Is it possible to create multiple ammunition types for a single weapon? I recall the original games possessing multiple ammo types (for example, both Jacketed Hollow Point and Armor Piercing rounds were available in the 10mm format) with each type altering the effectiveness of the guns they were used in (for example, JHP was ostensibly poor against armored targets while AP was bad for unarmored targets, though in practice AP was just plain inferior), which might be an elegant solution for power armored enemies being perceived as too vulnerable to small guns - just switch to armor piercing rounds for the metal monstrosities and use your normal JHP or FMJ rounds for everything else!
Closest thing I've seen is the grenade launcher mod which uses 3 types of ammo: http://www.fallout3nexus.com/downloads/file.php?id=2286
However it's not really a single weapon, it's 3 weapons alternating between 3 changer scripts. Still a very cool weapon though. As for AP rounds, CALIBR has some entries and schematics for AP rounds that "ignores normal weapon resistance", which effectively negates armor. If Mezmorelda has a DR/power armor revamp in mind (hope so
)so that heavier armors are almost impervious to small arms fire, small guns characters could make use of this ammo type to good effect I would think. If the armors are getting an overhaul, this type of ammo should be very expensive to purchase/craft, and more difficult to find I would think, otherwise once again the armor is useless. Many many things to account for when balancing...almost mind boggling at times.