So I'm building a gun.

For the moment its just a proof of concept.

Ammunition is too hard to come buy here, so I've made my own "cartirdges". They are simply thin Al tubes with granulated blackpowder and a lead ball glued to one end, the other end is just a cover of tissue paper.

Now, because I don't have primers, the powder is ignited by a red-hot loop of wire attached to the front of the bolt.

The wire punctures the paper, ignites the powder and away the ammo goes.

The bolt is spring action, you pull it back, it locks into place, and when you pull the trigger the bolt flies forward, igniting the powder, and at the same time sealing off the back of the gun from the exploding gases.

The question IS:

How does a real gun work to get a good seal? The ammo if firing quite nicely, but I keep getting blowback. The seal between the barrel and the bolt isn't enough.

I'll get some pictures up when I get home.

lol. that gun must suck. i mean essentially it's a musket. you're firing lead balls, and i bet the barrel doesn't have those grooves that makes the bullets spin sideways instead of forward. that's a fucking musket. the accuracy must be so bad.

It's accurate for about 50meters.

And it can fire 10 shots a minute with the bolt action mechanism.

And it cost me $10 for a reel of welding material.

the reason you are not getting a good seal is because you are(it sounds to me) trying to get a breach loading system, and having the back of the bullet exposed for a sec

heres my elementary diagram

the firing mech )- () fhe back of the bullet
)- ()
)- ()
)-()
the red hot wire hits and goes through the flimsly thing first, and those chems will reasct a hell of a lot faster than the rest of the seel getting into place.

Yup.
Cerberus hit the nail on the head.
The wire ignites the fuel before the seal is completed.

I need some way of getting the breech into a sealed position BEFORE the wire ignites the fuel.

And that right there is why Australians suck, I could build a better gun with my dick...

use a moveble block with a hole through it and get the wire in that hole.
A real gun uses this but then with a pin instead of a wire.

Why don't you mail order ammo? .22 is 10$ for 500 rounds. IT 80$ for 1000 .223 which is a great round. 9mm is about the same. I recently bought 3 books on a .22 and a 9mm submachine gun. Real guns the shell is tapered so it makes a full seal. Try having the bolt land home and then the momentum would cause the wire to fly forward into the ammo. so it basically works the same as a firing pin. except no spring just momentum pushing the initiation device

Is ammo really that cheap? My custom 8mm rounds cost $1.20 each, that's 60 times as expensive as a .22, damn :shock: