regular ammo vs ap ammo

[Brownfloaty]

I just started playing the beta this weekend and forgive me if this is answered somewhere else. I've been doing as much reading as I can to learn the game.

My question is about regular ammo and armor piercing ammo. The description for the regular says it is better against soft targets and the ap description says it is better against armored and vehicles. Does the ap ammo do significantly less damage against soft targets? Is there any real reason I should haul around both of them as opposed to just loading up on the ap ammo?