In many cases when a shooter buys a new firearm or even an older one that requires a new set of sight being glass, red dot, or iron, the rifle needs to be sighted in. Much of the time this task is performed by using one of several methods requiring a bore sighting approach to the problem.
Bore sighting is a system that makes use of the naked eye, laser beam, or look through cross-hair system down the bore. This system when directed toward the attached laser at the rifle’s muzzle is nothing more than a simple laser light that will project the general position of the gun’s muzzle on a target some distance away. This distance can range from 10 to 50 yards in most cases at least for the first rounds sent down range to mark an impact point on paper.
Another system is actually to look down the rifle’s barrel from the breech. This is easy with single-shot hinged action or bolt action rifles with the bolt removed. Autoloaders pumps and lever actions are another story and require a bore scope or the laser system mounted again at the muzzle.
The simple system
Let’s assume your bore sighting a bolt action rifle or single-shot hinged firearm. Here is your approach to the bore sighting system. Set the rifle in a firm rest that being sandbags or one of the modern clamp rest bench unit designs. Now, with the bolt removed look down the rifle barrel and aline the barrel with the target dead center. Do this at about 25 yards as it is easier to get on target at close range and at this range you still going to be on paper at 100 yards a bit later on in the process when your bore sighting zero is completed.
With the rifle barrel alined on the targets center ( bull’s-eye) and without moving the rifle, the scope’s elevation and windage adjustments to bring the crosshairs, red dot, or other sub-tensions in alignment with the target center as well. In general, I try and start with the elevation first. With that alined I move to my right or left adjustments which brings the crosshairs or other viewing projections closely in alinement with the target. You can actually watch through the scope as the cross hairs move toward the desired position, Or if the movement is in error you can see that as well. If this seems simple it is because it is exactly that.
Another method regardless of the rifle’s action design is to use a laser red light that is installed on the muzzle of the firearm or chambered from the breech. When installed the red laser beam is the center point of the bore and will project on the target. Like the previous system, the crosshair center is adjusted to reach the exact cent of the target using the red dot impact point of the bore. Often this system is used by sporting goods stores that are selling scope and rifle packages and the buyer wants the system just about field ready out the door. In the area of being field ready I will have more to say on that subject a bit later on.
Live fire bore sighting zero
The previous systems used to bore sight a rifle obviously do not rewire actual shooting, but now comes the system that will require the shooter to go hot. Now the shooter sets up a target at about 25 yards then takes aim at the target center sending a round down range. If the shooter is lucky a bullet impact point will be observed someplace on the target. Almost never is even voles to the bull’s -eye.
With a hit recorded measure the elevation and windage requirements need to run the adjustment scope knobs so as to center the cross hairs for the next shot. Again if done correctly that shot should put you on target. Now, that is all that stated the method I use often is the shoot that first round and measure and adjust one element only and in most cases it is the horizontal line first. Getting that set I fire a second test round to confirm my horizontal line before moving on to my elevation adjustments. With another round sent at the target after again adjust this time for elevation if all goes well the shooter should be quite close to the correct zero. If you are near or on center at 25 yards now move the target to 100 yards for the final actual zero correction. In most cases, the bullet will be coming in high and require some elevation drop using the scope knobs once again.
If you have done everything correctly and carry a bit of luck as well you should be able to zero a rifle to the 25-yard mark with a little practice in three rounds.
The second live fire method often used
In this bore-sighting example simply shoot the first round at the target. With the rifle tight in sandbags or rest system move the crosshairs both directions regarding elevation and horizontal correcting exactly to the point that the bullet hit the target. If the rifle is not moved during this process the rifle is now zeroed using the one shot method.
Never assume anything
With a bore sighted rifle never, and I mean never go afield thinking all is well and your field ready to go to work on game or targets. Believe me far too many hunters have lost a fine trophy because they believed bore sighting was all that was required to get a rifle and sight system into action.
After bore sighting and shoot that test round at 100 or more yards get behind the rifle and shoot at varied ranges thereby learning the exact drop and also if the rifle is shooting accurately as well as being correctly zeroed in the first place. Bore sighting is only the start to getting a rifle fine tuned and up and running. Don’t be the guy or gal that walks out of the gun shop thinking all is well and we are road ready for the upcoming big hunt. Relive me your not!
L.P. Brezny is a highly respected and experienced shotgun expert and author with over 50 years in the industry and testing lab. He has contributed to numerous firearms publications, including Wildfowl, Shotgun Sports, and Varmint Hunters, and is a regular columnist for Gun Digest and AmmoLand News.