OK, no one else is piping up, so I will start with an opinion, and I am sure someone else will come and disagree. That way the waters will stay muddy.
Given what you want to shoot at, and what sounds like a possibility of hunting deer. I think you should go ahead and use the Nikon that you have, and mount it to a Tikka T-3 Varmint in a 260Rem, or a 7mm-08. These will be pretty light on the recoil, able to reach fairly far, easily re-loadable, and still have enough to harvest a deer easily.
Now stand back, lightning may strike.
Good luck with what you choose, and have fun. If you decide for sure what you want, check out usagunclub.com. It'll save you a fair amount of $$.