I can see light passing between the piston and it's housing.
That isn't light its blue teflon tape I forgot to remove :)
EDIT: That isn't my piston either, Its the rubber washer I put infront of a metal washer.

About the chamber, I didn't plan for that huge volume. I bought the fire extinguisher ...

New piston is setting. Hopefully with the help of a little lubricant it will work.

also, is that a nail holding the rubber againts the piston?
if it is, you are rebellious, not to mention it is dodgy
Yeah it is, That was the result of my failed attempt at using epoxy :oops:

I presume the hose is your "air tank" which you use to help you maintain a muli-shot, without ...

No o-ring = no need for equalisation holes

Darn, I was kinda wishing it wasn't my piston. How could have MRR's have worked then?

Don't know the tolerances on your piston, but try a few turns of tape around it to get it more "snug" and try again.

Thanks for your reply.
The piston is a perfect fit in the tube apart from the equalization ridge I cut out. If I taped it, the piston wouldn't even fit in the tube

Hi again, I just finished my piston valve and gotten really bad results :( (100psi shooting a battery 3 metres) I thought the problem might be the piston being too short leaving alot of space for the piston to move back, but I put a new washer further forward behind the piston and it still continued ...

Thanks alot guys for the help
The fire extinguisher is the powder type and the hose connecting it is braided steel hose with a 20bar rating. So I should be all good with 260psi, I will buy the 1/2" to 1/4" Reducer JSR linked

Hi,
I'm making a pneumatic cannon out of mostly brass fittings that I have bought from bunnings. Its working out quite well but the problem is that they don't sell 1/2" to 1/4" adapters/reducers and I was wondering if they even exist? I've looked on ebay and other hardware shops aswell.
The reason I ...