I would not call myself experienced in shooting at all butI own a few rifles, mostly Remingtons, and get decent accuracy out of the box with factory ammo (1 to 1.5 moa). I recently bought a Cooper in 338-06. I intend to reload for it and just bought equipment and am learning how to reload. I got three boxes of ammo so I could shoot the gun right away. 180 accubond, 210 partiions and 225 accubond all by Nosler Custom. I have not been able to shoot better than 3 to 5 inch groups off a solid rest at 100yds with this ammo. After the first 10 or 15 shots I left the range and re-mounted the scope (tally rings Leup vx3 4.5-14) because I could not believe how wide the groups were. After re-mounting nothing changed. I called Cooper and they said it was the loads. Ok, I got their load data and I will reload their exact load for 338-06. (Sierra 215 GK, IMR 4064 49grs, COAL 3.286) My question is can reloading really make this much difference. I would expect this rifle to shoot sub moa easily. I can see getting any of my other rifles to sub moa by reloading but can I expect to get 3 to 5 inch groups down to sub moa by reloading? Any comment would be appreciated.