I wouldn't worry about it too much. Alot of factory rifles have throats cut way too deep for a bullet to be seated anywhere near the rifling and still fit in the magazine. Even if the throat is short enough, it might not have been cut perfectly square so seating up the rifling can hurt accuracy. I wouldn't go any closer than .020"- it will more likely cause higher pressures and poorer accuracy- unless your rifle is a match rifle and you are shooting match grade bullets that you've carefully measured your oal from a reference point on the bullets ogive.