assuming a good release, good arrow flight is a combination of stiffness, length, point weight. Feathers can correct bad flight, but it's better to get it flying straight by adjusting one (or more) of the 3 factors above. If your stone point is lighter than your normal points that may be causing the issue. Can you tell if the arrow is flying with the feathers to the right or left? Did you use feathers from the same wing? Are you right handed?