I started yesterday building some reliable mini, And I finally did that by using a onboard-fuel injection... But I found that the chamber was to weak, too fat and there were some big rips where the barrel goes in. So I decided to scrap the fat chamber and go for a thick walled, thin long chamber with no holes (some gluestick containter).
Here's the result:
But since I'm using that chamber...It doesn't fire at all!!
I just can't get that mix right
It's true that I sometimes ajust the wheel that adjusts the butane flow but I returned it in it's original position I think, here's a pic of the fuel injection:
Maybe the insides got something to do with it? :
The cap where the piezo igniter is fixed on uses 2 nails that kinda 'float' above eachother, and are not next to eachother, does this matter? And since the whole chamber is from a gluestick, I can still smell the glue...does that change the athmosphere(?) or something? Here's another pic:
Oh and here's a size comparsion(?) of the 2 chambers...:
Would really appreciate help
I really wanna fire this thing off again (I miss smashing light bulbs with bb's... 
)
), I had the same trouble to begin with and here's how I fixed it.
I rather work with a butane lighter injection. Number 1 reason is that you don't have to mess with opening the gun, using things like spray's and syringes... And I also think it's alot quicker to prepare for the next shot. Actually the concept of this gun was to use it in a classroom, and I rather get busted with a mini spudgun, than getting busted with a mini spudgun, a propane torch, and a syringe 
In the classroom... How old are you?