AP .303 exists. I have some, and I know an Enfield collector who confirmed its existence to me. Black-painted tip, as usual. The headstamp (of the WW2 British production stuff) was the year and W-something (Another letter, I can't remember exactly which one, and my ammo's not on hand to look at. If Ronin308 reads this, he could take a look at it and tell us), and had a green-colored primer sealer.