-at round start, pressing reload would buy ammunition for the weapon currently in your hands... for mix-n-match pistols, holding reload and pressing fire or altfire would buy ammunition for that pistol (same as reloading ingame)
-i found it a little confusing that if you have a pistol and a shotgun/rifle/gatling gun, the pistol ammunition is "primary ammo" and the ammunition for the latter is "secondary ammo." to me, my primary weapon is the one bound to the 3 key, not the 2 key. perhaps something better would be "primary ammo" and "pistol ammo"?
p.s. i don't know how that would work when you have two different pistols and a third gun! haven't even thought about that yet :o