I tested with 1/4 "and 5X steel balls, and the power is about half or one third, (1/2, 1/3), of what is achieved with that compression pressure and a rupture disc.
The reason is that much of the available energy generated in the mechanical work of compressing the spring, which is very hard, is spent. This is necessary so that the exhaust hole is not opened when compressing the mixture.
It shoots well, it is more powerful than a combustion weapon for ammunition of that caliber, but even in dreams the power of firing a hybrid can not be reached with a simple rupture disc, for that same firing cannon and that ammunition.
Logically, the energy used to break the rupture disc is many times less than that necessary to move the mass of the piston - guide - spring system, against the force exerted by this spring that is compressed.
In summary: Very simple to manufacture, easy to regulate, but with little force available to boost the ammunition.
Interesting experiment.
What remains to be proved is to minimize the mass of the piston assembly and the guide rod, and to leave the minimum and absolutely necessary force in the mainspring to be able to compress the mixture without opening the exhaust hole. I'll try this and tell you.
