Re: bilding a 260
The barrel is the heart. For LR, longer, heavier bullets are more appropriate, so a rifling twist as noted above is a really good idea. I do my shooting prone, and not far from the car, so I like a longer, heavier barrel. Mine are Lothar-Walther, 28" 1:8" Stainless, BR grade, factory threaded for user installation on the Savage action, and mine are factory SAAMI .260 Rem chambered. $308 plus shipping.
My rifles are built on Savage 10FP actions. They have McaMillan A-series Tactical stocks, but the recent additon of the Savage Accue-Stock feature to the production products is a genuine improvement, as long as you like a stock with hunting lines. The newer single stack 4-round detachable magazines are a good feature too, and Sharpshooter supply sells an upgrade kit that boosts them to 10 (9?) round capacity. The Accue-Trigger remains the best factory trigger in existence, IMHO.
Things like stock packs, Limbsaver Pads, and Cheek-ease foam stick-ons can go some way toward making a more mundane stock fit well enough until a more specialized impement can be acquired. Optics need be clear, bright, and reliably adjustable. There are several levels of price range, with appropriate reliability, etc., factors.
Avoid the cheap bargan scopes, although some are outstanding bargains, start with a decent midrange, like Weaver or Burris, and upgrade from there is your budget and actual needs dictate. Optical mounts need to be relatively rugged and provide a slope value which is compatible with scope adjustability range and shooting distance requirements.
Greg