There are two that I know of off the top of my head. The first is a Freund patent #211,728 28, Jan 1879. You can find a copy of the patent drawing in Frank and George Freund and the Sharps Rifle, Pioneer Gunmakers of Wyoming Territory and Colorado by Gerald Kelver. It may also be mentioned in the Paco Kelly book. 
  The other one I believe was an entire action, like a Ballard but slightly smaller with the hammerless block. These actions were done by Arthur Hublak a piano tuner, gunsmith and bitter rival of Harry Pope in the gallery matches at Zettler’s . It is clear that Harry did not approve of the actions. What is not clear is why. With Harry once you were on his bad side nothing that was associated with you was any good.

40 Rod