I was in Rio Salado using some Hungarian Yellow/Siver tip ammo, a Ranger came by and asked if they are armor piercing rounds. I tell him no but I wasn't sure about the exact color codes so I look it up:
White: Steel Core
Yellow: Heave Ball
I went back yesterday and checked with them to see if it is ok to shoot Steel Core. The president and Range Master were both there. They said it is ok, Steel Core is not Armor Piercing
Just FYI.