ballistics

Don’t know much about ballistics. I just know that where ever my gun is shooting, at 100 yards I only make one hole. I bought ammo for my 270, (130 grain premium Federals) for the first time in 5 years. Went to shoot yesterday. Gun was right on, 1 1/2″ high at 100 yards and centered with the old ammo. The new ammo had just as good of a pattern but it was 2 inches to the right. No wind where I was shooting. I can understand elevation changes with different batches of ammo but what is it with the off to the right stuff. I redialed for 0 and used the rest of the old ammo to shoot a couple of cans, tin cans, not ducks.