The problem with any semi auto combustion is exactly what you see here, they're weak as hell. If he could get this gun to decent performance I'd be impressed. Not knocking his design, it's quite a feat. It's just hard to get enthusiastic when I could throw the ball further than that, faster too.

Nice...

Sounds like your gun has a bit of a flatulence problem, might I suggest:

It's easily sealable with most high end epoxy. Just sleeve it with PVC of a larger bore on the outside. Use electrical tape or foam tape to make up the gap between the PVC and steel conduit and the use the epoxy to fill in the gap between. Steel electical conduit is just steel pipe that electircians...

You need to do some serious research friend. As much as I want to help you if you don't even know how to seal a chamber you are in for a rude awakening when it comes to the mathmatical and engineering complexity of one of these things. Might I suggest looking at the spudwiki section first.

No they hold a very stable trajectory well beyond 50 yards. Any ammo becomes very difficult to aim past 50 yards though and darts are no exception. By the way don't use PVC on your barrel it's far too floppy and inaccurate. Intead try steel electrical conduit.

did you check my signature? It has many answers for you.

The better answer is multiple gaps spaced evenly through out the chamber.

I don't know how fast it will shoot a marble. I hate marbles. Terrible ammo, inaccurate, poor penetration due to light weight and when they explode you basically get a cloud of glass dust. Not so fun to breathe in. Personally I have quit using marbles all together. As far as your chamber question I ...

spoiler alert: my gun currently uses a burst disc and Mapp it's absurdly powerful. Quite honestly this isn't a weekend project type thing to get this kind of performance while safety is important you are not being logical here. schedule 80 is hard to find and entirely unnecessary, steel is small and...

That's unnecessary sch 40 pressure rated PVC is more than adequate for any standard combustion. Check my sig as it matches the general description of what you want to do with your gun.

First rule of life and spudding, more does not = Better. More is more. If you want better performance try using a higher tech approach. Are you using hairspray? If so try a more advanced setup like propane metering. You WILL get better performance there. Fan, stungun ignition etc. I will go into mor...

Quick plasma question, does the resulting "exhaust" condense into aluminum oxides or some other aluminum derivative? Or is the plasma hot enough to actually separate protons, neutrons, and electrons into different elements ala fusion? I know a lot of very weird things happen in this state.

Wow sorry I irritated you so much. I was just stating that neither a metered setup or your propane air nozzle will do anything to actually insure an even mixture once the fuel is injected into the chamber. I'm not sure I understand your method and perhaps you don't understand what I'm trying to conv...

That still does not insure an even mixture, it insures a fixed amount of propane in the chamber.

Your mixture will be far from precise just because you put a propane air mixing torch head in the chamber.