Winchester moly-coated 64-grain PowerPointPlus, but that does you no good in choosing an ammo because it was discontinued several years ago.
I'm down to probably 275-300 rounds of it now. Been experimenting with the Federal Fusion MSR and PRVI 75 BTHP, and so far am very favorably impressed with both.
That said, there are a lot of good defensive-use choices out there in the AR calibers. Especially if you avoid the varmint bullets, and match the bullet weight to your gun (which isn't as big a problem now as it used to be), and see what your gun likes, there are many good options.