Another possibility - though it's never, never happened to me personally - is a tilted rifle.
I've seen some other guy line his horizontal cross-hair up parallel with the top of the target frame, which turned out not to be fully seated in the holes in the ground. Threw a very consistent group neatly off to the right, it did.
Jaywalker
I've seen some other guy line his horizontal cross-hair up parallel with the top of the target frame, which turned out not to be fully seated in the holes in the ground. Threw a very consistent group neatly off to the right, it did.
Jaywalker
