Making 7mm caps

I modeled up a 7mm MGC cap in Fusion 360. I'm trying to load it with prime-all. I've tried a few, but none of them have ignited.
https://www.thingiverse.com/thing:5173750

Prime-all can be shipped without restrictions because it isn't considered an explosive. It comes with 4 separate bags of powders. The powders get mixed together to make the priming powder.

I'm not entirely sure why they aren't igniting. I do have a few theories. Hopefully with some more testing I can get it to work.

When I loaded them I filled to the top with powder then added acetone and tamped down. I waited 24 hours like the directions said. I also tried a week later. That should have been more than enough time to dry. It might be because I have too much powder.

Some people who have used prime-all for reloading primes have topped them with a paper cap. That might help with the ignition.

It might be that the plastic is too soft. The cap might need to be made of metal like a percussion cap. It might also work with a metal disk on the inside.

never heard of this stuff, very interesting just watched a youtube vid and it works well in a real gun. I highly doubt that this can be bought in the UK and if it can i would think you would need a firearm licence to buy it.

Interesting compounds.

My initial guess would be the surface area of the piston pin doesn't give the required force to set it off. Some have used it for percussion cap reloads, but that will be metal (cap) to metal (pin) when struck.

My second thought would be "how dangerous is this stuff when mixed into the quantities needed for a 7mm cap" Explosion risk when dry and the chemicals given off when ignited.

Stay safe.

8ace

I wonder if prime all is available in the EU.
Also it is a good thing to save fired caps for a later refill.

I've done something similar with the exact cap model

instead of using prime all, I've used the powder in paper caps, perhaps adding a layer of the powder could ignite?

I came across this clip of a guy making caps for a real steel muzzle loader



Wondering if it could work in a model gun ??
There might be a need to run a test if 9 charges is right
Anyone feel like testing ?