Why by the .454 then
If you are going to shoot .45 lc, buy a .45 lc. I have an assortment of the small calibers, but I wanted a big boy, and I shoot a big boy with big boy ammo.
If you can't take the heat stay out of the kitchen!!!
I was thinkinking cost (for the .45s) as well as intensity of practice. Shoot 20 full power, or 40 lower powered rounds. Whatever works for you. Again, if you reload, its a non-issue. Howeverl, when I was practising for duck season I still shot my skeet rounds with 2 3/4 inch low brass #8s, not three inch #2s. YMMV.

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FQ13