adjusting rapidfire with a potentiometer

[Winterz117]

i did sillynuts's mod with the 555 timer and it works great...for call of duty. i also play halo tho. somebody said something about using a potentiometer to adjust the fire rate so that its not too fast for halo, and im thinking im gona figure this out. im thinking a 10k ohm linear taper pot, but theres also audio
taper and audio control (i figured those were wrong cuz it says audio...) can anyone verify this before i go and buy parts?