Trying to add ammo type to vanilla weapons

[KamSolastor]

Hello, everyone. Bit of a problem. I don't know how many of you have used the mod Angel Park, but it's a bit of an older mod that adds a new area, some new weapons, enemies, ammo types, ect. The only problem with the weapons and ammo is, the weapons added in it are all set to use ONLY the default ammo type for that weapon, and the ammo added by Angel Park [referenced as AP from now on]. Also, the ammo types are ONLY added to those separate ammo lists, so only these new weapons can use them. What I'm trying to figure out how to do is allow vanilla weapons to use the new ammo types, and allow the weapons added in Angel Park to use both vanilla ammo types and the new types. I have no experience with modding, and barely any experience in the GECK. Anyone know how to talk a newbie through how to do this?