How to Mount a Rifle Scope for Maximum Accuracy

It’s Day Nine of a 10-day backcountry elk hunt, and you’ve just spotted a big 6x6. He’s a healthy climb up the canyonside, and dusk is threatening. But you’ve got to try. Pushing, you scramble across a creek rimmed with ice and drive yourself up the canyon wall. Brush-busting through the scrub oak and falling several times in the shin-deep snow, you manage to get within range before legal shooting light abandons you. Heaving for breath, you hunker behind the snarled roots of an up-torn pine and tear the scope caps off. The lenses are clean and clear, but a bright aluminum-silver scar through the black anodizing on the tube sets off warning bells in your head. When did that happen? And how? Must have gotten slammed against the granite mountainside during one of your falls.

Did it knock the scope awry? Will you still hit the bull if you shoot?

Nothing is harder on scopes than Western hunting, particularly the unforgiving backcountry. If you hunt enough, sooner or later you’ll fall on or drop your rifle. However, if you mount your scope properly and securely, it will survive most of those falls without getting knocked out of zero.

Step 1: Choose quality mounts and rings

Don’t buy cheap bases and rings. When possible, buy steel—it’s stronger. If you want lightweight aluminum, opt for Talley’s Lightweight Alloy one-piece base/ring units. They’re light, strong, and beautifully concentric. For all-around versatility, get steel Picatinny-spec rail-type bases with multiple cross slots.

Step 2: Install the bases correctly

I worked in a Utah gunshop throughout college. Protocol was to avoid LocTite. Instead, we degreased the screw holes and screws before installing. Without oil present, the screws rarely came loose. However, when I moved to Los Angeles to work at the headquarters of Petersen Publishing, I found that all those degreased screws rusted in the salt-sea air. Four years in the humid environs of Illinois proved even harder on metal.

I now leave the manufacturer-applied gun oil on the parts and use blue LocTite on the screw threads. With a drop on each screw, spin them in until nearly finger tight. Alternating, gradually tighten the screws, while wiggling the bases. This helps center them on the top of the action. After both screws are finger tight and no more play can be felt in the base, torque the screws to the manufacturer’s recommended specs with a quality torque wrench.

Step 3: Install the rings correctly

There are several different basic types of scope rings. The simplest are the Talley combined base/rings mentioned earlier. If you’re using those, skip this step. Most common these days are cross-slot type rings designed for 1913 Picatinny-type bases. These are frightfully strong and easy to install correctly.

Also common are the traditional rings with a twist-in front dovetail and a dual side-screw rear ring. These are the most difficult to get right.

For Western hunting rifles, I like premium “tactical” cross-slot rings made of a combination of aluminum (body of the ring) and steel (lower portion that interfaces with the steel bases). These are usually fit with a very strong crossbolt, which helps on heavy-recoiling hunting calibers. Several companies make good ones.

---

Another advantage of top-shelf tactical-type rings is they’re usually machined from bar stock and interiors rarely need lapping.

To install, simply loosen the securing crossbolt or screws, place the ring in your preferred position on the base, apply forward pressure, and torque the crossbolt to manufacturer’s specifications. (Note: Eye relief and scope mounting dimensions may dictate which cross-slots to use.)

That forward pressure keeps the face of the crossbolt in contact with the face of the cross-slot in the base. This prevents the ring from migrating during recoil.

Traditional twist-in dovetail front rings and dual side-screw rear rings have just one advantage: You can use the rear ring to make massive windage adjustments if necessary. This is particularly helpful on old actions with off-center screw holes.

Aside from that, such rings are a pain. Twist in the front ring using a correct-fitting hardwood dowel. Getting it perfectly aligned with the barrel is difficult but important. Don’t back the ring up unless you have to, because this will loosen the friction fit between the base and the ring’s dovetail.

Set the rear, dual side-screw ring in place but leave the side screws loose. Don’t tighten them until you’ve laid the scope in the rings and confirmed that the front ring is holding the scope in alignment with the bore.

If crooked, remove the scope and use the dowel to make adjustments. Never use the scope itself to turn the front ring.

Snug up the rear dual side-screws and torque them gradually, back and forth, to spec.

Step 4: Lap the rings

Here’s the step that almost everybody should do and almost nobody does. Viewed as a custom gunsmith’s forte, lapping rings ensures that the inner surface of each ring is perfectly round, concentric, and aligned with its mate. Lapped rings hold scopes as securely as possible and don’t apply any consistency-robbing distortion to the scope tube. Lapping kits aren’t expensive, and you can order one from Brownells.

Apply a thin layer of fine lapping compound to the lap. Lay it in the rings, install the ring tops, and finger-snug the top screws. Mark each ring top so you can return it to the correct position.

Work the lap for about the duration of a tune on the radio. Remove the ring tops, clean up the inside surfaces of the rings, and examine your progress.

Refresh the compound and keep working until the inner surfaces show 80 percent or more bright polish inside the rings. It goes fast with aluminum rings, but steel takes longer. Clean everything up and apply a thin film of gun oil.

It’s worth noting that premium cross-slot-type rings machined from bar stock rarely need lapping. This is one of the significant benefits of top-end rings.

From this point forward, avoid removing the lower halves of the rings. Taking them off and on may introduce positional discrepancies.

Step 5: Level the crosshairs & install the ring tops

Lay your scope in the freshly lapped rings, loosely install the ring tops, and set eye relief by looking through the scope from various positions.

Level the crosshairs using a scope leveling kit by Wheeler Engineering or something similar. Apply a drop of blue LocTite to each screw and gently finger tighten them. Even up the gaps on each side between ring top and bottom. Alternating back and forth and maintaining the crosshairs in level position, gradually tighten the top ring screws to factory torque specs.

Assuming you’ve used quality components and the correct mounting technique, your scope is now as fail-proof as you can humanly make it. Horses and bad falls can still mess it up, but it’s got a better chance of surviving the everyday falls common to backcountry hunters.