Getting your rifle and scope to work together perfectly starts with a proper installation. Learning how to mount a rifle scope correctly is the most important step for accuracy. A poorly mounted scope, no matter how expensive, will never hold zero or shoot consistently. This guide will walk you through the entire process with clear, step-by-step instructions, so you can do it yourself with confidence.
You’ll need a few basic tools before you start. Gather a set of gunsmithing screwdrivers or bits that fit your scope base and ring screws perfectly—using the wrong size can strip the heads. You’ll also need a torque wrench (inch-pounds, not foot-pounds) for proper tightening, a leveling kit or a set of levels, and some thread-locking compound. Having everything ready makes the job much smoother.
How to Mount a Rifle Scope
The core process involves attaching a base to your rifle, securing rings to that base, leveling the scope, and tightening everything to precise specifications. Rushing or guessing at any step will cause problems down the line. Let’s break it down into managable stages.
Gather Your Equipment and Prepare the Rifle
First, ensure your rifle is completely unloaded. Remove the bolt or open the action so you can see clearly through the barrel from the breech end. This is a critical safety step. Then, give all the components a quick clean. Wipe off any factory oil from the rifle’s mounting points, the base, and the inside of the scope rings. Any debris or grease here can affect alignment.
Step 1: Install the Scope Base
Most modern rifles have pre-drilled and tapped holes for a base. Here’s what to do:
* Apply a small drop of thread-locking compound to the base screws.
* Carefully align the base with the holes on the receiver. Some bases are directional.
* Finger-tighten the screws initially, then use your torque wrench to secure them. A typical specification is 25-30 in-lbs, but always check your base’s manual.
* Double-check that the base is secure and doesn’t wobble.
Step 2: Attach the Bottom Scope Rings
Now, attach the bottom halves of your scope rings to the base. If you’re using a one-piece base, the rings might integral or separate.
* Again, use a tiny bit of thread locker on the ring-to-base screws.
* Place the rings in their intended positions on the base, leaving enough room for the scope tube.
* Tighten them down to the manufacturer’s recommended torque, usually 15-20 in-lbs. Don’t fully tighten just yet, as you might need to adjust them slightly for eye relief later.
Step 3: Level the Rifle and Set Eye Relief
This is the most crucial step for a correct setup. Place the rifle in a solid, stationary vise using padded jaws. If you don’t have a vise, use sandbags to immobilize it as much as possible.
* Place a small level on a flat part of the rifle, like the receiver flat or the base itself. Get the rifle perfectly level in the vise.
* Now, set your scope in the bottom ring halves. Before tightening, slide the scope forward and backward while shouldering the rifle. Find where you get a full, clear field of view without moving your head—this is your proper eye relief. Mark this position lightly with a pencil.
Step 4: Level the Scope and Install Top Rings
With the rifle level and scope positioned for eye relief, it’s time to level the scope itself.
* Place a level across the flat top of the elevation adjustment turret (the one on top). This surface is machined flat and is reliable for leveling.
* Gently rotate the scope in the rings until the scope’s level matches the rifle’s level. This ensures your crosshairs are plumb.
* Once level, carefully place the top ring halves on. Start threading the screws by hand to ensure they aren’t cross-threaded.
Step 5: The Final Tightening Sequence
Never tighten screws all at once. You must follow a specific sequence to avoid putting uneven pressure on the scope tube, which can cause it to bend or not hold zero.
1. Lightly snug the front ring screws (top halves) alternately, just enough to hold the scope from rotating.
2. Do the same for the rear ring screws.
3. Now, using your torque wrench, final-tighten the screws in a criss-cross pattern on each ring. A common torque spec for ring screws is 15-18 in-lbs. Over-tightening is a common mistake that can crush a scope tube.
4. Finally, re-check all levels one last time before moving the rifle.
Step 6: Bore Sighting and Final Zeroing
Bore sighting gets you on paper, saving ammo. You can use a laser bore sighter or do it manually:
* Secure the rifle in a steady rest.
* Remove the bolt and look directly down the bore. Center a target object about 25 yards away in the barrel.
* Without moving the rifle, look through the scope. Adjust the windage and elevation turrets until the crosshairs are centered on that same object.
* Your scope is now roughly bore-sighted. The final step is to take it to the range and zero it with live fire at your desired distance, making final adjustments.
Common Mistakes to Avoid
* Overtightening Screws: This is the number one error. Always use a torque wrench.
* Ignoring Eye Relief: Too far forward or back leads to poor sight picture and even scope eye from recoil.
* Forgetting to Level: A canted scope causes accuracy problems that get worse with distance.
* Using Poor Quality Mounts: Don’t trust a expensive scope to cheap rings and bases. They are the critical link.
* Skipping Thread Locker: Vibration from shooting can and will loosen screws over time.
Choosing the Right Mounting System
Not all mounts are created equal. Your choice depends on your rifle and use.
* Picatinny Rail: A one-piece rail that offers maximum flexibility for ring placement. Very strong and popular for tactical and precision rifles.
* Weaver-Style Base: Similar to Picatinny but with slightly different slot dimensions. Accessories are often cross-compatible, but its not a guarantee.
* Dovetail Mounts: Common on .22 rifles and airguns, where rings clamp directly into a grooved receiver.
* Dedicated Bases: Some rifles, like certain shotguns or older models, use proprietary bases that accept specific ring styles.
Your scope rings must match your base type. Also consider ring height—you need enough clearance for the objective bell to clear the barrel, but you want the scope as low as comfortable for a solid cheek weld.
FAQ Section
How tight should scope rings be?
Always refer to your ring manufacturer’s instructions. As a general rule, ring cap screws are typically torqued to 15-18 inch-pounds. Base screws are often tighter, around 25-35 in-lbs. A torque wrench is essential for this.
What tools do I need to mount a scope?
At a minimum, you need correctly sized screwdriver bits, a torque wrench (inch-pound), levels, and thread-locking compound. A gun vise is highly recommended for stability during the leveling process.
Can I mount a scope without a torque wrench?
It is not recommended. Guessing the tightness often leads to over-tightening, which can damage your scope, or under-tightening, which will cause the scope to shift under recoil. A torque wrench ensures consistent, correct pressure.
Why won’t my rifle hold zero after mounting?
This is often due to a mounting issue. Check that all screws are properly torqued with thread locker. The scope could be canted, the rings might be misaligned, or the base might be loose. Re-check every step of the mounting proceedure.
How do I know if my scope is level?
Use a two-level system. First, level the rifle itself in a vise using a level on a flat part of the action. Then, place a second level across the flat top of the scope’s elevation turret. Adjust the scope until both levels read the same.
Mounting a scope properly takes patience and attention to detail, but it’s a skill any shooter can learn. By following these steps, using the right tools, and avoiding the common pitfalls, you’ll create a solid foundation for your rifle’s accuracy. Take your time, double-check your work, and you’ll be ready for a successful trip to the range to finalize your zero.