Are we working with a 1/2 to 1/4 black pipe reducer on the end? So basically a .540 muzzle?

Are you planning on using back powder or smokeless powder?

Now i kind of want to leave work to see if i can ignite smokeless powder with a 9v battery and some leads.

I know you are down for ideas, you already have a fire extinguisher ready to put out some scientific freedom if need be.

Yes, steel wool will make for an excellent ignitor and won't take much to make glow almost immediately using 9v.

A ghost gun with an electronic trigger. Love it.

What could possibly go wrong?

Man that is freaking awesome!

Awaiting results

Lol

Keep us posted

I think your chamber volume is too large. It's not like an immediate leade taper where a bullet goes down a rifled barrel. The whole pipe is a large chamber and blast energy is virtually lost throughout and around the ball within the whole pipe interior.

Need to make the chamber much smaller for the firecracker to use its energy to propel the ammo balls you're using for better effects. Try some copper pipe smaller than the iron pipe's interior diameter and make the pipe longer to stick out the end where the muzzle cap will screw over the copper pipe and hold copper pipe in place. Just like a barrel sticking out a free floating handguard, but in this instance you want the copper pipe to be held snuggly in place by the pipe threads, while the rear of the copper pipe goes just to the rear of the butt area to remove the end cap and install the firecracker.. Some reaming of muzzle threads might be needed to accomplish this.

If this improves what you're looking for, then get some even smaller copper pipe to place within the previous pipe, as long as the ammo balls will fit into. If too large of space between the copper pipes, JBWeld the pipes together to hold them in position (especially the rear side to not let gases escape between any of the pipes. You want the balls to just slide in "snug" to not fall out (paper or tissue wrap might be needed, but NOT rammed in like a slug in a black-ball powder pistol.

The smaller the interior diameter the better explosive force that firecracker will give in launching the ammo ball. Only one way for that gas to go and that's forward, with a tiny bit of energy going out the fuse hole..  

What about O-rings to keep things centered and sealed? Easy to disassemble when needed also. Cheap and effective from that point on when you know what size to use. Harbor Freight carries them in a variety size box of either Millimeter or SAE.

Imagine getting capped with a roofing nail fired by a gun using firecrackers.

What size I.D. you looking for? There's stainless/steel fuel line, brake line for vehicles, or larger hydraulic/fuel metal lines for tractors/construction machines in different sizes. To keep costs down, find a salvage yard. They might have something.

There's also Lowe's/Home Depot/Menard's that carry "chromed" (go pimp for the barrel) plumbing pipe(s) that would handle a firecracker (or 3).

Have you tried/looked at any softer plastic water/plumbing pipe to see if you could slip any of that within the metal pipe to make a sleeve that could work? The metal outer pipe will hold the pressures that the plastic won't by itself, but together that plastic will work. Might be worth a try.

Freaking cool

Looking forward to range report.

Very neat.

Well done sir.

Now you need to turn it into a magnum. For scientific purposes. Do they make crackers hotter than Black Cats but not as powerful as M80's to try? Maybe 2 crackers in the chamber.