I've loaded for two, one was an "Alpine", a Parker Hale take-off back in the mid 70's, as well as a Model 70 in early 2000. The first had trouble, difficulty with it's chamber or barrel as no factory ammo could be used. Being a handloader, I helped the owner with handloads, but found nothing in the books, not even starting loads were suitable, and ended up with a safe maximum load using IMR4895 and IMR4064, with 3gr. less than the listed starting loads. The bore, groove diameter and chamber all mic'd out correctly - couldn't figure it out- very much like your first Ruger.

The one I owned in early 2000, a used gun built in the 1980's, had a 24" bl. but was a slow barrel. At maximum loads, the best it would do is 3,350fps with a 120 gr. "XLC", and about 2,860fps with 140's.

I built a .260 CLC (necked down 7x57 with the same front end profile as a .260 Rem) which had a 60gr. capacity. With top end loads using RE#19, it ran 3,308fps with the 120 XLC, only 42fps less than my 'high falutin' .264 WM in Mag, but the .260 CLC did it with only 52gr. of powder, compared to the .264's requisite 85gr. of powder. 33gr. less powder for the .260 CLC and only 42fps slower. With 140's the CLS was good for 3,100fps, a full 260fps faster than my .264. I wasn't happey with the .264.

It's no wonder I rebarreled it, threw away it's tube and chambeered the new one for the .458 Alaskan. It's 350gr. bullets were only 200fps slower than my .264 Win Mag would do with a 160 - I found that interesting.

BTW - I can't think of a better use of a rapid expanding 120 or 100gr. than from the .264, piling into a wolf - just about anywhere will do.