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Reloading Primers


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I found this recently while trying to keep up with my reading; and thought it was worth sharing. It website links to a PDF authored by W. Marshall Thompson PhD, which is attached below. While I hope nobody needs this information anytime soon; might as well get it out there. Probably not something to mess around with if you don't have some background in chemistry (it's dangerous). 


One thing I found interesting, was the note about adding a touch of smokeless to weaker (easier to make) primers. Not sure I would have considered trying that without explicit direction.

Homemade Primer Course Update.pdf

Edited by Lane
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  • 3 months later...

Finally got the motivation to jump into this idea headfirst. Still not entirely committed to corrosive primers in most of my guns. But at this point; I figure it's little harm to dedicate a Savage Mark II to running corrosive loads... Certainly not able to buy a lot of new .22lr these days. 

The best guess I've seen about this particular priming compound, is that it is roughly H-48 compound... Ground glass, potassium chlorate, antimony sulfide, and sulphur. Certainly not a great price on the mix here; but I thought it would be interesting to try. Could apparently get something like 50x this for about $200 investment. (1 pound sulphur $4, 4 pounds potassium chlorate $80, 2 pounds antimony tri-sulfide $50 (should work), 1 pound ground glass (silicon) $20)=3628g). What I got was 26 grams PC, 18g AS, 14.8g Sulphur, and 5.5 grams ground glass (fine sand is what it looks like, for $20; which is only 65g total.

Perhaps some will see this as fools errand; they may even be correct. My motives remain unchanged though; and I think this is a great project to explore extreme weight accuracy in powder measurement. One could even try to weigh out priming compound; though I'm not sure I'll be overly concerned with that up front. I will weigh out each of the measured portions though; to see what the mix "really" is. The measurements certainly don't line up exactly with H-48 compound.

Initial inspection of the dual purpose .22lr casting/crimping tool, show it was CNC machined for the most part; and then hand adjusted with a file. There is still a bit of dust in the cavities from that; which needs to be cleaned out before smoking. It absolutely needs at least one; if not two wooden handles fabricated for it to be reasonably functional. Expensive for what it is, but I don't have a good way to make those projectile molds myself. Are they cut with a custom tool (sure doesn't look like ball end mill work)?

I've already messed with jamming a Lee mold cast 55 grain into a .22lr case. Seems to mostly fit; but won't chamber in my test rifle. Resizing might be the ticket though; and I've already got equipment for that. No sense letting a good crisis to go to waste (might as well learn something "new" while it's tough to find ammo/reloading components)...


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It appears I may had believed incorrect information about what this Prime All compound really is. It seems to actually be H-42; and not the H-48 I thought it was originally (and read other reviews guessing). That would certainly explain the odd weights of each bag in comparison to the H-48 recipe.

The forth bag is apparently powdered shellac (not ground glass). Immediately the next test was to see what solvent works best for that. I'm happy with acetone, and think it works better than 91% isopropyl alcohol. Going to try denatured as well, if I can find some in the garage. Acetone evaporates extremely quickly though, so I'd be curious to see if anything is is better in practice. Probably prime a few cases with each option... Others have suggested adding even more shellac in liquid form. So I'll try that too.

I cast a few projectiles, and while the mold works well; it has some quirks. Seems like it might even be designed for left handed users. Flung a few sprue cuts on the floor just trying to get the hang of it. And now double sure I need to make wooden handles for it. Even thick leather gloves weren't quite enough to keep my hands comfortable; as such, I only made a quick dozen.

Ground down the tips of a couple cheap punches and then hammered out most of the dent in a few dozen spent rimfire cases. While still imperfect, they seem to be a lot better. Now the cases need some cleaning, and resizing. Then I'll start loading rimfire primers. I may make a few small rifle primers too; but I don't currently have a gun picked out to use for that purpose. Apparently baking soda can be added to make the primers last longer (less moisture sensitive), so I'll give that a try if I make centerfire in any quantity. I also wonder if a final application of dilute shellac would make that unnecessary; maybe after the anvil is pressed in?

Images: Cheap punches before grinding, and .22lr castings. Tiny rails (floating on glass) of shellac powder before testing solvents.



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Took my time on the case prep for this; which is a delicate affair in comparison to larger brass. Mixed up a half batch of priming compound to the best of my ability; and loaded 10 cases. 

Five with acetone, and five with denatured alcohol. Ultimately I wasn't happy with 91% isopropyl alcohol for this. The denatured still takes considerably longer to evaporate, and packing the rim is more difficult as a result. One drop of acetone, and a short wait; made them pack pretty quickly in a noticeable way. 

Started testing a jig for centerfire primers, but it's not quite finished. It's a simple design, to hold large and small primer cups, and the anvil for each, so that priming compound can be pushed the recessed cups; and the anvil re-inserted. 

Reasonably confident in the results achieved; but will test them before making any more. It's really not that bad if you control your breath. A sneeze, or unsteady hand could make a mess real fast.




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  • 1 year later...

While looking into a new project; I came across a reasonable solution for making non-corrosive priming compound; EPH 20. Sure enough; the same W. Marshall Thompson seems to be involved. There are a number of videos on rumble and youTube showing various parts of the process. None if it appears to be terribly difficult or dangerous (though I did read somewhere that it's not entirely out of the ordinary to set one off when seating reloaded centerfire primers). 

The list of ingredients can mostly be obtained easily. The one catch is synthesizing your own lead hypophosphite, from lead nitrate and sodium (or calcium) hypophosphite. The other ingredients are (more) lead nitrate, ground glass, and nitrocellulose. The primer is activated as a final step by dropping 50/50 distilled water and alcohol on the finished primer. 

It will take me a bit to obtain these chemicals and get started myself; but I've watched the videos linked from the website, and overall it seems simple enough if you have the equipment and some basic chemistry experience. 


The new project for me, in case you are wondering; is reloading .41 swiss rimfire. Finding a viable method for reloading rimfire brass with non-corrosive primers make it a lot more attractive; and I'm happy to practice again on .22lr before I get to that point (I never wanted to shoot the corrosive .22lr primers I made in a gun I still use and appreciate). 

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  • 3 months later...

I've returned to this project. There are still a number of things I need to get my hands on; but nothing out of the ordinary at this point. 

Given the time that has passed; there have been a number of improvements worked out by other people. I saw just the other day; a set of tooling to punch and form brand new primer cups from brass sheet. That makes this even more attractive. 

There is even a spreadsheet calculator to aid in material purchasing and consumption. Just plugging in a few numbers I get prices like this...


Screen Shot 2022-11-13 at 3.18.21 AM.png

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Took the first steps in completing this EPH 20 priming compound. Do note; I'm doing this the absolute most difficult way. You can buy ground glass, and that will certainly save considerable time and effort.

I spent a number of hours grinding up 3.5 grams of borosilicate glass in a mortar and pestle. Turns out 3.5 grams is a rather ambitious amount; it's much faster and less work to do smaller batches if you do choose to make your own. In the second photo; all those "holes" you see in the powder are actually chunks, meaning there's a lot more grinding to get to flour consistency. Even when you think you're done, there's probably quite a bit more grinding to do... Third image is the final product at flour consistency.

Grinding glass is also kind of messy, it's essential to cover up the top as the glass is crushed. Even so, I was constantly feeling glass bits all over my work area and my clothes which I simply picked up with my fingers and added back to the mortar and pestle.

The next task was to make cakes of nitrocellulose which will then be ground up. You can use any kind of smokeless powder you have; maybe you have mystery pulls, or bench spills. Dissolve the powder in acetone (flooding over the top of the powder a bit, otherwise you'll end up with something chunky that might crumble apart) and then let it dry fully. Beware, when making aluminum foil boats too short..... The acetone has a tendency to move via capillary action. I had one boat wick out acetone/nitrocellulose and spill over despite not being even half full.

I left mine cakes on the baseboard heater for a while, then peeled off the aluminum foil boat, and back on the heater to dry some more until it is reasonably hard. If it's too soft, you'll end up with shavings that looks like rubber pencil eraser shavings, which are way too big. Finally, I clamped the chunk into my vise with a piece of paper to catch all the fine particles. Again; this took some number of hours to collect a few grams worth of ultra fine dust. Sort out any big chunks and store in an airtight container. 

Any larger nitrocellulose chunks that break off, or become too small to file down; can be saved and added to the next batch. 

The last (and most complicated) step before mixing actual priming compound; is synthesis of lead nitrophosphite. This actually requires a stirring hotplate, and some basic chemistry skills. Really, don't try to do this with hand stirring, there is a secondary reaction that absolutely must be avoided... My hotplate should arrive later today, so I'll post back when I have worked through that process and start making actual primers. 








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