Re: tell me about 30-338
Use Imperial Wax, and be careful to straighten all the necks with a 338 expander ball first, and they should form just fine. My 308-264 needed 2 steps but just barely. I do 416's, 560 in the body down to 340 in 4 very easy steps.
There's about 1760 yards in a mile. If you build one that won't shoot that far, I'd throw it away and start over!
Seriously, if you do a 32 or 34" barrel it'll have no problem with that range. At least not as much problem as you're gonna have with the cost of practice to get good enough with it.
If you have something that you disassemble and reassemble enough times, sooner or later, you'll have two!