Most accurate rifle? Well that's going to depend on each individual person. I've been shooting and loading for more than 40 yrs and it's been my experience that if you're willing to spend the time, you can make any of them shoot, of course considering that I rifle hasn't been damaged or misused. Some may take more time to get there, different loads, glass bedding ect. But I've seen some that you could hit on a good load right out of the box, and some you had to work at. I had a rem 788 in a 243 cal that took quite a bit of time to get there, and I have a Ruger no-1 25-06 that I hit right out the box.
These were the the extremes, and the rest have fell in the middle. Both of these rifles would shoot a 3-shot group at a 100 yds that you could cover with a dime.
The big skinny is how hard are you willing to go and what's accurate to you?