed strictly.

Once the precursor chemicals are created, the recharging of the primers duplicates an old Ely priming method (whose patent has expired). The synthesis of the actual priming compound occurs in the priming cup, after the dry mix has been moistened. The priming compound is activated as it dries out, making this one of the safest methods for placing the priming compound in the cup.

The dry mix is not very sensitive. It can be  produced from the synthesized chemicals with a fair degree of safety. It can be stored safely in small batches. After the dry mix is produced, recharging the primers takes a little over a minute each. Simple small batch methods may help increase production, but safety requires that no more than a dozen or two primers be recharged per batch.

The recharging/reloading, or even manufacturing of primers is well within the capability of the average hobbyist. Two years ago, I would have thought it impractical to the point of impossibility. Now I know better. It is information that deserves a wide audience. Marshall Thompson, PhD, and anonymous Internet publishers deserve much credit for their efforts.

©2016 by Dean Weingarten: Permission to share is granted when this notice is included.
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