It would be a pain in the butt, but you could theoretically use a script to do this...(I'm at 'work' so I'll summarize)
addeventhandler fired on the AH-6
have the script trigered by the addevent handler make sure the minigun is firing.
get the direction the fired bullet is travelling.
use the getpitch(or something like that) function get the pitch of the AH-6
use a drop particle (mainly to get a quick and easy relative position coordinate) with a lifetime of 0, and have it run a script when it 'dies' to camcreate a bullet;
the bullet would use setvelocity and sine/cosine (using the getdir)for 'forward' motion, and the getpitch to give it z axis velocity....a looooooooooot of math/trial and error etc later and your done!
or you could just live with one stream of tracers, your call