I would buy the AO, even if your 7MM will be used only for long range shots, beacuse one day you might sell the 7mm but keep the scope for something else like a 22 target/varmint rifle or a 222, 223, 22-250, 308, etc. The option of an AO is needed for clear focus when using a rifle for a variety of ranges. Even at a close range you can keep it on 12x and use the AO to focus. It's a very nice feature if you are going for head shots on small game and varmints, or need to pick a chest shot between branches and cover on larger game.