Brass...
Your right.. Crank will up the ROF.. But, as bad as that's jumping around, it would be hard to rotate the crank smoothly.. Need to get that tripod tied down. Crank won't work well when the lead sprayer jumps that much...
I've had the same thought. But to really test the crank, recoil must be eliminated. (whoo-hoo... eliminated

). OK as much as possiable
I'm going to weld a test stand to a set of tractor wheel weights. (yea, steel to cast iron weld.. That s*$ks..) Just a test... Let you know what happens..
Tim