Isn’t hornady the only brand of factory loaded 375 Ruger ammo? I’d take the lighter option IE 270g rather than 300g.
If you could find something loaded with a 260g accubond or a 250g ttsx, that’s what I’d take. I’ve killed multiple bulls wit those bullets but out of my 375HH, I’d use either of those.
I’m not all that familiar with factory 375r options but I’d go for a 270g class bulllet, no reason for a 300g but it would work just fine if that’s what you end up with.
In reality, anything out of a 375 is more than adequate for any moose out there, even an 80” one is answering around out there unaware that humans exist. Hell I have a feeling that I was the first human any of the moose I’ve killed ever saw.