It does not have a parent case, it was created by Hornady.
It is the baby of across-the-course shooters who are competing against .308s and .300 Win Mags. This cartridge fits in a short action (or AR-10 action) but has a better trajectory and less wind-drift than a .300 Win Mag.
Hornady sells ammo. Not sure who else. If you're really using the cartridge to its capacity (600+ yards), you'll want to handload. It's similar-ish to the .260 Remington.