I would guess that you mean the current 308 1000 yrd "sniper" rifle ?
My dad built one in '74 , a 700 BDL bull bbl target crown .980 at the muzzle 4-12X40 w/range finder. The only differances in his and theirs is the optic brand ,stock, and finish, his is a 25-06' not 308 .The use of the long action for a short action cartrige seems awaste to me but a nessasary step for crud displacement . To day you'll be in it about 15-2000 ,6-700 if you have an action and optics to start with.