When looking over the used rack at the gun shop, it isn’t unusual to find a number of scope-mounted rifles. About half have improperly mounted scopes.
Some are cocked sideways, the adjustment knobs are in the wrong place, or the scope isn’t properly tightened. Sometimes the scope is overtightened, which may damage the scope.
I have even found a scope touching the rifle barrel. I think sometimes that the owner has kept his nice scope and hastily placed a cheap scope in the mount before trading.
But if you purchase a more expensive rifle scope you will need to mount it yourself. While a gunsmith may do the job, this gets expensive.
No matter how good the rifle scope, if the optics aren’t properly mounted and affixed to the receiver, then the scope isn’t going to do the job it is intended for.
Let’s go over some best practices for rifle optic mounting.
Pick the Right Scope
First, choose the scope. There are many good-quality rifle scopes, so choose the one that suits your needs. Use a chart to choose the proper rings and mounts.
(A tip: the scope should be mounted as low as possible. Gone are the days when stocks were designed for iron sights.)
The modern rifle will help place the eye in the proper location for fast, accurate shooting. If the objective lens is large, you may have to compromise a bit on the mounts.
Eye relief is important. Eye relief is simply the distance from the eye to the scope. Eye relief will decrease from low to high power settings.
So, the eye relief should be set so that the scope is useful either at high or low magnification settings.
Another caution— if the rifle is chambered for a more powerful cartridge, beginning with the .308 and certainly the .300 Magnum, be certain that the scope isn’t set where it will whack your brow in recoil.
The eye should be able to quickly pick up that centered circle of light for aiming. I find about three inches of eye relief works for most shooters.
To properly focus the ocular lens, commonly called the eyepiece, simply take an aim with a triple-checked, unloaded rifle at a solid, colored target 10 to 20 yards away.
Turn the eyepiece until the sight picture is clear and in focus.
Create a Secure Foundation
Scope bases and mounts are important. Modern Picatinny rails make mounting simpler. But bolt-action rifles, in particular, use individual mounts on the receiver bridge.
The scope bases must be securely mounted to the receiver. The distance that separates the mounts must correspond to the space between the rings on the scope.
When mounting the bases, I tighten each screw a bit, then the other screw, and so on. I don’t tighten one too much at first, I even things out.
As you work the screws, the base or mount will be tight and secure to the receiver. While it seems odd, occasionally you will run across screws that are too long, especially in used guns with hasty mounting.
After the bases are properly mounted, use Loctite to be certain they are secure. If you overtighten, the threads may be stripped.
Make Sure Everything’s Aligned
As you move to mounting the rings, mounting them evenly and properly centered is important.
A professional may use a special tool but the average shooter may be able to mount the rings with care.
Slip the rings in place and be certain that there are no burrs in the rings. Occasionally, it is necessary to lightly sand and polish the rings.
I have taped the inside of rings to ensure the rings don’t scratch the scope tube. There cannot be any binding of the rings. The scope tube may even be damaged.
The ring edges are especially a point of interest. Be certain the rings are properly lined on the scope body.
While it is ok to get the rings tightened to an extent, be certain that you have enough of a loose fit to allow the scope to move a bit as you adjust eye relief.
It is surprisingly difficult to get the reticle perfectly centered. This is the single most common demerit I have observed in used rifles and rifle scopes in shops.
They are traded in like this. When the rifle is quickly mounted and the stock solid in the shoulder, the eye should naturally go to the eyepiece and find the reticle.
When this alignment is properly set up, the rings should be tightened slowly and carefully, making certain not to lose the proper adjustment.
Move On to Bore Sighting
Look through the bore and then you will find a spot on the wall or perhaps out the back yard window, and then adjust the scope to set the reticle on this target.
The windage turret adjustment moves the crosshairs right or left, the elevation adjustment moves the reticle up and down. This is called bore sighting.
There are devices called collimators that use a spud of caliber diameter to mount in the barrel. The reticle is adjusted against an aiming point in the collimator.
These are neat tools and so are laser bore sighters. I use the method of boxing in the shots on the target.
I begin firing at 25 yards. If the rifle has been properly bore-sighted, the rifle will group nicely on paper. I fired a shot and then I move the adjustment turrets.
I normally work only one turret at a time. If the scope is properly mounted, it isn’t difficult to get in line quickly.
I move the turrets the specified amount—usually a click equals a quarter inch—and get in line.
Once a single bullet hits in the proper spot, I move to the next option, usually beginning with windage and then moving to elevation.
I usually set the point of impact, versus point of aim, for two inches high at 25 yards.
Finish and Fine Tune
Despite advanced apps, formulas and electronic and mathematical wisdom, I find that only actual firing is reliable for fine-tuning the point of impact.
I like to set a hunting rifle for an inch to two inches high at 100 yards, achieving a shoot flat hold to 125 yards. It depends on the use the rifle will be put to.
A wild boar rifle might be used at fifty yards, a deer rifle at one-hundred to two-hundred yards, and a varmint rifle, well, the distance at which you can see the critter.
Follow these simple rules, enjoy your range time and get your optics sighted correctly.
Do you have any favorite scopes or mounting options? Let us know in the comments below!