I used 1.0 BETA, but I believe v2.0 has the same location
-Go to the directory of the weapon you want to change (ex. AK47)
ame\garrysmod\garrysmod\addons\Mad Cows Weapons\lua\weapons\weapon_mad_ak47”
-Open up “shared.lua”
Edit the line
SWEP.Primary.Ammo = "StriderMinigun"
and change it to
SWEP.Primary.Ammo = "SMG1"
Now you can buy ammo for the AK! You have to do this for all the weapons, however.
Pistol SMG1 Buckshot
(Buckshot is shotgun!)