Understanding the Essentials of Zeroing
Bullet Weight Matters
The weight of your bullet significantly affects its trajectory. Heavier bullets, in general, tend to retain their velocity and resist wind drift better than lighter bullets, leading to a flatter trajectory over longer distances. They are often preferred for hunting applications where penetration and impact energy are paramount. Lighter bullets may offer a flatter trajectory at the expense of wind resistance.
Muzzle Velocity – The Initial Push
Muzzle velocity, the speed at which the bullet exits the barrel, also significantly impacts trajectory. Higher muzzle velocities generally translate to flatter trajectories, allowing for more manageable holdovers at extended ranges. However, higher velocities can sometimes increase recoil and may affect barrel life.
Ballistic Coefficient – Air’s Resistance
The Ballistic Coefficient (BC) is a numerical value that indicates how efficiently a bullet cuts through the air. A higher BC means the bullet is more aerodynamic and will experience less drag, resulting in a flatter trajectory and less wind drift.
Environmental Influences – the Wind and Beyond
The wind, temperature, and altitude can also influence your bullet’s flight path. Wind, of course, can push the bullet sideways, while temperature and altitude affect air density, altering how much the bullet drops.
Selecting the Right Zero Distance
Zeroing for Hunting
Hunters have different priorities. For shots under a hundred yards, the trajectory may be relatively flat. For longer ranges, however, understanding the drop becomes more critical. Consider the type of game you’re pursuing and the environment you’ll be hunting in.
Short-Range Hunting
For hunting at relatively close distances (under 200 yards), a zero at 100 yards or even slightly closer might be ideal. This zero will provide a relatively flat trajectory, allowing for minimal holdover or adjustment for most shots.
Long-Range Hunting
When hunting at longer distances (over 300 yards), a 200-yard zero is often a popular choice. This zero allows you to engage targets at various distances with minimal adjustment, but requires a good understanding of your bullet drop at different ranges. Many hunters also utilize a ballistic calculator to determine precise holdovers, taking into account bullet characteristics, environmental conditions, and target distance.
Ethical Considerations
Always prioritize ethical hunting practices. Know your effective range and the limitations of your equipment. Avoid taking shots that are beyond your capabilities or where you might not be able to make a clean and humane kill.
Zeroing for Target Shooting and Precision
Target shooters need a very precise zero. Disciplines like benchrest or F-Class demand incredible accuracy. Shooters often “dial in” their adjustments using their scope’s turrets, making precise adjustments to compensate for bullet drop and wind drift at various ranges. The zeroing distance will depend on the specific discipline, the target range, and the shooter’s preference. A 100-yard or 200-yard zero is common, but some shooters may choose a zero at a greater distance.
Tactical and Military Zeroing
Tactical or military applications often involve quick target engagements at varying distances. The chosen zero must provide a good balance between point-blank range and the ability to accurately engage targets at longer distances. Common practice is to zero at a range that’s appropriate for the likely engagement distances.
Bullet Weight and Trajectory
As previously mentioned, bullet weight and its impact on trajectory are very important. For example, if you shoot a 150-grain bullet at 2800 fps, you will likely have a different trajectory than someone shooting a 175-grain bullet at a slightly lower velocity. Heavier bullets, like those weighing 175-200 grains, will have a steeper drop and more wind deflection. Lighter bullets, around 150 grains, will likely have a flatter trajectory.
Recommendations Based on Weight
As a general recommendation, a 100-yard zero with lighter bullets can work well for shorter-range, while the 200-yard zero offers a good balance for longer shots with heavier bullets.
Scope Height and Impact
A higher scope mount will change the bullet’s path, due to the increased “offset”. The bullet must “climb” to intersect the line of sight.
Calculating Offset
When determining your zero, take scope height into account to improve your chances of hitting your target at the preferred range.
Zeroing Your .308 Rifle: The Step-by-Step Guide
Gathering Your Gear
Before heading to the range, gather all necessary equipment. This includes your .308 rifle with a properly mounted scope, ammunition (choosing quality, consistent ammunition is crucial), a sturdy shooting rest or support (bench, bipod, sandbags), a target, and any necessary cleaning supplies. It is recommended to have at least one box of the ammunition you want to use.
Preparing Your Rifle
Ensure your rifle is clean and in good working order. After mounting the scope, you’ll want to bore sight the scope. This process aligns the scope’s crosshairs with the bore of the rifle to get you on paper quickly. This can be done with a bore sighter, or by looking through the barrel and aligning the crosshairs with the target.
Setting Up and Initial Shots
Place the target at the distance you selected. Secure your rifle in a stable shooting position using your rest. Load your rifle, take a deep breath, and gently squeeze the trigger, focusing on your sight picture.
Adjusting Your Scope
Based on where your shots land on the target, you’ll need to adjust your scope. Most scopes have windage and elevation turrets. Adjust the elevation to move your point of impact up or down, and the windage to move it left or right. Typically, scopes use either MOA (Minute of Angle) or Milliradians (MILs) for their adjustments. Follow the manufacturer’s instructions for your scope.
Fine-tuning and Confirmation
After making adjustments, fire another group of shots to confirm the adjustments. Repeat this process, refining your adjustments until your point of impact aligns with your point of aim at the target distance.
Documenting Your Settings
Once you have achieved your desired zero, take notes of your scope settings. Write down the bullet weight, zero range, and the settings on your scope for later reference.
Using Calculators
These tools use data about your ammunition and environmental conditions to calculate bullet drop, wind drift, and other factors at various ranges. You can use them to determine the precise adjustments needed for shots at different distances, increasing your accuracy at the target.
Common Pitfalls and How to Avoid Them
Skipping Bore Sighting
This is a critical step.
Unstable Platform
A shaky platform leads to inconsistent results. Always use a solid shooting rest, or other support.
Incorrect Scope Adjustments
Make adjustments carefully, and be sure you understand how your scope’s adjustments work.
Choosing the Wrong Zero Distance
Choose a zero range that fits your typical shooting scenarios.
Ignoring Environmental Factors
Wind, temperature, and altitude can all affect your shots.
Maintaining Your Zero for Optimal Performance
Routine Maintenance
Clean your rifle regularly. Remove any dirt or debris, following manufacturer’s instructions.
Periodic Checks
Always recheck your zero before a hunt, competition, or any event.
Account for Changes
Pay attention to changes in your scope’s zero.
Conclusion
Achieving the **best zero for your .308 rifle** is a fundamental skill that dramatically improves your shooting capabilities. It’s a skill that takes time and practice, but the rewards – increased accuracy, confidence, and ethical performance – are well worth the effort. The perfect zero for your rifle is the one that meets the unique requirements of your use. Remember to consider your intended use, the bullet weight, and scope setup. By mastering these elements, you’ll unlock the full potential of your .308 rifle.
By following the principles outlined in this guide, you’ll gain the knowledge and skills necessary to dial in your .308 and ensure every shot counts.
So, go ahead and try it out. Find a safe range, and experiment.
