MachineGun is a small Windows program/package which you can use to perform the chess problems solving competition. A number of problems is presented (ideally on a big screen) one by one to a group of solvers and they are expected to solve them within a given time, say 60 seconds, and write down the key. Then the controller collects the solution sheets and calculates the results.
The problems can be immediately shown again, this time with uncovered keys.
The program can be completely intuitively used, but there's also a short Instruction file, just in case...