While it's ALWAYS best to shoot at the range you want to see where it'll impact,it is possible to shoot at 25 yards then know about where your bullets will hit. To do this you have to figure in scope height above bore,and trajectory. Usually when I start at 25 yards,before going back to 100 yards with your cartridge,I'll adjust scope to poi at about 1 inch low at 25,then move to 100 and it SHOULD be pretty doggone close,BUT like he said,the only way you'll know for SURE is to shoot from 100 yards.