The easiest, by far, is the 25 Niedner.
It takes 270 brass (resized and trimmed) and 257 bullets. You use the exact same load data as the 25-06.
I've got one. Nevermind the '25-06' marked on the barrel. I tell everyone it's a 25 Niedner, and everyone thinks it's cool.
Another one of my favorites, even easier to load for, is the 7.62X63. That's my favorite for deer. Everyone in camp shoots one.
