Its small - chamber only 1 foot of 2inch pvc - going straight into a ball valve to the breech and foot-long 1inch barrel. The breech is just an open coupling between the valve and the barrel, in which you place a 2 inch long 'shell'. The shell has 8 airsoft pellet-sized 1.5inch brass tubes glued inside in somewhat of a honeycomb. The back ends of the tubes are slightly pinched so that pellets dont come out of them. You fill the tubes in the shell w/ pellets, w/ wadding in the front so they dont fall out.
It pressurizes really quickly to upwards of 100 PSI, yet the performance is somewhat lacking - pellets kinda spray everywhere in a 15ft radius im guessing with a range of about 60ft.
I'll try to get pics up soon, but suggestions to improve performance would be appreciated - I'd especially like to hear about potentially using C02, or maybe a backpack refilling tank for quick reloading. I look forward to your feedback.
EDIT: Pictures





