One of the things we have heard people having problems getting the interuptor pin set correctly after disassembling the cannon for cleaning or maintenance. While I am not an expert on this yet, I have found this method of setting the interruptor cap to be fast and effective. This process has to be done without an o-ring at the base of the barrel (and will not work at all with a geek breach).
1. Screw the interruptor cap all the way in (without pinching the pin itself).
2. Fill the magazine with BBs and cap the magazine.
3. Position the cannon as shown in the picture.
4. Slowly unscrew the interruptor cap.
5. As some point, a number of BBs will fall out.
6. Further unscrew the cap by 1/8 turn. The position is now at least very close.
7. Test the guns in this configuration to make sure a single shot is fired each time (adjust as needed)
8. Secure the cap with Loctite (blue is preferable) to keep the adjustment stable.
9. Test one last time before the Loctite sets.