Ok I found the game book that described gun- fu that I was thinking of. It is in the Aegis handbook for conspiracy x first edition (I think)
it is described as: “a modern close combat technique that uses a pistol as an extension of the combatants body students of gun- fu Train using pistols in much the same way that students of other martial arts is more traditional weapons/…/ character skilled in the martial art may add the moves draw pistol, shoot, and pistol whip to martial arts and brawling combos along with the other usual moves. when these moves are performed the character uses his gun- fu skill level to determine the success rather than his martial arts or brawling skill. /…/ gun- fu may only be used in close combat at point blank range.”
As far as my imagination goes the best implementation that I can think of would be a skill book. Something like a “CIA Close combat manual” (this is in America after all so, sorry gign/gsg9) that would give some hand to hand moves that were focused on power (high damage) but were lacking in defense. every movie I have seen that uses gun-fu the hero just seems to keep soaking the damage until he wins or is killed.
The way I could see this working would be to treat the “Gun- fu” as a high damage, zero/negative defense stance requiring you to be wielding a loaded gun. The “special” moves would use at least one round but would add the weapons damage to your strike. To try to counter balance this I feel we could have it be that “smaller lighter” guns have a higher chance of activating the specials.
This was all just a loose idea I honestly don’t know if I have enough skill to even make this work. The biggest project I have coded was a profession that I have not even finished yet.
Edit.
I was thinking more of the “press the gun to a meaty portion of my enemy and pull the trigger” (ala John wick) version of gun fu than the equilibrium “stand in the middle of a room and don’t get shot while shooting everyone else” (like equilibrium).
If I could get some more information about skill and stance books I could give the bayonet and but thing a go but as my knowledge and skills stand I would have to shop out the advanced work. 