I don't shoot informal targets at 600 yards, but I rebarreled a Remington 700 SPS from 270 to 6.5x55 last year. It is a simple job, just install a new barrel. If you're going to shoot iron sights, you'll probably want a stock that puts your eye in the right alignment for irons, probably lower then for optics.
Extending the conversation:
If the only part from this rifle that you're going to use is the action, I think that you'd have a better rifle starting with a custom action, like a Stiller Predator, then having your current action reworked.
www.viperactions.comWarning, serious target shooting can nickel and dime you into the poor-house.
Jeff
