Midway through season last year I purchased a box of 155gr BXC ammo for my 300. It shot the exact hole my Rem PSP's did at 100 yds, so I carried on. Didn't take a shot over 50 yds the rest of the season and was very impressed with the performance of the round. I missed a deer this past weekend at 300yds. Shooting off sandbags and I was on him. I've killed deer, coyotes and even crows at the same crossing so I know it is a shot I can make. My son even killed one there when he was 13 with this gun. I went home pretty dejected and went to a range where I could stretch it out a little. At 200 yds best I could do was about an 8" group. I've made sure all my scope mount and base screws are tight and barrel was cleaned. All I can figure is I need to do some dialing on the BOSS. I called Browning customer service yesterday and a guy told me they did not have any data on BOSS settings for the new ammo. I was hoping maybe someone here knew a good starting point. Thanks!