The Foundation: Setting the Stage
Before we dive into the specifics, it’s essential to understand the role a scope rail plays. This rail, mounted atop the receiver of your rifle, provides a stable and secure platform for attaching your scope. The angle of this rail has a direct bearing on the available adjustment range within your scope. The cant, or inclination, of the rail is critical in the relationship between the scope’s adjustments and the bullet’s trajectory.
Understanding MOA and Scope Adjustments
Minute of Angle, often simplified as MOA, is an angular measurement used in the world of shooting. It represents an angle of 1/60th of a degree. At 100 yards, one MOA equates to approximately 1 inch. This means that if your point of impact (POI) is one MOA away from your point of aim (POA) at 100 yards, your shot will land roughly one inch away. These are the units that are used to adjust the scope’s reticle to compensate for wind, bullet drop, and other factors that affect the trajectory of a bullet.
The fundamental idea is that when you adjust your scope’s elevation or windage, you are effectively changing the angle at which the scope is looking at the target. This angle is translated into the adjustment of the scope’s reticle. All of this is why understanding your optics and how they interact with your rail is essential.
Zero MOA: Flat and Focused
The zero MOA rail is the straightforward, foundational choice. It offers a perfectly flat surface, with no built-in cant. This means the scope sits parallel to the bore of the rifle. The benefit of this configuration is a simple and straightforward zeroing process. When you sight in your rifle, the scope’s adjustments are directly aligned with the bore. The reticle starts from a centered position and adjusts to make corrections based on factors such as distance, ballistics, and the environment.
Zero MOA rails are the most common type and are often found on rifles used for general purpose shooting, hunting at shorter ranges, and close-quarters combat (CQB) applications. This setup is generally preferred when you need a scope that is optimized for a wide variety of distances and shooting situations, where most shots will be taken at a range of a few hundred yards or less.
Advantages of 0 MOA Rails
The key advantage of a zero MOA rail is its simplicity. The zeroing process is often more intuitive, and you’ll likely use a smaller range of elevation adjustment to sight in your rifle. This means you have a greater allowance for adjustment in your scope, which is critical if you plan to switch ammunition, deal with significant elevation changes during your shooting, or shoot at distances slightly shorter or longer than you are used to.
The 0 MOA rail is also a solid choice if you are utilizing a scope with a limited elevation adjustment range. This can be due to budget constraints, using a scope from another rifle, or preferring the simple, uncomplicated nature of a particular scope.
Disadvantages of 0 MOA Rails
A potential disadvantage is the limitation it places on long-range capability. If your goal is to consistently hit targets at distances greater than 500 yards, or even 300 yards, you might find that you run out of elevation adjustment in your scope before you can reach your target.
Twenty MOA: Reaching Further
The twenty MOA rail introduces a subtle, yet significant, angle. It has a built-in cant of twenty minutes of angle, meaning the scope is angled slightly upward relative to the bore of the rifle. This seemingly small tilt has a profound effect on the scope’s elevation adjustment capabilities.
Advantages of 20 MOA Rails
The primary advantage of a twenty MOA rail is its ability to extend your rifle’s effective range. By tilting the scope upward, you’re effectively “pre-setting” some of the elevation adjustment needed to compensate for bullet drop at longer distances. This means that when you zero your scope, you can start with your reticle already adjusted upward, leaving more usable elevation for distant targets. The idea is to keep the scope’s adjustments centered or near center to maximize the resolution and minimize the internal distortions of the optics.
This system provides you with significantly more elevation adjustment available in the scope’s internal adjustments. This can be critical for longer distances, where the bullet drop can be considerable. A twenty MOA rail allows you to dial in significantly more elevation to compensate for the bullet’s trajectory without having to compromise the scope’s adjustment range.
For long-range shooting, precision rifle competitions, or any scenario where engaging targets beyond 500 yards is a common occurrence, the twenty MOA rail is often the preferred choice.
Disadvantages of 20 MOA Rails
However, the twenty MOA rail is not without its considerations. One potential drawback is the more complex zeroing process. You may have to adjust your scope significantly in order to properly sight in your rifle at shorter distances. Additionally, some shooters may find that the 20 MOA setup requires more initial adjustments, leading to slightly less precision at shorter ranges.
Choosing the Right Rail for Your Rifle and Needs
Selecting the appropriate rail is not a one-size-fits-all decision. Several factors play a vital role:
Consider your planned shooting distance. If you primarily engage targets at shorter ranges (under 300 yards), a zero MOA rail might suffice. However, if you frequently shoot beyond that, the twenty MOA rail is likely the better option.
Evaluate your scope’s elevation adjustment range. Check the specifications to determine the total adjustment range (in MOA). If the scope has a limited adjustment, a twenty MOA rail becomes even more critical for long-range shooting.
Consider the caliber and ballistics of your ammunition. Heavier bullets with a lower ballistic coefficient will drop more at any given range, requiring more elevation compensation. The heavier the bullet, the more you may want to lean on the benefits that a twenty MOA rail can provide.
The type of shooting matters. Are you hunting, competing in precision rifle events, or engaging in recreational target shooting? The demands of each discipline will help determine the best rail choice. If you are frequently changing distances and scopes, the zero MOA rail can give you more versatility.
Recommendations and Real-World Examples
As a general rule, use a zero MOA rail for short to mid-range shooting and a twenty MOA rail for long-range applications. Here are some specific scenarios:
A shooter with an AR-15 chambered in 5.56x45mm NATO, primarily engaging targets at 100-300 yards, would likely be fine with a zero MOA rail.
A precision rifle chambered in 6.5 Creedmoor or .308 Winchester, used for shooting beyond 500 yards, would almost certainly benefit from a twenty MOA rail.
Installation Essentials
Proper installation of a scope rail is critical. Ensure the screws are properly torqued to the manufacturer’s specifications. Use a torque wrench to avoid over-tightening, which could damage the receiver, or under-tightening, which could allow the rail to shift.
The rail should be compatible with your receiver, scope rings, and the scope itself. The standard is to use a picatinny rail, but there are some other options for some rifles. Be certain that the rail matches the type of rifle you are using.
Use a bubble level or other leveling tools to ensure the scope is aligned properly to the rifle, or the proper use of the scope rings is going to be difficult. Proper alignment will lead to better accuracy and a more consistent point of impact.
Final Thoughts: Making the Informed Choice
The choice between a zero MOA and a twenty MOA rail is a crucial one for any serious shooter. The correct rail can vastly improve your accuracy and extend your rifle’s effective range. Before making a decision, take the time to assess your shooting needs, your scope’s capabilities, and the distances you typically engage targets.
Consider the kind of rifle you plan on mounting the rail on and the purpose it will be used for. A plinking rifle that will be used for fun and recreational target shooting will be different from a rifle used for competition or hunting.
Ultimately, the goal is to choose the rail that best optimizes your setup and allows you to consistently hit your targets.
If you are planning to use your rifle for shooting at a range of 500 yards or more, a twenty MOA rail can be a significant advantage. If you are new to shooting or are unsure which rail is best, research and consult with other shooters to find the best option for you.
Now that you have some basic information, take the time to assess your shooting habits, shooting needs, and the type of scope that you are using to select the perfect scope rail for your rifle. If you do, then you will be on the right track to a more accurate rifle system.
