i am shooting a 308win. with a handloaded 168 gr. hornady match bullet the load chronagraphs ave. 2700 fps. i am sighted in 2" high at 100 yards. using a ballistic calculator on the internet called big game info. i got my come-ups called for 23 clicks at 400 yds. my group at that distance was eight inches low. this is my first attemp at using come-ups and i am at a lose. help