When I start a new scope, I set a target at 25yds and zero the scope to dead center at 25yds. Then I move the target to 100yds and fire one shot. Should be fairly close to where you want. Next, get the rifle held solid and put the cross wires on the 100yd bullet hole. Hold it there and adjust the cross wires to where you want poi to be. Then just fine tune.

Shooting at 50yds serves no purpose. 25yd zero will put about any cartridge on the target at 100yds.