keep in mind i've seen some rifles shoot like yours(great at 100 and bad past) and i've also seen some do the opposite(1-1/2 or so at 100 then 1-5/8 at 250). i would suggest you mess with your load a little more and see what happens. also, are you shooting at 100yds in the morning and then further later in the day? fatigue could be setting in both physically and mentally. i've seen this happen many times during matches.