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If you choose to mount a rifle scope yourself, you will need a a gun vise and a clean, well-lit area. Once you're prepared, start by removing any filler screws in the top of your receiver with a properly fitted screwdriver and then degrease the holes. However, if you have a grooved receiver or an integral Weaver/Picatinny base, skip this step. Degrease all mount parts, then reapply a light coat of oil to the top of the receiver and the bottoms of the bases or rings.
After preparing the rifle, check the instructions for your particular mounting system. Some manufacturers that use Torx screws suggest a light coat of oil on the screw threads. I normally use Loctite on all base screws, but you should never use it on ring screws. Always apply to the screws, not in the threaded holes. Some bases will have screws of different lengths. Check them first visually. Make sure the screws are in the correct places. Screw threads should protrude about the same amount from the underside of the bases. Putting too-short screws in the wrong places can result in a scope being torn off by recoil or handling, and screws that are too long can bind a bolt or result in a loose base. Install the bases using Loctite or gun oil, depending on what the manufacturer suggests. Tighten securely.
How Do You Install the Rings?
Next, install the bottom half of the rings onto the bases. If you have a Weaver or Picatinny system you may tighten them securely with a properly sized screwdriver or wrench. If you have a Leupold turn-in style you will need to assemble the top half of the ring onto the bottom ring, place it in the base, and use a wooden dowel or non-marring screwdriver handle to turn the ring 90 degrees. This is a press fit and cannot be done by hand. Do not remove the factory-applied grease on the mating parts. Every time a Leupold system is installed it gets a little looser. Reapply grease if needed. A Leupold ring wrench is worth its weight in gold for installing rings.
If using a dual dovetail system, repeat this procedure for the rear ring. The adjustable rear base on a standard Leupold system has two opposing screws that allow for significant windage adjustments. Center the ring onto the base by eye and snug the opposing screws.
How Can I Adjust the Scope and Rings?
This is the time to use a scope ring alignment tool if you have one. Those sold by Wheeler Engineering are excellent, and prevent damaged scope tubes caused by misaligned rings. These tools are two-piece rods that are either 1 inch or 30mm. Each one has a pointed end. Install the alignment tool between the ring halves and move the front and rear rings using the alignment tool until the pointed tips of the tool are almost touching.
Remove the top halves of the rings and place your scope in the bottom ring halves. The scope should fall to the bottom of both rings. You can lightly install your top ring halves.
How Do You Sight in a Rifle Scope?
Remove the bolt of your rifle if possible and look through the bore at a target placed at least 25 yards away. Adjust the rifle scope so that the crosshairs point at the same place you see when looking through your barrel. You can also use a boresighter to make this process easier. Results are about the same with any type of boresighting. Remember, boresighting will simply get your shots on paper at shorter distances so you can sight in by actually shooting at a certain distance with a certain load. No boresighter can sight in a gun. Period.
What Windage and Elevation Adjustments Should I Make?
If you can easily adjust your scope when boresighting to approximate center without significant manipulation of the windage and elevation knobs on your scope, you are ready for the next step. However, if the windage is off a lot and you have standard Leupold-type bases with windage screws, take the rifle scope back out before you move the bases accordingly so that you don't misalign the rings and damage the rifle scope. Move the rear base and realign both rings with an alignment tool or place the rifle scope back in the bottom ring halves and ensure the scope drops to the bottom again. Lightly install the top halves of your rings and check the boresight again. With dual dovetail systems you have no option for base adjustments, so if your adjustments are at their maximum, switch to a base with windage screws. If you have a Weaver or Picatinny rail system and your windage is off, some manufacturers, like Millett, offer rings that are windage adjustable. If elevation is an issue with any system you may have to place a shim under your front or rear base, or get a base with built-in elevation.
If you don't have a boresight or alignment tool just do the best you can by eye. You can use a 1" or 30mm bar or an old scope that you won't mind a scratch or two on to see if it falls to the bottom of the rings. I still sometimes use a piece of an old Harley handlebar that measures .9997 and is perfect.
What Is Lapping?
If your boresight looks good, you may now lap the rings. Lapping polishes the inside of your rings. Lapping tools are available from Wheeler Engineering and they ensure maximum scope to scope ring contact and remove sharp edges on rings that can scratch scopes. Instructions are provided with these lapping tools. The Tipton gun vises and the Wheeler Engineering screwdrivers, alignment tools, and lapping bars are an important part of any firearm workspace and are inexpensive investments that will last a lifetime.
If you have lapped your rings, remove all traces of the abrasive lapping compound with a solvent, then degrease with a moistened patch. Place your scope in the bottom half of your rings and loosely install the top ring halves. With your scope at its highest magnification, aim the scope at a bare wall some distance away or at the sky, and adjust the eye relief. To do this, move the scope gently fore and aft until you get the maximum distance the scope can be from your eye and still give you a full sight picture. At lower magnification you generally have more eye relief available, so remember to set the placement of your scope when it's at its highest magnification.
Final Adjustments
This is also the time to level your crosshairs. Again, Wheeler Engineering sells a neat leveling product that rests on your gun and your scope that takes the guesswork out of this procedure. Doing this by eye is more difficult, as you'll often have to loosen your ring screws to re-level several times until you're satisfied that the reticle is straight. Tightening the ring screws also moves the rifle scope slightly one way or another. Tighten the top half of the ring screws evenly from one side to the other, just a bit at a time and always from one side to the other, trying to keep the gap between the rings even. There will be a gap. Tighten the ring screws securely, but don't try to tighten the screws enough to close this gap.
With your scope now securely mounted, check the function of the rifle to make sure the action is not bound by too-long base screws and that the ocular bell does not interfere with the manipulation of your bolt on a bolt action rifle.
Boresight your gun and shoot! Check the tightness of your ring screws occasionally. Have fun!
