How this version will work;
This gun is powered by a large elastic that is hand cranked around a spool. The different mechanisms are linked to each other by gears. The blocking mech section of the trigger mech moves at half the rate of speed that the spool and firing mech move. This is because the blocking mech blocks every 180 degree rotation, while the firing mech needs to operate on 360 degree rotations. The gun uses an "alternating" semi-automatic trigger mechanism that unblocks one block mech, while the other remains in a blocked position. This ensures that no matter how slowly you pull the trigger and no matter how fast the firing elastic rotates the mechanism, the trigger will not fail to block the mechanism in exactly one rotation.
I'm still working on this version, but I got good results in previous versions. Upon completion, this will likely fire 6 rounds from a magazine 30 feet semi-automatically before re-cocking. I intend to take this design to the end, not stopping my work on it until it can function no better.
UPDATE: I've begun working on version 8. Turns out 7 had some problems. 8 will still include gears, an alternating trigger mech, and the same firing mech, but I'm totally redesigning the rest of it.