I believe that Swedes hunt Elg, which are their version of Moose, with 6.5x55, so, I reckon that would suffice, here, on this side of The Pond. It could be the one cartridge to do it all. The OP did not mention bear or bison, or 1000-yard competition shooting. I seem to remember noticing that 6.5x55 was one of the very few rifle cartridges available, this past week, at a leading on-line ammo seller.
6.5 Creedmoor is trendy, it so it might be easier for me to find a left-hand-action turn-bolt rifle that chambers it, and, so, I might as well add it to my list. Who knows when I could expect to see the ammo available, from a widely-respected seller?
If I had to buy, today, well, 6.5x55 ammo from Midway USA, and a Ruger No. 1 rifle, through Gunbroker. There are two versions of the Ruger No. 1 listed, that chamber the 6.5x55, the 1-A Sporter, and the RSI. I reckon that these two would do, nicely. There.
Who needs turn-bolts, anyway? This was a quick thought exercise.
1. Ruger No. 1, version 1-A Sporter, 6.5x55.
2. Ruger No.1, version RSI, 6.5x55.
Varmints to moose. Where I live, varmints are close-range. I am not going to travel to shoot varmints. No bears, buffalo, bison, or humans. No 1000-yard targets. Why complicate things?