I can't swear by it, but I think my Hornet is 1 in 9 also.
I tried Prvi, Remington, S&B, but Winchester 46gr HP basically gave 1 MOA out of the box...was really obvious too compared with the others. However, it was the last box to be fired on the first outing, so the Prvi, S&B and Remington may have been barrel break-in. Plenty of other Hornet folks also praise the Winchester 46gr HPs.
For reloading, it sure does like the heavier V-Max, but Sierra BlitzKing worked fine too, either one with a full case of L'il Gun.
I think K-Hornet or Ackley Hornet is a great idea just for case life, and the 221 Fireball is an obvious rechamber too, some here have done those and it is on my short list for a second barrel or rifle after I do the K-Hornet or Ackley Hornet.