TexasCHLforum.com

For me the key parts are "46.01 (12) “Armor-piercing ammunition” means handgun ammunition that is designed primarily for the purpose of penetrating metal or body armor and to be used principally in pistols and revolvers."

It does not say capable it says designed primarily, and those are the key words... I think.
I have many rounds of hand gun ammunition in my gun room that are capable of penetration of threat level III soft body armor, but none of them were designed primarily to do so. Not advertised, marketed, intended as AP rounds.
I have Rifle rounds that are designed primarily as AP... and there are a select few "Hand Guns" that chamber these rounds.. but the ammo is designed, marketed, advertised as rifle rounds not handgun, so still think Im inside the law.