Zero to One Mile – Part 2: Scoping Out Success

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After building out the perfect setup in Part 1, it’s time to shift focus to the most critical piece of long-range precision – the scope. A high-quality rifle won’t mean much if the optics aren’t set up correctly. In this part of the series, I’ll walk through how I mounted my scope, figured out the right rail MOA cant to fully utilize the scope’s elevation travel, and ensured everything is balanced and level. Precision shooting at a mile requires more than just slapping on a scope – every adjustment matters, and getting this part right can make all the difference downrange.

Maximizing Scope Vertical Travel Adjustment

One of the key factors in long-range shooting is ensuring that the scope’s vertical travel can be fully utilized. This is where rail cant comes into play. A canted rail – such as a 20 MOA rail on my MPA rifle – tilts the scope downward slightly, allowing the shooter to dial more elevation into the scope. This is essential for extending the effective range of the optic without maxing out its internal adjustments.

Tilting the scope downward through adding cant to the rail or scope mount maximizes the scope’s elevation adjustment by pre-loading the optic in the downward direction. Since long-range shooting primarily involves dialing up for elevation to compensate for bullet drop, starting closer to the bottom of the scope’s travel range allows more upward adjustment. This prevents the shooter from running out of elevation adjustment when engaging distant targets. When selecting the correct cant, consider the internal elevation adjustment of the scope. A scope with greater vertical travel may only need a 20 MOA cant, while scopes with less adjustment range may benefit from a 30 or even 40 MOA cant. The goal is to ensure the scope can zero at shorter distances, such as 100 yards, while still allowing maximum upward adjustment for long-range targets.

Determining the correct cant for your setup is straightforward. Take the total vertical adjustment range of your scope, divide it by two, and subtract 5 to 10 MOA to account for zeroing at closer distances like 100 yards. This ensures you maximize the upward elevation for long-range shots without sacrificing short-distance zeroing.

For example, with a scope that has 100 MOA of total adjustment, the calculation would look like this:

(100 MOA / 2) - 5 to 10 MOA = 40 to 45 MOA

Without cant, the 100 MOA adjustment range is split evenly – 50 MOA up and 50 MOA down. For my setup, I opted for a scope mount that adds an additional 20 MOA cant, giving me a total of 40 MOA cant. This additional cant is crucial for shooting at extreme distances, such as one mile. My scope, the Leupold Mark 5HD, has 29 milliradians (approximately 100 MOA) of total vertical travel. By adding 40 MOA of cant, the usable range shifts to approximately 90 MOA up and 10 MOA down, preserving the majority of my scope’s vertical travel for long-distance shots. This setup ensures I can reach targets at one mile without running out of adjustment, allowing me to stay within the optimal mechanical range of the optic.

Mounting the Scope

Mounting the scope correctly is essential to ensure the optic is level to the base/rail and tracks accurately. Since my MPA BA PRO II comes with a 20 MOA cant, it’s critical to mount the scope level to the rifle’s rail.

Get the Right Tools for the Job

To mount a scope properly, having the right tools makes all the difference. Here's what I use:

  • Torque Wrench – Essential for tightening the scope base and rings to the correct specifications.

  • Leveling Kit – I use a combination of my anti-cant device and a digital leveler to ensure everything is aligned. You can also get a leveling kit like the Wheeler Professional Reticle Leveling System.

  • Gun Vise – The Tipton Ultra Gun Vise is my go-to. It's perfect for holding the rifle securely in place during mounting and doubles as a reliable tool for gun cleaning and maintenance.

Step 1: Level the Rifle

Since my rifle has a 20 MOA cant, I want to mount the scope level to the rail. To do this, I secure the rifle in the vice and make sure the rail is level using a bubble level or digital leveler. As an added precaution, I mount my anti-cant device as a reference level, or I use the barrel clamp level from the leveling kit and attach it to the barrel. This setup ensures that if the rifle accidentally shifts while tightening the scope, I can check the reference level and make necessary adjustments to keep everything aligned.

Step 2: Mount the Scope Base

With the rifle level, I mount the scope base onto the rail. I carefully align it, ensuring everything sits flush. For my setup, I torque the base to 65 ft/lbs, following the manufacturer’s specifications. I also apply a small amount of Loctite to the screws to ensure they remain secure under recoil. This step is crucial because a secure base prevents the scope from shifting under recoil, which could throw off my accuracy.

Step 3: Determine Eye Relief

To adjust for eye relief, I start by setting the scope in the middle of its magnification range. With the scope loosely placed in the rings, I carefully remove the rifle from the gun vise and shoulder it just like I would when shooting. I slide the scope all the way forward within the rings and then slowly move it backward until I can see the entire field of view. During this process, I pay close attention to any scope shadow. The goal is to eliminate all scope shadow for a full, clear sight picture.

Once I find the right position, I crank the magnification up to its highest setting to double-check that the eye relief is still comfortable and shadow-free at maximum power. This ensures my positioning is correct across all magnifications, reducing the risk of eye strain or scope bite when taking long-range shots.

Step 4: Final Torque and Alignment

Once the eye relief is set, I begin tightening the ring screws slowly – about 1/2 a turn at a time – in a crisscross pattern, similar to tightening lug nuts on a car tire. This helps evenly distribute pressure and prevents the scope from shifting. I make sure the spacing between the upper and lower halves of the rings remains roughly equal as I tighten.

I keep a close eye on the reference level during this process because even slight tightening can cause the scope to move. If I notice any shift, I stop and make adjustments to bring it back to level. Following this gradual process ensures that the scope stays aligned and secure.

I’m careful not to over-tighten the screws, as excessive force can damage the scope or affect performance. I always follow the manufacturer’s recommended inch/pound torque specifications to avoid this issue. Taking my time with this step ensures the scope is properly seated and will hold zero, providing consistent accuracy for long-range shooting. This step is crucial for preventing cant and ensuring the scope tracks accurately with the rifle’s bore.

Final Thoughts

When I mount my scope, I know it sets the foundation for accurate shooting. If the scope isn't mounted level to the rifle, it can introduce significant tracking errors. I've found that this misalignment often makes me unknowingly adjust windage to compensate for what seems like elevation issues at long range. Over time, these adjustments can lead to shots drifting off target, even if the rifle and optic are perfectly fine. By making sure my scope is level and secure, I avoid turning windage into elevation, reducing errors and keeping my accuracy consistent.

In the next part, I’ll dive into verifying that the scope is tracking correctly, zeroing the rifle, setting up a ballistic calculation profile, and making the final adjustments for long-range precision.