I think you can't go wrong with a Ruger 10/22. Alot of after market parts to customize. Heres a picture of my squirrel sniper gun. It's a Ruger 10/22 with some after market parts.

The reciever and the barrel is the only stock parts. Has a Simmon .22mag scope, muzzlebrake, Dragunov sniper stock, Volquartsen hammer and trigger andsprings(crisps 2 3/4 lbs trigger),customize magazine release and bolt handle.This shoots 1" groups at 50yrds.

http://photobucket.com/albums/a121/lunker651/Guns%20N%20Ammos/?action=view&current=1fa62b1d.jpg