So SAAMI have recently (last year) ticked off a new 45 rimmed chambering (maybe its been around for a while as a wildcat??)
The pretty awesome sounding '457 Wild West Guns' aka 457WWG...
Sound interesting, but....
Its basically the 45 Govt. with an extra 1 tenth of an inch case length. Thats it. Is it worth it? or is it a matter of getting a round officially in your chosen name perhaps, given that it would offer what, a 'few' fps more potential than the 45-70, its less than the 45-90, a lot less than the 450Nitro??
Pro: you could easily ream your 45 single or double rifle
Con: you'll need new brass, reloading bits and load development...