About a month ago my granddad finally got his old 300 Weatherby back from his cabin in Colorado. This particular Weatherby is a German made Mark V Deluxe topped with a Swarovski 6-18x50mm scope. He's had this rifle for about 50 years and hunted all over the continent with it, as well as in Africa.

During his last hunt on Santa Rosa island a few years back, he discovered he couldn't sight it in. For whatever reason, it wouldn't shoot straight. He couldn't get it to group, and niether could anyone else in his group. Frustrated, he kept it at home from then on.

He let me borrow it to see if I could figure out what's wrong. Long story short, it was shooting 6 or 7 inches to the left and 4 inches low at only 25 yards. I tried to adjust the scope, but I maxed out the adjustments and it was still shooting low and to the left. At 50 yards, I discovered something else: the bullet holes were oblong, not circular. However, using newer ammunition fixed this issue.

I took the rifle to a gunsmith, who believed it was an issue with the scope. He fixed something with the scope mount and boresighted it for me. Today I shot it again at 25 yards, and once again it's shooting over 6 inches to the left at that distance.

I have no idea what to do now. Any idea as to what's causing this issue?