I've been shooting mostly Hornady factory but also am loading 350 and 400 gr Swift A-Frames to the same velocity.
The top barrel of my Zoli tends to shoot 5 to 7 inches high with Hornady Factory ammo ( it is an early gun and was regulated with Kynoch) Since both barrels are perfectly in line I simply started playing around and found that with the bottom barrel printing on at 100 the top barrel was hitting on at 300.
Zoli has offerd to re-regulate the rifle with Hornady ammo but I am beginning to get used to the idea of knowing exactly where I can hit and at rock throwing distance where the double really earns it's keep both barrels are still minute of a bear.