Found a very informative topic about the best zero ranges PBR of .177 = 8.8 to 35 meters (9.7 to 38.3 yards) - PBR = point blank range. .22 cal PBR = 6.3 to 28.5 meters (6.9 to 31.1 yards). Basics are that if you were to zero to say 30 meters in .22 with a sub 12 ft/lb "ish" rifle you would run the risk of being out of your kill zone from 11.5 meters to 25.5 meters due to the pellets parabolic trajectory leaving the 2.5 cm ( 1 inch) kill zone.