In 2014 we used a disc brake on our shooter winch. We wanted a fast cycle time between shots, less stress on our dog shifter while firing, and most importantly control over the shooter for safety.
The cable coming from the gearbox was connected to a locking piston mechanism that was larger than it needed to be but it did the job well and was a designed by some freshman students and made primarily on a bandsaw and drill press.
Pictures can be found
here.
Video of them in action
here.