hi!
When JSR got the mini-hybrid working on high-mixes, i decided that i want to build something like that. Well today i had time and went to my workshop. Then i saw an old .177 cal airgun barrel. I got an idea, and here it is. Basically i drilled 11mm dia hole about 34mm deep and i left few inches long barrel. the combuction chamber is 11mm x 24mm, so its not big

. The small screw on the top is for the iongition and has 1mm hole thhrough it, and after i took the pictures i epoxied a wire to it, it has about .1-.2mm spark gap and i can adjust it if i need. I tapped screws to the bottom of the combustion chamber to alloy me to plug it with a bolt. Today or as soon as i can ill epoxy a presta valve to the bolt so i can feed this baby

. heres a picture of it
EDIT: heres one more pic