There’s a moment of truth every shooter experiences, that first trip to the range with a new rifle and optic. You shoulder the firearm, look through the crystal-clear glass, and settle the crosshair on the bullseye. You fire a shot, full of anticipation, only to find the hole in the paper a foot away from your point of aim. This is precisely why knowing how to zero a rifle scope is the most fundamental skill in marksmanship. It’s the process of aligning your point of aim with your point of impact, ensuring that where you put the crosshair is where the bullet will go.
While the concept is simple, the execution requires patience and a solid method. A 100-yard zero is one of the most popular and practical choices for a wide variety of rifles and cartridges, from .223 Remington to .308 Winchester. It provides a flat trajectory for many common rounds, making it effective at both mid-range and closer distances. This guide is designed to walk you through the entire process safely and efficiently. By the end of this How To Zero A Rifle Scope At 100 Yards [A 2025 Step-by-Step Guide], you’ll have the confidence to get your rifle hitting exactly where you’re aiming.
Gathering Your Gear and Preparing for the Range
Before you even think about firing a shot, proper preparation is key to a smooth and successful zeroing session. First and foremost, ensure your scope is mounted correctly. All bases, rings, and screws should be tightened to the manufacturer’s specifications with a torque wrench to prevent shifting under recoil. A loose scope is the number one cause of frustration when trying to achieve a zero.
Next, assemble your range kit. You will need your unloaded rifle and scope, of course, along with ammunition. Bring a solid rest, like sandbags or a bipod combined with a rear bag; this stabilizes the rifle and removes human error from the equation. A large, clear target is essential – a target with a one-inch grid or a “zeroing target” with multiple aiming points works brilliantly. Don’t forget your scope’s adjustment caps, a screwdriver or coin if they require one, and most importantly, eye and ear protection.
How To Zero A Rifle Scope At 100 Yards [A 2025 Step-by-Step Guide]
With your gear ready and your rifle securely placed on a rest at the shooting bench, you’re ready to begin the core process. Follow these steps methodically.
Step 1: The Initial Bore Sighting
While not strictly mandatory, bore sighting gets you on paper faster, saving time and ammunition. Remove the bolt (if it’s a bolt-action) or use a laser bore sighter. Look directly through the barrel from the breech end and center the target in the bore. Without moving the rifle, look through your scope and adjust the windage and elevation knobs until the crosshair is also centered on that same target. This rough alignment means your first shot should at least hit the target paper.
Step 2: The First Three-Shot Group
At the 100-yard line, aim for the exact center of your target. Take a deep breath, relax, and fire three careful shots, focusing on a consistent trigger pull and follow-through. The goal here is not a single hole, but a tight “group” of three shots close together. This group tells you the rifle’s natural point of impact, averaged over multiple rounds.
Step 3: Making the Adjustments
Now, go downrange and retrieve your target. Find the center of your three-shot group. Let’s say your group is 6 inches high and 4 inches to the left of your aiming point. Here’s where you need to know your scope’s specifications. Most modern scopes adjust in Minutes of Angle (MOA), where one MOA is roughly one inch at 100 yards. If your scope has 1/4 MOA clicks, each click will move the point of impact 1/4 inch at 100 yards.
To correct our example: To move the impact down 6 inches, you would need 24 clicks down (6 inches / 0.25 inches per click = 24 clicks). To move it right 4 inches, you would need 16 clicks right (4 inches / 0.25 inches per click = 16 clicks). Always remember the simple rhyme: “Follow the bullet.” If your shots are high, you need to adjust the elevation down. If your shots are left, you need to adjust the windage right.
Step 4: Confirming Your Zero
Return to the bench and fire another three-shot group at the center bullseye. You should see a significant improvement, with the group now centered on or very near your point of aim. It’s rare to get a perfect zero on the first adjustment. You may need to make one or two more fine-tuning adjustments, firing a confirming group each time, until your shots are consistently hitting where you aim.
Helpful Tips for a Flawless Zero
A few extra pieces of wisdom can make all the difference. First, let your barrel cool between groups. A hot barrel can warp slightly and change the point of impact, leading to inconsistent groups and confusion. Shoot a group, then let the rifle sit for a few minutes while you mark your target or hydrate.
Second, consistency is everything. Use the same ammunition you plan to hunt or compete with, as different brands and bullet weights will fly differently. Also, be consistent in how you shoulder the rifle and manage recoil. Any change in your position can alter the zero.
Finally, once you are satisfied with your zero, write down the final adjustments you made and the date. Then, carefully replace the adjustment caps on your scope. This protects the knobs from being accidentally turned.
Final Thoughts on a Confident Zero
Learning how to zero your rifle scope at 100 yards is a rewarding skill that forms the foundation of all accurate shooting. It demystifies your equipment and builds a deeper connection between you and your rifle. By following this step-by-step process—preparing your gear, taking careful shots, making calculated adjustments, and confirming your work—you transform your rifle from a general tool into a precise instrument. With a confirmed zero, you can head into the field or onto the course with absolute confidence in your ability to place your shot exactly where it needs to be.