As has been said here earlier, there is no perfect rifle for all situations. I have killed moose with my .300 win mag, .35 whelen, 7mm rem magnum, 30-06, and lately my Brno .375 H & H magnum. All of these calibers are effective, but you definitely want good bullet construction with the .300 win mag and 7mm. Worst bullet performance I have seen is with factory ammo with the .300 win mag. Most spectacular kill was a large bull moose with the 7mm with 175 grain nosler partition handloads. The moose literally fell over backwards off the river bank and onto the shore with a chest shot. If I go moose hunting now though I will use my .375 with 270 grain Hornady handloads. This rifle is capable of a zero hold shot on any moose up to 300 yards and it is very comforting to know that if you hit the animal well in the chest, it is sure to not go too much further. The rifle is a bit heavy tough and if I were going for sheep, I would probably take my ruger compact in .308, just because it is good for 200 yards at least and is short and light and in a pinch could be used for bear defence.
Norm