Guide to Lapping Scope Rings
VIDEO GUIDE AVAILABLE BELOW!
The world of precision marksmanship hinges on one watchword: consistency. The more you and your tools – rifle, scope, ammunition, etc. –perform, the more accurate you are. Consistency in equipment is achieved by removing variables. When the gun is rock solid, each round of ammunition is identical, and the shooter is doing his part the only variables you have to concern yourself with are the environmental factors: range, windage, elevation, temperature, and such.
One way to remove yet one more variable from your equipment is to lap your scope rings. We will get into the benefits of lapping scope rings a little further down, but it gives your scope a better, more solid mount, reduces stress on the optic, and relieves stress on the action, all good things when surgical precision is the goal. Let’s get into lapping, starting with what it is and what it does. We’ll then get into how it’s done.
Lapping Scope Rings: What it is + What it Does
Though more and more shooters are realizing the importance of high-quality scope rings they are still perhaps the most overlooked component of a precision rifle system. Most of us think of the rifle first, the glass second, ammunition third, then “everything else” last. Everything else includes a host of stuff like bipods, oversized bolt handles, suppressors, and yes, scope rings. Scope rings are incredibly important, though; they literally hold the aiming system to the rifle. Without a solid mount the scope may move which can alter your zero.
One way to improve your scope rings is by lapping them. Lapping is the process of truing the inside surface of your scope rings, evening out high and low spots. This gives the scope ring a uniform, consistent fit across its entire surface, increasing engagement with the scope tube. This is achieved by what amounts to carefully sanding the inside surface of the scope rings. What are the benefits of lapping scope rings?
First, lapping scope rings protects the scope. It’s a common saying that you should spend at least as much on glass as you spent on the rifle. If you do, that’s a pretty big investment and you want to protect it. The insides of scope rings can have imperfections – high spots and low spots. When the scope is placed in imperfect rings, the high spots can dig into the scope, damaging its finish and possibly even denting the tube, albeit very slightly.
Having an even engagement surface between rings and tubes also decreases stress on the scope tube. This means your view is truer, and your adjustments are truer and less stress is placed on the inner gears of the scope that move your reticle. Lapping your scope rings also provides a more secure fit for the scope. If the fitment is not perfect the scope can move under repeated recoil, forward and/or backward, and it can potentially rotate side to side. This makes adjustments imprecise and makes predicting their impact difficult if not impossible.
Lapping your scope rings can also improve accuracy by reducing stress on the action. Scope rings mount to the action. When a scope is placed into the rings and the alignment is imperfect, it can push or pull the rings in opposite directions. This places stress on the action, which slightly alters its alignment with the rifle’s bore. Obviously, all of these are all undesirable and have a potentially huge combined negative impact on accuracy.
How to Lap Scope Rings
You will need a few very specialized tools for lapping scope rings. The Wheeler Professional Scope Mounting Kit sold by Red Hawk Rifles contains everything you need to get the job done: lapping compound, and a lapping bar with handle. You will also need a bit to remove and tighten the scope rings, and a bit of tape and a sharpie for marking the rings. Once you have gathered your tools, mount your rifle in a firm work surface.
Next, ensure your scope rings are firmly mounted to the rifle. Before lapping you want to make sure the rings are where you want them. This requires some preparation on your part to ensure that the rings are in the appropriate position to put the scope where you want it for correct eye relief. Before proceeding double check and ensure the rings are securely mounted and that they are aligned correctly by inserting the alignment bars into the rings. The pointy tips of the alignment bars should meet each other in the middle. This isn’t likely to be a problem with modern scope rings but it’s worth checking before making inalterable changes to your scope rings.
Once the rings are securely mounted and aligned, remove the top halves of the rings. Mark them “front” and “rear,” along with an arrow indicating which way is forward. Once the rings are lapped they are mated to that lower half of the ring, and should always be installed in the correct orientation. They cannot get mixed up, nor do you want to mount them backwards or they will no longer provide a perfect fit.
Now wipe a thin, even layer of lapping compound inside both the upper and lower halves of the rings. This gritty compound will lightly sand the insides of the rings. Place the lapping bar into the rings, and place the top halves of the rings over it, in the correct orientation. Replace the screws and tighten then until the lapping bar will move but is creating some friction.
At this point the lapping begins. Turn the rod, and move it back and forth. This begins to sand down the high spots, and you will notice a big change early in the process as high spots are removed. If the lapping rod feels too loose in the rings, tightly them down slightly again until the rod is making appropriate contact, and repeat. After 3-4 minutes you will have to remove the top halves of the rings and freshen up the lapping compound.
Before adding more lapping compound, wipe the old compound out of the bottom halves to check your progress. This process will likely have to be repeated several times. Aluminum rings are softer than steel and will lap faster and may be finished in just a couple of reps. Steel rings may require as many as five repetitions, and with each successive repetition you will tighten the rings slightly more. As you check your progress you want to stop when 75% or so of the bottom halves have been polished. It is possible to overdo it; if you remove too much material the rings will no longer have enough to achieve a solid grip on the tube.
Mounting The Scope in Lapped Rings
When you are finished lapping, clean the lapping compound of out of the rings completely. Make sure none is left behind as it can certainly scratch your scope’s finish. At this point the scope/ring fitment should feel different. There should be a smooth fit with the rings, with no rough spots and no misalignment. Lay the top halves of the rings over the scope and begin tightening the screws. Ensuring your rifle is level, level the scope with the levels included in the kit (leveling a scope is a whole ‘nother topic).
The ring screws should all tighten smoothly and all at once. When the rings are in proper alignment one side or one screw shouldn’t begin binding before another, the mark of a good lapping job. Tighten the screws fully, in the correct order and to the correct torque
At this point you have a scope mounted in lapped rings. It is in alignment and not placed under any unnecessary or unintended stress. Everything in the scope – it’s zoom and reticle mechanisms – can more freely without stress. The rifle’s action is truer because it, too, is under less stress. This places the action in more perfect alignment with the bore, allows to bolt to work more smoothly, and permits greater potential accuracy out of the system.
Once your scope is zeroed you can rest assured that your zero is correct, consistent, and repeatable, taking all the variables out of the rifle. This frees you up to worry about the variables you can control, like your own skill, and some you can’t like the environment.
Red Hawk Rifles — Your One Stop Shop to Rifle Upgrades
Red Hawk Rifles carries everything you need for mounting a scope, including rings, complete installation kits, and the optics themselves. For that matter, we have everything you need to build a complete rifle, including actions and chassis, trigger assemblies, barrels and muzzle devices, and bottom metal and magazines. And if you don’t want to build a rifle, we offer complete rifles, though you’ll still need to lap the scope rings you attach to them! If you’re in the market for a precision rifle, building your own from parts, or maintaining the one you have, Red Hawk Rifles is your one-stop-shop!