It's not difficult to use a little bubble level kit.
Stabilize the rifle and level the barrel, front to back, left to right.
Attach the rings to the scope somewhat loosely, then mount to the rifle.
** If the reticule is not canted inside the scope, the adjustment knobs are at right angles.
Place the level on the knob on top of the scope, keeping it level while gently tightening the mounting screws.
** Don't overtighten the rings, as you can dent the tube.
Make sure all screws are tight enough to prevent movement/loosening when shooting.
If the reticle looks canted, then level the rifle and find a vertical line that's perpendicular to the floor. Maybe use a window, a door frame, etc. Twist the scope to align the reticle with the vertical line you chose.
Keep checking the rifle as you go to make sure you didn't move it out of horizontal alignment.
I've tried this many times, and it gets easier and quicker each time as you learn what to do.
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