I have every scoped bolt action unlocked except the Garand, I had the Garand unlocked at 3rd prestige, and I'm now 10th prestige 65. Don't bother, I'm serious, the Garand is shit. I used to shoot people in the chest and they don't even have Juggernaut, and it still doesn't do jack shit.
I am currently using the Kar98k, which is, in my opinion, the best sniper available. But until 10th prestige stick to Springfield cause unlocking scopes is too much work. The Springfield is a great sniper, and the Nagant just doesn't work for me, it has lots of recoil. The PTRS-41 is also an option, it can knock out those juggernauts in one hit, but it's unlocked way too late.
In short, stick with the Springfield, or use a Kar98k. I didn't try the Arisaka alot with a scope but from what I've seen it kills everybody in one hit, I only killed about 20 people with it though. I don't use it alot.

EDIT: ignore VIOLENT MAK, the Garand has more recoil than any bolt action. That shit goes up with every single hit.