Traditionally, a 6x is about right for a Hornet. Higher powers can certainly be used, but 6x gives enough magnification for small targets at not too far range, without the smaller field of view and magnified wobbles that you get from high power varmint scopes.
This dates from the era when fixed power scopes still ruled the roost, back when vairables were large, heavy, and prone to change point of impact when you changed powers.
Today, anything under 9x, or 3-9x variable will do fine, provided it is small enough to not "unbalance" the rifle.
My Ruger No.3 currently has a huge old 3-9x on it, (just for testing purposes), and while it works, that scope seems like it is half the size of the rifle. I will be mounting a smaller scope on it for field work.
My .22 Hornet Contender barrel has a low power (<2.5x, I can't remembe right now, and am not going to go look,
) and it works pretty well, although spotting your misses at 100+yds is kind of tough.