Introduction
The world of rifles and optics can seem complex, filled with technical jargon and subtle nuances. Among the crucial elements of a successful shooting setup is the scope mount, a seemingly simple component that significantly impacts your ability to hit your target. Choosing the right scope mount is more than just picking something that fits; it’s about understanding your specific needs and how the mount will influence your shot placement, especially when shooting at varying distances. This article aims to demystify the difference between two prevalent types of scope mounts: the 0 MOA mount and the 20 MOA mount. We’ll break down their characteristics, advantages, disadvantages, and when each is the optimal choice. Whether you’re a seasoned hunter, a competitive shooter, or a firearm enthusiast, understanding this distinction will help you make informed decisions and improve your accuracy.
What is MOA?
Before diving into the specifics of scope mounts, it’s essential to grasp the concept of MOA. MOA, or Minute of Angle, is an angular measurement used to describe the accuracy of a rifle and the adjustments needed for a scope. Think of it like this: imagine a circle. A complete circle is 360 degrees. Each degree can be further divided into 60 minutes. One minute of angle (1 MOA) represents roughly 1 inch at 100 yards, or approximately 2.9 centimeters at 100 meters.
This relationship means that a 1 MOA adjustment on your scope will move your point of impact by roughly one inch at 100 yards, two inches at 200 yards, and so on. This concept is fundamental to understanding how scope mounts and scopes interact to compensate for bullet drop and other factors affecting bullet trajectory. A clear grasp of MOA is crucial for accurately adjusting your scope to hit your targets at various ranges.
What is a Zero MOA Scope Mount?
A zero MOA (0 MOA) scope mount is a base that provides no built-in inclination or upward angle to the scope. This means that the scope is mounted parallel to the rifle’s bore. It aligns the scope’s reticle with the bore of your rifle in a neutral position.
The primary advantage of a zero MOA mount lies in its simplicity and suitability for shorter-range shooting. The absence of any built-in cant allows the scope to utilize its full range of internal elevation adjustment. Because of this characteristic, these mounts are typically the most affordable and simplest to install. They’re well-suited for rifles and calibers where bullet drop is less significant at shorter distances. These mounts work well for those who are primarily target shooting at a range with known distances.
Zero MOA mounts are ideal for:
- Shooting at ranges typically under 300 yards.
- Rifles chambered in calibers with relatively flat trajectories (e.g., many .223/5.56 rifles).
- Situations where the shooter doesn’t anticipate needing a substantial amount of elevation adjustment.
- Close-range hunting.
- Situations where the shooter does not want any extra inherent adjustment.
However, it’s essential to consider the potential drawbacks. As you extend the distance, bullet drop becomes more pronounced. With a zero MOA mount, you’ll rely entirely on your scope’s internal elevation adjustments to compensate for this drop. For exceptionally long ranges, this might result in running out of elevation adjustment, preventing you from correctly sighting your target.
What is a Twenty MOA Scope Mount?
A twenty MOA (20 MOA) scope mount is designed to provide a built-in upward angle to the scope relative to the rifle’s bore. This inclination, specifically 20 MOA, effectively points the scope slightly upwards. This slight angle helps the scope compensate for the effects of gravity on the bullet’s trajectory over greater distances. The effect of this is to give the user extra elevation adjustment.
The 20 MOA mount is essentially canting the scope forward, adding an extra 20 MOA to the elevation adjustment of your scope. This cant is designed to help you shoot at longer ranges than would be possible with a 0 MOA mount. The added upward cant provides more adjustment to compensate for bullet drop over long distances.
These mounts are particularly valuable for:
- Long-range shooting, allowing you to extend your effective range.
- Rifles chambered in calibers with significant bullet drop at extended distances (e.g., larger hunting calibers).
- Shooting beyond the range where a scope without additional adjustment would be effective.
- Competitive shooting where precise adjustments are required.
- Hunting in mountainous or other challenging terrains.
The primary advantage of the 20 MOA mount is that it significantly expands the effective range of your rifle and scope. It helps you utilize more of your scope’s internal elevation adjustment, allowing you to engage targets at extreme distances. The built-in cant allows you to dial in more elevation on your scope, further compensating for bullet drop and other factors that affect trajectory.
Making a Direct Comparison
To best understand the differences, let’s directly compare these two types of mounts, focusing on key aspects:
| Feature | Zero MOA Mount | Twenty MOA Mount |
|---|---|---|
| Built-in Elevation | None | 20 MOA upward cant |
| Best For | Shorter to medium range shooting. | Long-range shooting. |
| Bullet Drop Compensation | Relies entirely on scope’s internal adjustments. | Reduces the need for internal elevation adjustments, enabling greater use of the scope’s adjustment range. |
| Typical Applications | Target shooting at known distances, hunting at shorter ranges, and calibers with flatter trajectories. | Long-range target shooting, long-range hunting, and calibers with significant bullet drop. |
| Advantages | Simple, allows maximum use of scope adjustment for closer ranges, generally more affordable. | Extends the range of a rifle system, helps accommodate substantial bullet drop, allows for more adjustment range. |
| Disadvantages | Limits elevation adjustments at longer ranges. | May not be necessary or optimal for short-range shooting, can potentially lead to over-correction if not used correctly, often more expensive. |
This comparison should highlight the significant differences and the scenarios where each type of mount truly shines.
Considering Important Factors When Choosing a Scope Mount
The choice between a zero MOA and a twenty MOA scope mount is a crucial decision that requires careful consideration of several factors. Understanding these aspects will ensure you select the right mount for your needs.
- **The Shooting Distance:** This is, arguably, the most critical factor. If you primarily shoot at ranges under a few hundred yards, a zero MOA mount might be sufficient. However, if you intend to engage targets at longer ranges (beyond 500 yards), a twenty MOA mount is generally recommended.
- **Rifle Caliber and Bullet Ballistics:** Caliber has a significant impact on bullet drop at various distances. Heavier, slower bullets (such as those from some larger hunting calibers) experience more dramatic drops than lighter, faster bullets. For rifles with heavy bullet drops, the twenty MOA mount is especially important.
- **Scope’s Elevation Adjustment Range:** Before choosing a mount, consider your scope’s available internal elevation adjustments. Some scopes have a limited range, and in these cases, the twenty MOA mount can be invaluable. It provides additional elevation to help engage targets at further ranges.
- **The Type of Shooting You Prefer:** Target shooters and hunters will have different requirements. Target shooters at fixed ranges may not need a twenty MOA mount, whereas those competing at longer distances will. Hunters, especially those who pursue game at unpredictable distances, may find the flexibility of a twenty MOA mount beneficial.
- **Specific Shooting Needs:** Consider your typical shooting scenarios and requirements. If you know the distance will be fixed, you may not need a 20 MOA mount.
- **Scope Mounting System:** Ensure the chosen mount is compatible with the type of rail on your rifle (e.g., Picatinny, Weaver).
Carefully considering these factors helps you make a well-informed choice, ensuring you select the best mount to enhance your shooting performance.
Practical Examples to Illustrate the Difference
Let’s look at some examples to demonstrate how each mount would be implemented:
- **Scenario:** A marksman is practicing at a shooting range with known distances, such as 100, 200, and 300 yards, with a .223 rifle.
- **Recommendation:** A zero MOA mount is likely sufficient in this situation. The .223 round has a relatively flat trajectory at these ranges, meaning minimal compensation is needed from the scope. The shooter is able to use their scope’s adjustments effectively.
- **Scenario:** A long-range hunter is planning to hunt in open terrain where shots could potentially extend to 600+ yards, using a .300 Winchester Magnum rifle.
- **Recommendation:** In this case, a twenty MOA mount is ideal. The .300 Win Mag has a ballistic profile where the bullet drop is significant at extended distances. The 20 MOA mount gives the hunter the adjustment necessary to compensate for bullet drop and ensure the bullet hits its mark at longer ranges.
These examples illustrate the practical impact of these mounts in different shooting scenarios.
Mounting Pointers and Considerations
Regardless of the scope mount you choose, proper installation is crucial for optimal performance and accuracy. Here are a few tips:
- **Follow Manufacturer’s Instructions:** Always follow the instructions included with your scope mount and scope.
- **Torque Settings:** Use the recommended torque settings for the screws. Over-tightening can damage the mount and scope. Under-tightening can affect stability and zero consistency.
- **Leveling:** Ensure the scope is level with the rifle. A canted scope can lead to inaccurate shots, particularly at longer ranges. Leveling can be accomplished with a level or leveling tools made for firearms.
- **Bore Sighting:** Perform a bore sighting to get the scope roughly aligned with the bore of the rifle before final adjustments.
Conclusion
Choosing the right scope mount is a crucial aspect of building an accurate rifle setup. As this discussion highlights, the primary difference between a zero MOA and a twenty MOA scope mount revolves around their impact on elevation adjustment. The zero MOA mount is best for shorter-range shooting and situations where a full range of scope elevation is not a necessity. The twenty MOA mount is ideal for those intending to shoot at extended ranges where bullet drop becomes a significant factor. Understanding these nuances will help you choose the correct mount. Evaluate your primary shooting distances, rifle caliber, and scope’s capabilities before making your decision.
By making an informed choice and installing your scope mount correctly, you’ll be well on your way to improving your accuracy and enjoying your shooting experience. Consider your needs, conduct thorough research, and choose the mount that is ideal for your personal shooting style and requirements. The right scope mount will enhance your long-range shooting.
