Look at a yard stick taped vertically to you target at 100yds. Lock the gun in sand bags, adjust as you watch the movement up along the yard stick. In four clicks your crosshairs should have moved about one inch if they're 1/4moa clicks. Verify by moving 40 clicks, it should be around ten inches off now. If you set the yard stick out at 25yds it would be 2.5". If it's not, you have problems. \
Also check the far edges of the scopes adjustment, it should be repeatable and consistant throughout the full range of adjustment.
Check windage the same way.
The gun MUST NOT MOVE AT ALL.