Group size will remain constant. POI may differ between shooters. A friend and I have been shooting together for more than 20 years, when we switch guns, his shoot low for me, mine shoot high for him. It's just how it is, we sight in for ourselves, when others pick up a gun it'll be close but not guaranteed to be on. Eye relief, size of head and neck are different so cheek weld will differ. This has been the case for all guns, wether air powered or not. But should be very close. Best thing to do is have them sight it in to ensure it's on.