interesting projectiles can be made from caulking gun cartriges. they can be had filled with an amazing assortment of splattering goo.(henry's roof patch is particularly nasty)

my searches have turned up little of value(i did find lots of links to find a lawyer , though) don't appear to be any state laws(yet).

for your double feeding problem, perhaps a small flat spring in the barrel to keep the ball from moving up the barrel until fired, thus the ball above in mag remains in mag. . for an electric valve, perhaps a shut-off solenoid valve for automotive propane systems. require 12V power source. BTW, i fi...

am new to this forum. built my gun 2 yrs ago. 2" pvc barrel, 6' comb. chamber, bbq igniter. favorite propellant: aqua net.
someone told me this week that potato guns had been outlawed in the people's republic of ca. any truth to this?