How to Boresight a Rifle Scope: 5 Step Guide

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By Bryan Lynch •  9 min read

You have your new rifle. You have chosen your optic and it is mounted properly. Now what?  Before you head out to the range to zero that scope, there are a few things to accomplish. One is to use a boresight to align your scope with the bore of your file. Bore sighting will make bringing your scope to zero much easier and faster.

Bore sighting is not difficult nor time-consuming. The easiest method of bore sighting your rifle is to use one of the many boresight tools available at almost any sporting goods or gun store. Some bore sighting tools rely on laser technology to align your scope. Other styles of boresights utilize a rifle-mounted aiming system to align the scope with the rifle’s bore.

Both systems can work well. However, I prefer the laser style of the bore sighting tool. Using a laser boresight is often easier and can be much more accurate than a muzzle-mounted optical boresight. The steps I will outline in this article apply to most laser boresight styles on the market today.

Choose Your Laser Boresight

There are two basic styles of laser boresight tools.

Each has its advantages and disadvantages. Understanding the advantages and disadvantages of each allows you to decide which style of boresight tool best fits your needs and goals.

Muzzle Inserted Laser Boresight Tools

Many of the most economical boresight tools use an arbor, often called a spud, inserted in the muzzle to hold the laser. The arbor aligns the laser with the rifle’s bore projecting the laser beam downrange toward a reflected target. You then align the crosshairs on the scope with the reflected laser dot on the target.

The advantage of an arbor style laser bore sighter, apart from the inexpensive cost, is the flexibility. Most muzzle inserted laser bore sight tools have adapters or sleeves for different calibers. The downside to muzzle arbor laser bore sighters is the inconsistency inherent in the design. Users of any laser bore sighter must understand that you cannot zero a scope using a laser bore sighting tool. Zeroing can only be done at a range using live ammunition.

Chamber Inserted Laser Boresight Tools

The other popular style of laser boresight tool is a chamber inserted laser. Many of this style of laser bore sighter is caliber specific. The laser is a replica of the cartridge for which the rifle or pistol is chambered.

This design of laser bore sight tool inherently more accurate than a muzzle arbor bore sight tool. If the laser bore sight is properly manufactured and fits the chamber tightly, the bore sighting tool’s laser beam will follow the expected line of the rifle bore very closely. You must also consider the ballistic trajectory of the bullet as it travels. Laser light tends to travel flat and straight, unlike a rifle or pistol bullet. Gravity, air resistance, and mass don’t affect the line of a laser beam.

The Things to Remember About Bore sighting

Before you begin the bore sighting process, there are some factors you should consider about your expectations of the bore sighting process.

Bore sighting is not a substitute for range sighting your rifle or pistol. The bore sighting of your rifle or pistol is only one step in the process. Many shooters skip the bore sighting step altogether and are successful in zeroing their rifle or pistol perfectly.

Be careful when bore sighting your rifle or pistol, especially if you use a caliber-specific chamber bore sighting tool. These types of tools are so like real ammunition there is a danger the two will be confused. We suggest that you never boresight your rifle or pistol in a space where live ammunition is present.

Pay attention to what the bore sighting tool is telling you. If your scope is significantly off after mounting, there is either something wrong with the bore sighting tool, or your scope is not mounted properly.

Bore sighting tools are an efficient and effective way to check your rifle or pistol scope accuracy quickly. We suggest that a laser bore sighting tool should be a part of every shooter’s kit.

Using a Bore Sighting Tool – A Step by Step Guide

Following a step-by-step procedure, each time you use your laser bore sighting tool will enable you to achieve consistent results. The steps outlined below should work with either a cartridge style or muzzle arbor style laser bore sight.

Step 1 – Be Safe. Double Check Your Rifle or Shotgun

Safety is the paramount issue when doing any kind of rifle or pistol maintenance. Establishing a set of protocols for safe firearms handling helps forestall most accidents. This list is our suggestions for safe firearms handling and maintenance routine.

Step 2 – Set up Your Bore Sight Range

You will need a range set up at a specific distance to use your laser bore sight tool adequately. We suggest a 25-yard range if possible. Some gun owners may not have enough space to set up a 25-yard range. Even most residential homeowners can manage 75 feet of unobstructed space to set up a bore sighting range.

We suggest using a reflective target for your boresight range to see the reflected laser light. If you are bore sighting outdoors, bright sunlight can make the laser spot hard to see. A reflective target will help. Using a green laser can also be advantageous when bore sighting a rifle or pistol in bright sunlight.

A table or bench is also necessary to provide stable support for your rifle or pistol. You will be adjusting your scope or optic during this process. The ability to use your hands and keeping the firearm supported and in position is a key point.

Step 3 – Set up Your Firearm and Your Bore Sighting Tool

Step 4 – Bore sighting the Scope

Support your file or pistol on sandbags or a rest pointed downrange. Adjust the firearm and place the crosshairs of the scope on the center of the target. Look for the laser dot on the target. The difference in windage and elevation from the laser dot to the crosshairs represents the adjustments you need to your scope.

Using the windage and elevation turrets, move the scope adjustments until the laser dot and the scope’s crosshairs are both on the center of the target. At this point, your rifle and scope are bore-sighted for the length of your bore sighting range.

Remember that this is not the same as range sighting or zeroing your scope. You must still go to the range and zero your scope using live ammunition. The action of bore sighting is only the first step in bringing your rifle and scope into an accurate zero configuration.

Step 5 – Remove the Boresight and Safely Store Your Firearm

Once you have completed your bore sight process, you should recover your bore sight tools, store them in their correct place, safely store your firearm, and return your workspace to a clean and organized condition.

What are the Advantages of Bore sighting a Rifle Before Zeroing?

Bore sighting offers several distinct advantages to shooters who are in the process of zeroing a rifle and scope.

Bore Sighting Saves Time and Money

Bore sighting before you go to the range for zeroing saves both time and money. A well-bore-sighted rifle or pistol takes less time and fewer live rounds to bring to zero.

Bore Sighting Can Help Eliminate Mounting Problems

Bore sighting will help diagnose problems with optical sight mounts. If your optical sight is poorly mounted or improperly mounted, it will be almost impossible to perform a boresight with any amount of accuracy. If you can’t bring a scope into a good aiming situation with a boresight, it will be next to impossible to zero.

Solving mounting issues before you go to the range to zero a scope will inevitably mean easier zeroing at the range.

The Practice Adjusting your Scope When Bore Sighting makes Zeroing Easier

Using a bore sighting tool with your scope allows you practice in adjusting your scope using the turrets to adjust windage and elevation. Zeroing often involved making finer adjustments to both windage and elevation. The experience you gain using a bore sighting tool will be invaluable both on the range and in the field.

Becoming a Better Shooter

In the end, adding a laser bore sighting tool you’re your gearbox will make you a better shooter. You will learn more about your firearm, scope, and how they perform together to become an accurate shooting system. We are all after the same thing. We want to be more accurate, more consistent, and more knowledgeable shooters. A bore sighting tool can aid in achieving those goals when used properly.

I hope the tips, tricks, and advice I have offered in this article help make you a better shooter. In the meantime, be safe and shoot straight. If you have advice, tips, or tricks to add to our community, feel free to leave them in the comments section below. We all benefit from each other’s advice and knowledge.

Bryan Lynch

Bryan grew up in the Midwest and spent every waking moment outdoors. Learning how to hunt, fish, read the land, and be self-reliant was part of everyday life. Eventually, he combined his passions for the outdoors, emergency preparedness, and writing. His goal was to spread positive information about this field. In 2019, Bryan authored the book Swiss Army Knife Camping and Outdoor Survival Guide. His second book, Paracord Projects For Camping and Outdoor Survival, is scheduled to be released on March 2, 2021.