YACC (Yet Another Combustion Cartridge)

[ALIHISGREAT]

As JSR said, you need at least a 1:1 ratio, so i think you're looking at this the wrong way, i think to get decent performance, you have two options:

1)hybrid cartridges - more dangerous but more powerful.

2)Using cartridges for the propellant, then having a separate loading system for the ammo - this enables the possibility at least a 1:1 ratio.

[jackssmirkingrevenge]

The third option is a bottle-necked cartridge

[psycix]

In that GIF the chamber seems to slide in freely, and is thus also able to slide out freely too. Which can be dangerous as you dont want your chamber or barrel flying off in a somewhat unpridictable direction.
Be sure to lock it down.

[jackssmirkingrevenge]

I had made that to illustrate the concept, in practice the cart would be held by a spring-loaded bolt and strike and ejector on its way out of the breech to eject it sideways. And what do you know, it works

[youtube][/youtube]

This was my original breech design, more details here.

[mega_swordman]

A lot of quick replies. Alright

2)Using cartridges for the propellant, then having a separate loading system for the ammo - this enables the possibility at least a 1:1 ratio.

I plan on having the cartridge connect to another longer barrel, so the 1:1 ration should be solved by that.

- Too many studs jutting out of the cartridge body, not conducive to smooth feeding if indeed you plan a feeding mechanism

At this point I am going to use the cartridges as a single shot, like rockets in a rocket launcher. A cycling system would come later.

- Using a syringe, adding fuel through the mouth of the cartridge is a perfectly good way to fill it.

I think I'll consider this. What I could potentially do is have a pvc endcap that connects to the front and still use homedepotpro's fuel meter (drawing to come soon).