Understanding Your .308 and Ballistics
Common .308 Rifle Uses
The crisp air, the satisfying weight of the rifle, the anticipation of hitting that sweet spot – the experience of precision shooting is one many find deeply rewarding. Whether you’re a seasoned hunter, a dedicated target shooter, or just someone who enjoys the challenge of hitting your mark, accuracy is paramount. A crucial first step toward achieving that accuracy is zeroing your rifle. And for many .308 shooters, the 50-yard zero provides an excellent foundation. This guide is designed to walk you through the process, helping you understand the principles and techniques needed to get your .308 dialed in for precision.
The .308 Winchester cartridge, a versatile and powerful round, has earned a reputation for accuracy and effectiveness. It’s a favorite among hunters for its ability to deliver substantial energy at various ranges, and target shooters appreciate its inherent accuracy potential. The .308’s popularity also stems from its widespread availability and the diversity of bullet weights and designs available. Knowing how to correctly zero your rifle allows you to unlock the full potential of this cartridge.
When we talk about “zeroing” a rifle, we’re essentially aligning the rifle’s sights (or scope) with the bullet’s trajectory. The goal is to ensure that when you aim at a specific point, the bullet consistently hits that point (or a desired offset). This ensures that your shots land where you intend them to. The more accurate your zero, the more confident you will be when taking those critical shots, whether in the field or on the range.
A good starting point, especially for beginners, is setting up at fifty yards. Shorter ranges allow shooters to more easily manage the complexities of trajectory and bullet drop, allowing you to refine your understanding of the rifle’s performance. It’s also generally easier to see where your bullets are hitting at this distance, making it simpler to make adjustments. This close-range zero also helps in establishing a good foundation for more precise shots at longer ranges.
Let’s dive into the steps involved in achieving a solid zero, understanding your rifle, and improving your accuracy.
Ballistic Considerations
A crucial element of understanding your .308 is understanding its ballistic characteristics. Because of gravity, bullets don’t travel in perfectly straight lines; instead, they arc downwards. This downward curve is known as bullet drop. Knowing how to calculate bullet drop at various ranges is important for making accurate shots.
When zeroing at fifty yards, we aim to establish a reference point. The fifty-yard zero gives you a good starting point, making adjustments easier. The round’s trajectory will begin to drop at longer distances. The 50-yard zero allows shooters to apply a consistent methodology when calculating their trajectory at various ranges.
The ammunition choice significantly impacts the bullet’s trajectory. Heavier bullets generally have a higher ballistic coefficient (BC), which means they retain their velocity and energy better over distance. This translates to less drop and wind drift. Lighter bullets will typically have a flatter trajectory over shorter distances, but they will be more susceptible to wind. Always use high-quality ammunition and note its specific ballistics data. This information is critical for calculating bullet drop and wind drift at further distances.
Equipment Needed
Having the right tools is essential. Here’s what you’ll need for zeroing your .308.
Your rifle and scope will be your most important tools. Make sure your scope is properly mounted and secure. Choose a scope with appropriate magnification for your intended use. Consider a scope with adjustable turrets that allow you to adjust for windage and elevation (up and down) in precise increments (MOA or Mil). Knowing how many clicks each adjustment represents is key to accuracy.
Appropriate ammunition for your .308 is essential. Choose ammunition that matches your intended application (hunting, target shooting, etc.). Use the same ammunition for zeroing and shooting to maintain consistency. Having spare rounds on hand is also prudent.
A good target will provide a clear aiming point. A target with gridlines or aiming points will assist you in seeing where your bullets are impacting. Place the target in such a way that you can see the holes as you take your shots.
A shooting rest provides a stable platform. Use a sturdy bench, sandbags, a bipod, or another rest that keeps the rifle steady during firing. This minimizes shooter error and allows you to accurately evaluate your shot placement.
A spotting scope or binoculars will allow you to evaluate your shots without moving from your firing position. This will save you time and will reduce disruption.
Essential tools like screwdrivers and Allen keys might be needed for scope adjustments. Make sure you have the tools needed for your specific scope.
A rangefinder (optional) will help you to accurately determine the distance to your target.
Preparing for Zeroing
Safety First
Safety is the priority when handling firearms. Thoroughly review and understand all range safety rules before starting. Know your target and what’s beyond it. Always point the muzzle in a safe direction, and never point the rifle at anything you don’t intend to shoot. Never assume a firearm is unloaded; always check it yourself.
Before setting up your rifle, make sure the range is clear, and other shooters are aware of your activities.
The rifle should be mounted securely on your shooting rest to ensure stability. If your scope is new, make sure it is level with the rifle. Proper scope alignment helps ensure that the adjustments you make are accurate.
Carefully measure the distance to your target. Accurate distance measurement is crucial for precise zeroing. The target should be placed at precisely fifty yards from your firing position.
The Zeroing Process at Fifty Yards
Initial Shots
Once you’re set up and safe, it’s time to begin the zeroing process.
Begin by taking a three- to five-shot group. Analyze the impact of your shots on the target. You are trying to determine where your bullets are landing relative to your point of aim.
Adjusting the Scope
Now, assess your shot group’s position. If the group is significantly off-center, you’ll need to adjust your scope. Most scopes have adjustment turrets for elevation and windage. Elevation adjusts for up and down (bullet drop), and windage adjusts for left and right.
For scopes with MOA adjustments (Minute of Angle), one click usually corresponds to a ¼ MOA change. At fifty yards, a ¼ MOA adjustment moves the bullet impact approximately 0.125 inches. Determine how far off from your point of aim your shots are and how many clicks you need to adjust your scope to correct the bullet’s impact point. For example, if your shots are 1 inch to the right and you are using a scope with ¼ MOA adjustments, you will need to adjust the windage knob approximately 8 clicks to the left (¼ MOA x 8 = 2 MOA, 2 MOA x .5 inches = 1 inch).
Make your scope adjustments based on the location of your shot group. Keep track of each adjustment you make. For example, if your shots are low, make adjustments to the elevation dial to raise the point of impact. The direction you turn the adjustment knobs depends on your specific scope. Typically, adjusting the elevation UP will move the point of impact UP. Adjusting the windage to the LEFT will move the point of impact to the LEFT.
Iterative Process
After making your adjustments, take another group of three to five shots to confirm the changes. Repeat this process, taking more shots, adjusting the scope, and evaluating your group.
Once you start hitting your target closer to the point of aim, your zero is becoming more precise. The goal is for your bullet impacts to consistently match your aim.
Zeroing for a Specific Load
Remember that your zero is only valid for the specific ammunition you use. When changing to different ammunition, you must re-zero your rifle.
Fine-Tuning and Testing
Grouping Performance
With the zero established, it’s time to assess your grouping performance. Evaluating group size is key to optimizing the zeroing process.
A good group size shows the rifle’s inherent accuracy. A tight group means your bullets are consistently hitting close to one another.
Testing at Longer Ranges (Optional)
As you become more proficient, you will learn to correct any common errors that can affect your shots, such as flinching, improper trigger control, and sight alignment.
You can test your zeroing further by shooting at longer ranges. To do this, use a ballistics calculator. Input the data about your ammunition. Then, calculate bullet drop and wind drift at increasing distances.
Common Problems and Solutions
User Error
Accuracy can be affected by various factors. Identifying common problems and making corrections will dramatically improve your performance.
User error is a common issue. Flinching and poor trigger control will often result in inconsistent shot placement. Proper sight alignment is also essential. To counter this, use dry-fire practice, focusing on a consistent trigger squeeze and sight picture. Get a qualified instructor to help if needed.
Equipment Issues
Equipment issues can affect performance. Make sure your scope mount is secure. Always check to ensure your scope is properly secured and that the rings are tightened.
Maintaining Your Zero
Checking Your Zero Periodically
A maintained zero is crucial for consistent accuracy.
Schedule regular checks. Check your zero before hunts or when you start a shooting season.
Factors That Can Affect Zero
Changes in temperature can affect your zero due to changes in the air density. Adjust your sights accordingly.
Different types of ammunition will have different ballistic properties, so always use the same ammunition as you zero your rifle.
Storing the Rifle
Store your rifle properly. A safe and secure storage environment helps prevent any damage to your rifle and scope.
Conclusion
Mastering the fifty-yard zero is essential for anyone looking to get the most accuracy out of their .308. This initial step provides a baseline from which you can build a solid foundation for precise shooting. The principles of zeroing, combined with practice and patience, will help you hone your skills and enhance your enjoyment of the sport. Remember to stay safe, practice consistently, and refine your technique. The journey to precision is an ongoing process. Get out there and dial in that .308!
