"Weapons" 
No ammo: Knife
9mm ammo: Olg Magunm, Impactcannon, Hunter.
.756 ammo: Buzzsaw.
.50 ammo: Talon. (Note, Talon can be found only if u kil a Triad Officer ONLY!!!!! and Its Ammo!!!)

"Emenies"
Triad Gruad
Triad High Gruad
Triad Strike Team
Triad Officer
Dog

If u Pick up a weapon that need Diffrnet type of Ammo Change your weapon u will Find Ammo.