The FPD line has a few added features desireable in carry ammo
1. Nickle plated cases. Stay nice, clean and smooth longer than non plated brass
2. Flash retardant powders. Generally triple base powders that have very little muzzle flash. Less affect on your night vision and does not give your position away as easily.
The bullets are likely standard XTP's which are pretty good bullets. I would consider them on par with Golden Sabres and nearly as good as Gold Dots and Hydra-shocks.