i startred a new lot of matchkings in my 6.5-284 and groups have gone to hell.i have measured the new seating depth several times to verify that im where i should be,i have tried different seating depths and the best i can get is about 1/2-3/4 moa with the rifle shooting two groups -say 2 in hole 3 in the other, nothing on the rifle has changed that i know of -everything is tight,and where it should be[i have checked it over several times].i have even tried working with the powder charges,the sd's are very low -under 10 for the charges,but the accuracy is just not there.basically im stumped this was 1/4 min. rifle with only 350 rds down the tubei shoot it nice and slow to let the barrel cool and im very careful when cleaning etc.....any and suggestions are appreciated-tia-dave