
I had once set something like this up for a APMine handweapon back in the early days of the GFMod where you still had to right click to arm the mine once fired. (the vehicle firearm would fire an invisible projectile that would arm the mine)
This worked without a hitch. Just make sure your new vehicle fire arm has the same mag size and reload time/fire rate as your main weapon and it should work fine. If the mag size/count doesn't match and one of the weapons runs out of ammo first, you can encounter a bug where your main weapon won't fire correctly. So be sure they match up!
