ok. well i sighted my Browning a-bolt with hornady 160 grain bullets and they were grouping great at 100 yds (.25 inch 3 shot groups). i decided to change to barnes MRX 140 grain. loaded them with IMR powder @ 60 grains. i went out to the range and can not get the barnes to shoot a good group at all (3 inch groups @ 100 yds). is it because of the 140 grains? should i be able to group better with 160 grain MRX? have anyone tried the .284 MRX with success. state powder, grains, etc. thank you all.