I don't load for the 17 Hornet, but I do load for the 17-223.
The Hornet is a better option IMHO, simply because of fouling issues. Velocities are very good for most of the ranges the 17 cal bullets will be used by the average shooter.
Bullets are usually available from at least three of our "banner" advertisers, such as Reliable, SFRC and Intersurplus. Likely others as well.
You will want to stock up on "Lil Gun" powder for best and most consistent velocities.
Small rifle primers, either standard or magnum work just fine with Lil Gun, which is still readily available, check out Budget at the top of the page.
You will find the 17 cal bullets to be extremely accurate, until the bore becomes fouled with jacket metal.
In my 17-223, I'm lucky to get 20 shots before I have to clean the bore or the groups open up very quickly afterwards.
I've tried everything from moly coating to powder coating and even lubing the tips of the bullets, I still get extreme fouling issues at the best accuracy load velocities.
The only thing which reduces the fouling is to reduce the powder charge, which your 17 Hornet does perfectly.
I've spoken to a friend who just had to have a 17 K Hornet. He did get a bit more velocity, but he also started to get more jacket fouling.
There seems to be a fine velocity line where the fouling starts to become excessive faster.
I've never looked into it but maybe the jacket metallurgy calls for softer materials? Or maybe the forces generated on normal metallurgical materials are greater because of the reduced diameter and bearing surface proportions to energy?