Proper scope mounting is critically essential for good accuracy. Do you know how to mount your optic properly?
Brad Fitzpatrick
Some guns seem cursed. For one reason or another, they do not shoot well, and you can invest hours or days investigating every variable that could result in poor accuracy. However, after years of shooting from a bench and countless hours spent exorcising the accuracy demons that seem to plague certain rifles, I’ve found that the cause of most misses is simple: the shooter hasn’t properly mounted the optic.
In some instances, issues with optics are easy to diagnose. Such was the case of a poor chap who mounted his scope backward. His mistake, though, can be forgiven. He was a rank amateur and admittedly had no idea what he was doing. Mounting issues are rarely so obvious, and often, resolving the issue requires completely removing and remounting the scope.
You can save yourself the trouble, though, if you mount your scope properly in the first place. Let’s run through the process of scope ring and base selection. Then lets tackle proper scope mounting so that you can bypass the headaches and heartbreak associated with poorly mounted optics.
Scope Base and Ring Selection
The first step in mounting your optic is to purchase bases if required. Some modern rifles are equipped with Picatinny rails. If that’s the case, you’ll only need rings to mount your scope. The same applies if your gun has integral bases machined to the receiver. If your rifle doesn’t come with a rail or integral bases, you’ll have to order them, but they are generally affordable, and selecting the right scope bases is straightforward.
One- and two-piece scope bases are available. As the name suggests, two-piece bases include separate front and rear bases, while one-piece bases are single-mounting rails secured in front of and behind the action opening. One-piece bases are sized to fit different action lengths, so a one-piece base for a short action will typically not be long enough to install on a long action. Action length seldom matters when buying two-piece bases.
You’ll need to choose rings that match the main tube diameter of your scope. 30mm is the most common main tube diameter. Still, several one-inch scopes are still on the market. Scopes with 34 or 35-mm main tubes are rarer still; these are almost all dedicated long-range target scopes.
I like to mount my scope as low as possible on my rifle without interfering with its operation. If you have a 1-5×20 scope, this might mean low rings will work. However, if your scope has a particularly large objective lens in the 52 to 56mm range, you may have to buy tall scope rings. I prefer my scope as low as possible to retain a firm cheek weld on the rifle to better manage recoil.
The objective lens isn’t the only part of your scope that can interfere with the operation of your rifle. In some instances, the magnification dial may contact the rear portion of the receiver, making it impossible to mount the scope. The solution is usually the same as with an oversized objective lens: bigger rings. But the taller the rings, the higher your head must be so it’s correctly positioned behind the scope. That may even mean lifting your head off the comb. In these instances, I add a comb riser to the stock to rest my face against something while I shoot.
That is unless I’m shooting a rifle in Browning’s X-Bolt 2 series with a composite Vari-Tech stock with an adjustable comb. Adjusting comb height is critical, especially when the optic elevates off the receiver.
Scope Mounting
Before I begin mounting my optics, I clean the bases, rings, and rifle receiver with alcohol. This degreasing ensures that the metal components are clean and free of moisture or debris.
If you retain a single bit of advice from this article, then let it be this: proper scope mounting requires tightening all screws to manufacturer specifications, and that requires a torque wrench that accurately measures inch/pounds of torque. The most common mistake that shooters make when mounting an optic is improperly torquing scope rings and bases. Too little torque and the optic will not be stable; too much, and you might damage your scope. Most scope rings and bases do not require much torque to be properly tightened. The bases may need 25 or 30 pounds, but ring torque settings are often as light as 15 or 18 pounds. It’s hard to hit those numbers with a standard wrench. Buy or borrow a torque wrench for scope mounting.
Using a leveling kit or a plumb line, the scope should be leveled correctly in the rings. A minor offset won’t make much difference at close or moderate ranges, but if you want to reach out and ring steel a half mile or more away, you won’t be able to do so with a misaligned optic.
This is also the time to adjust eye relief, so move the scope back and forth in the rings until everything is aligned correctly and you can see edge-to-edge within the scope without the “tunnel” effect that occurs when a scope is too far away. I’ve grown to strongly dislike a scope mounted too far forward on the rifle. This requires me to crane my neck to align my eye with the scope.
Once the scope is level and the eye relief is appropriately adjusted, you can tighten the rings to proper torque specifications. It’s worth noting that scope screws should be tightened in an alternating diagonal fashion. In other words, if there are four ring screws (two left, two right), don’t tighten the left, right, or front screws first. This will place uneven pressure on the optic.
When you’ve finished mounting the scope, you can bore sight the rifle. This process requires placing a laser near the center of the bore and aligning the crosshairs of the scope with the laser dot on the target. The result is usually rough accuracy. You’ll have to fine-tune the rifle’s zero. Bore sighting can save both time and money.
Once your rifle is shooting good groups, double-check the torque specs. Some people use a locking agent on the threads of their scope ring/base screws, but I do not. I’ve found that when torqued to proper specs, scope bases and rings hold just fine without locking material.
Long-range accuracy is all about consistency, You’ll never be a consistent shooter unless your scope is properly mounted. Take some extra time now to properly mount your scope so you don’t have to remount your rifle optic down the line. Once you have your optic dialed-in, you can make long shots on target.
