I can't believe I just saw this gizmo.
I picked it up at Cheaper Than Dirt for under $20 and just came from the range. It really works. I don't have anything bigger than a 10 rd. mag yet, but still, what fun! It came with a copy of the letter from BATF stating that this was
NOT subject to Class III/NFA restrictions because it only fires one round per trigger pull.
In fact, it's not just a sprayer. My 10/22 has so little recoil, that I can actually aim it from my shoulder with this gizmo on it and get the rounds on target. It fires as fast as you can crank it and no slower than a full auto. What a great find. I can buy a pallet of 10k rounds of .22 for way less than 1000 rds. of .223 costs me. And one of these days when I go shoot out in the desert, I will find a way to rig this to my M4. All I need is a good bipod now and I have a legal Gatling gun.