How to mount a rifle scope: step by step
Quick answer: mounting a scope well comes down to five things: pick rings of the right height and diameter, level the rifle then level the reticle to it, set eye relief by shouldering the rifle at maximum magnification, torque the ring screws to the manufacturer’s spec with an inch-pound wrench, and bore sight before you head to the range. Rushing the leveling or guessing at torque is where most mounting problems start.
Safety first. Always confirm the firearm is unloaded before you start and keep it pointed in a safe direction. This is a general guide, not professional or safety advice; follow the exact instructions and torque values from your scope, ring and firearm manufacturers.
What you need
- Rings or a one-piece mount in the correct tube diameter (1 inch, 30mm or 34mm) and a height that clears the objective bell.
- An inch-pound torque wrench with the right bits (guessing by feel is the top cause of damage or slippage).
- A small bubble level (or two), plus a scope-leveling tool if you have one.
- Quality thread locker if the manufacturer calls for it on base screws.
Step by step
- Mount the base and bottom rings. Fit the base or bottom ring halves to the receiver rail and torque the base screws to spec. Confirm the rings are the right diameter and give enough objective clearance.
- Level the rifle. Clamp or steady the rifle and use a level on a flat reference (the scope base or action rail) so the rifle itself is dead level. Everything else references this.
- Set the scope in the rings and set eye relief. Lay the scope in, snug the caps just enough to slide it, set magnification to maximum, shoulder the rifle naturally, and move the scope until you see a full, shadow-free image. That position is your eye relief.
- Level the reticle to the rifle. With the rifle still level, rotate the scope until the vertical crosshair is truly vertical (a level on the turret cap or elevation flat helps). A canted reticle sends shots sideways as you dial for distance.
- Torque the ring caps evenly. Tighten in small alternating passes, side to side, to the manufacturer’s inch-pound spec so the gaps stay even. Re-check the reticle stayed level as you torque.
- Bore sight. Bore sight optically or with a laser so your first rounds land on paper, then confirm eye relief and reticle level one last time.
- Zero at the range. Finish with live fire. See how to sight in a rifle scope.
Common mistakes to avoid
- Guessing torque by feel: crushed tubes and slipping scopes both trace back to this. Use the wrench.
- Setting eye relief at low power: set it at max magnification so you keep a full image at every zoom.
- Skipping the reticle level: a small cant is invisible up close but throws shots off at distance.
- Rings too low for the objective: the bell should clear the barrel and any iron sights.
FAQ
How tight should rifle scope ring screws be?
Torque to the ring and base manufacturer’s published specs using an inch-pound torque wrench; there is no universal number. Ring cap screws are commonly in the 15-18 in-lb range and base screws higher, but always follow the exact figures for your hardware. Over-tightening can crush the scope tube or strip screws, so a torque wrench beats guessing by feel.
How do I set eye relief when mounting a scope?
Before final tightening, shoulder the rifle in your normal shooting position with the magnification set to maximum, then slide the scope forward or back in the rings until you see a full, shadow-free image. Lock it there. Setting eye relief at max magnification ensures you keep a full picture at every power, and it keeps the ocular a safe distance from your brow under recoil.
Do I need to level a rifle scope reticle?
Yes. A canted (tilted) reticle throws your shots sideways as you dial elevation for distance, and the error grows with range. Level the rifle first, then level the reticle to the rifle using a level on the turret cap or elevation flat, so your vertical crosshair matches gravity when the rifle is upright.
Is bore sighting the same as sighting in?
No. Bore sighting roughly aligns the scope with the barrel so your first live rounds land on paper, saving ammo. Sighting in (zeroing) is the live-fire process of adjusting the scope so point of aim matches point of impact at your chosen distance. Bore sight first, then zero at the range; see our how to sight in a rifle scope guide.
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