Well, you are absolutely right.
It's just that I will be doing all the reloading for my Dad's .260 Savage (the most his shoulder injury allows) and I'll soon be getting in dies/bullets for that. Thus I will have these components on hand anyway and could test the same loads in my own rifle when he tries them in his.
It's silly logic I guess. I just have so many dies in so many calibers - for guns I don't even own anymore - that I almost hate to buy any more if I can avoid it. Unrealistic I suppose, and honestly they aren't that expensive. Brass, on the other hand, now that is hard to come by right now. I already have a BUNCH of new, unused .243 brass I'm gonna neck up to .260 for him.
The 7mm-08 rifles are WAY easier to find... and I have been wanting a .35 rifle of some kind for experimentation...