The recent unpleasantness in Japan piqued my interest in DIY firearms and electronic ignition, which led me to the Remington Model 700 EtronX, which was introduced in 2000 and discontinued in 2003. Ian of Forgotten Weapons explains:
It consisted of a standard Remington 700 bolt action rifle, with the trigger and firing mechanisms replaced by electric versions. The firing pin itself became an insulated electrode, the trigger operated an electronic switch instead of a mechanical sear, and a 9V battery feeding a capacitor provided the energy to ignite the new type of primer — basically a resistor that would generate heat to ignite a charge of smokeless powder.
[…]
Unfortunately, the only practical advantage to the electronic workings was a reduction in lock time of the action (the delay from trigger press to cartridge ignition). They did in fact achieve a virtual elimination of lock time, but this was not a problem that needed to be addressed for the general sporting rifle market.
Now, if they introduced a gun that didn’t need conventional primers today, they might have some success.
One hobbyist found it surprisingly hard to ignite gunpowder:
Experiments performed a few years ago and shown on the web page here found that weak sparks, such as from static electricity, are incapable of igniting black powder. Since I wanted to use smokeless powder in the rifle, and since it has a much higher ignition point than the black powder shown here, my first attempts used sparks from a stun-gun to see if they could ignite the powder.
The stun gun shown here is advertised as producing a 100,000 volt spark. The sparks were certainly loud and impressive, and they easily burned tiny holes through a piece of paper placed between the electrodes, but would they ignite powder?
Hundreds of sparks were struck into a pile of Hodgdon’s Tite-Group smokeless powder (left) and Swiss black powder (right) with absolutely no effect except for bouncing the grains around. The sparks were striking the grains, and you can see flashes when the spark hits the surface of the granules, but never once would the powder ignite!
The photo below shows a spark from the stun gun going completely through a line of black powder stuck to a piece of masking tape, and although hundreds of grains were simultaneously hit, nothing happened.
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About this time I was ready to give up, but after a few days of reflection, I thought I knew what was happening. The spark in the chamber was clearly extraordinarily hot and was vigorous enough to blow the tamper out of the chamber, which meant that the air in the chamber had to be heated to a high temperature. But why didn’t the powder ignite? I believed the reason was the extremely brief duration of the spark; in trying to capture it on a video, it was so brief that it took many tries to accidentally capture a video frame on a camera running 30 frames/second. My guess is that it lasted only a few micro seconds, and thus, no matter how hot it was, it couldn’t transfer enough heat into the powder granules during this brief time period for them to ignite. Therefore, slowing down the spark, even if it meant reducing its intensity, might be enough to do the job.
To slow down the spark, I simply added a resistor in series with the capacitor so the current was limited to about two amperes — which is still a lot of current going through a spark. As you can see from the image, the spark was much brighter than from the spark coil alone, but was very much less intense than without the resistor. However, it seemed to last a bit longer — about 2000 micro seconds, so that elongation might do the trick.
I added some smokeless powder (this time without a tamper) and sparked it. It worked! Not only did it work for the Tite Group smokeless powder, but for all others I tried, and all ignitions were instantaneous.
Electric ignition of propellant is interesting, but it’s a solution in search of a problem.
“it’s a solution in search of a problem”
I found the problem:
https://www.19fortyfive.com/2022/05/trying-to-reload-your-own-ammo-there-is-now-a-primer-shortage/
Mike in Boston notes the problem that electric ignition could solve today: there don’t seem to be enough primers to go around.
Electric ignition solves other problems though. First, it means you can make a trigger as light as you’d like, with no loss of reliability. Further, you can place that electronic trigger anywhere you want; it doesn’t have to be right next to the firing mechanism. This make a “bullpup” rifle more practical. Unfortunately, since it also makes fully automatic fire easy, no one wants to produce a semiauto gun with electric ignition; its legality would be in question.
The EtronX had primers, but the primers were different than those used in standard cartridges. It was never about primerless cartridges but eliminating the lag time of the mechanical trigger and firing pin system.
https://www.thetruthaboutguns.com/electric-cartridge-primers-gone-but-not-lamented/
They are no longer available. Any gun requiring EtronX ammo is now a club unless it is rebuilt to fire standard cartridges. The system is anything but a solution to today’s primer shortage.