i am a two rifle owner, leaving out a .22lr. One of them is a sporter, made in a mauser 98 action, cal 7x57 mauser and equiped with a 4X fixed scope. I have some experience with 30.06s, .308s, 6.5x54s and 243.s. This last seems too light for my tastes. I have not found any hunting situation for which the 7x57 would be noticeably surpassed by any of these other cartriges, and the beasts I have put down that were too big for it ( nevertheless, they fell dead...) were too big too for the 06. Unless I was moving to Africa ( a dream...) I would not want another rifle, and even if my dream came true, the little 7 would certainly be the most used one, next to the 9.3x64 that I would buy. BTW, I only use 175 grain psp or 162 solid bullets in it.
Other rifle I have: a rossi lever action in .357 mag. Every senior brazilian have a sweet spot in his heart for winchesters mod 1892 in 44.40, for this is the rifle that won our west, and east, and north, and south. I find the little rossi, a faithful copy of the 92, more effective in medium game at distances 50 to 80 yds than the 44.40. More accurate too. Many times, when going hunting freal goats in dense brush, I helitate a lot between these good rifles