Don't waste your time with 168smk's past about 600 yards. You will leave the range frustrated and will have sent most of those smks into dirt. There is Toms if info and data out there that shows that the 168 has a unique case of dynamic instability as and becomes unpredictable as it approaches transonic velocity. After that, all bets are off. Factory 168 loads will likey go subsonic between 780-850 yards ot of a 22"barrel.
Bottom line, limit yourself to 600 ish yards with that ammo unless you like wasting money.
My pet load uses the lapua 155 Scenars. So long as the wind isn't blowing wildly i have better success with it at longer ranges.
My second choice is the 175 smk.