7x57
I think a 7X57 will do the job on any big game animal in North America.
The only problem with some factory 7X57, some manufacturers down loaded because of the older guns. I wouldn't want to put a high pressure round in my Remington Rolling block, or my Spanish 95's. I wouldn't think twice about putting a good load through my 1908 Brazilian. I had a problem with rounds in my custom built 7mm, there was carbon around the neck of the cases after firing it scared the crap out of me. A custom 7X57 and when that started I thought, "dam I have a dud". I talked to my gunsmith and he asked if the rounds I was using were European manufactured, and pointed out there wasn't enough pressure created to seal around the neck when I fired the gun. I tried Remington and Winchester ammo and no problems. I just got a Remington 700 BDL rebarreled from 6mm to 7-08 and I can't wait to shoot it. I just like 7mm Mauser and 7-08 for hunting. I have a new stainless 24" 7-08 barrel sitting on my shelf ready to install on a future Remington project.
I would reload my ammo for the hunt if I were you, but there are enough experienced people here to correct me if I am wrong.
I am thinking about reloading my ammo but I never got around to it.
I probably had enough equipment to reload 20,000 rounds of 223, 308, 7mm, 30-30, 270, 38, 45 ACP, and you name it I probably had it. I did have powder, but I just sold it off with 30,000 primers because I have never loaded a round in my life. I will just get someone to teach me to reload my ammo and go from there.
Good Hunting
Albayo