The one gun for mostly big game would have to be a Sako AV in 30-06. While I've found the 06 to be a bit much for deer it's suitable for moose and caribou. Above that the 300 WSM offers a bit more for moose and elk.
Mine was found. A custom Remington 700 in 358 Norma Magnum
I also just found a crazy nice Weatherby lazermark in 270bee if i was going to hunt with only one gun it would be this one. It was hard to find with a dark stock in basically brand new condition. I am putting a 6-20x40 leupold in gloss on it. One day after load development i will send it to korth for a german#4 and a cds dial
Been kind-of lusting for a full stock Martini and Hagn rifle
In the more reasonable scheme of thing... An older Steyr would be nice
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Decent
Seven point six two by thirty nine full metal jacket
The one you've got that works that you have the most success with
11,000 views about a fantasy holy grail firearm and 5500 views for wolverine in the senate fighting for you to keep your guns . ???