I just finished making an automated gun using someone from Wellington's institute of technologies mini-gun style circuit which took some tweaking to get both the one at the top working with the one down below, I eventually moved the other one because I couldn't dig further to compensate for the circuit being built over with my stone. It is now a circuit that goes right around it and you'll notice that in this picture probably:
Oh and honestly, I know NOTHING about circuits to make my own unless I experimentally fix them for a large sum of time... You could say I know a basic part of it to make me go by and by the way I did not actually steal the whole design of his circuit, just the parallel clock, I think that's what you call it (correct me if I am wong).
EDIT: I have been working on my friends map for a while now and finally found out how to stop my minecraft from lagging, just needed to install Optifine 1.2.3