For 1/4" and standard BB rounds, what kind of muzzle velocity are you looking at when the guns are passing the foam test?
The ausbg limits max velocity to 165ft/sec. We dont use the foam test at all anymore since there are now cheap reliable chronographs available.
Can the chronographs clock multi round cannons like the Indiana cannon? I know normally if there are 3 barrels, there are usually singer and weaker ones.