How to Easily Mount a Scope

Shooter’s today enjoy a wealth of choices in optics. Everything from telescopes to red dot sights and holographics to night vision and thermal scopes. More than any other time in history there is a scope for every need and almost any budget. From the simple crosshair 10x scope to the most cutting edge thermal-night vision, if you can think of it, you can find it.

But getting even the very best scope does no good if you don’t mount it and mount it correctly!

optics on rifle

While the proliferation of easy-on easy-off throw lever mounts and other peculiar mounting systems has made popping on a new optic relatively idiot proof and hassle-free, there are times where you’ll need to break out the tools, apply a little elbow grease and put on your thinking cap to make sure your optic is mounted true and proper so you can sight through it easily.

In this article, I’ll dig into my bag of tricks and share with you how to properly install a variety of optics on various guns easily and correctly.

The Importance of Proper Mounting

A cheap scope may never be worth a cuss no matter how well you mount it and that sucks, but it is truly a tragedy to see a quality optic fail you because it was mounted incorrectly or with substandard rings or bases.

You might get lucky if you hope for the best and just clamp ‘er down as hard as you can, but you stand just as good a chance of botching the job as anything else. Why risk damaging the one piece of equipment that will routinely cost more than the gun itself?

Your scope and its mounts are a system, meaning they are parts that work in harmony to produce a result. Your optical system in toto with the gun is another system, and they must work together with you to precisely deliver a projectile to a specific point.

A botched installation can result in an optic that will not properly zero to the gun, or one that will lose its zero at an inopportune time from handling or shooting. If any part of the system breaks down, the system degrades or fails.

That means misses or poor hits. Poor hits and misses mean lost game, lost matches, or lost opportunities to solve a bipedal problem from a position of advantage.

I am continually amazed and shocked by how much folks will spend on a scope or dig into the minutiae of precision shooting only to turn right around and flop on the price of rings and then wing it on the install.

Don’t you want to be a complete “systems provider” for your guns, or your survival group’s guns? You should! So take optic mounting as seriously as reloading or marksmanship and tactical training.

Yeah, yeah, it isn’t as cool or fun, but you want to know what’s really cool?

Competency!

The Importance of Quality Mounts

Whatever type of scope you are installing, the mounts, be they standard rings, proprietary clamping bases or quick-detach whatchamacallits, are just as important as the scope itself in ensuring you get on target, perhaps even more so! A modest scope in very high quality rings will be more consistent that a top-tier scope in hobby-grade rings.

If you cannot afford to spend on rings that are commensurate or of better grade than your optic’s quality, you should clutch in and go down a peg on your scope so you can. I am not fooling around here! It is that important.

Think about it: the mounts mate the optic to the firearm. Not only must they be able to properly fit and grip both scope and gun, but they must also be true to the mounting platform or else you will be losing your adjustment range made possible by the optic and perhaps even unable to adjust the scope to coincide with desired point of impact entirely!

On top of it all, the mounts must be able to survive constant, severe vibration and potentially abusive shocks from drops, slams, bangs, dings and dents. That’s no small order for such a small thing.

Like the guns themselves and most scopes, you do get what you pay for. Remember that!

Types of Mounts

Your mounts will fall into two big categories for most guns today, and are then further broken down into families based on the type of, well, base that they mate to.

Your standard telescopic sight, or “scope” as typically seen on hunting rifles, sniper rifles and an increasing number of black guns thanks to the popularity of LPVOs, will accept standard rings, which are two separate rings with screw-down attachment points or possibly quick release throw levers or knobs, or one piece rings where rings are machined into an attachment point together and the entire assembly clamps down on the gun.

Both work but the one piece mounts are, as a rule, superior since they reduce more variables in mounting geometry and are typically a “truer” mounting solution than the old standby of standard rings.

That being said, for “sporter” style guns and hunting rifles it is usually easier to get the scope a little lower using standard rings. More on that in just a bit, hold that thought!

The other pertinent factor for determining which mounts/rings you should buy is what kind of base they attach to. Today, the Mil-STD. 1913 rail or Picatinny rail is the overwhelming standard and you’ll see these cheese grater looking rails adorning everything from handguns to rifles and shotguns of all kinds.

They of course feature prominently on nearly every AR and black rifle, too. If in doubt, just look for the word ‘1913” or “Picatinny” on the package to confirm compatibility.

A close cousin to the above is a Weaver rail, which looks similar but only has one or a few slots in each end to accept the crossbar of the mount. The specific dimensions of the bases do differ, but are close enough to usually allow you to make one work on the other in a pinch.

The great perk of using such a common and ubiquitous base is that you’ll have no issue moving an optic and its mount from gun to gun if you want to, and they allow a great degree of fine adjustment fore and aft when you are placing the scope. This is huge for getting the proper eye relief on a magnified optic or balancing the gun and maximizing field of view in the case of a red dot.

But a “Pic” rail is not the only game in town. Plenty of older hunting rifles and even some modern ones used specialized bases cut to accept proprietary nubs and tabs machined into the bottom of a mount or base.

These guns often have their corresponding rings or mounts for a variety of optics available from the manufacturer or even included with the gun. If you have a gun like this and just cannot seem to find the mating rings take heart that you can often get an adapter base that will convert it to, yup, a good old Pic rail.

Do note that such solutions do add height to your mounting solution and that can be a detriment sometimes. Generally lower is better when it comes it mounting height.

scope diagram

Getting the Scope on the Gun

I’ll offer a couple of examples for mounting both a traditional rings and unibody one-piece bases in this section with a few tips and tricks I learned along the way thrown in.

The process is similar, but standard rings mounting a telescope will have more steps to ensure a proper install. You’ll need a few odd tools which I have listed below.

Helpful Tools for Mounting Scopes

  • Complete set of hex keys and gunsmith screwdrivers
    • Hex bolts are very common across several generations of mounts and bases, as are slotted and occasionally Phillips fasteners. Torx or “star” drive fasters are also common on high-grade mounts and bases, so grab the most common small sizes while you are at it.
  • Torque Wrench/Driver
    • By far the most overlooked facet of assembling guns, to include installing scopes, is the tightening of all fasteners to the factory prescribed level of torque. For most home installers, the only levels of tightness are “entirely too tight” and “not nearly tight enough.” Neither is good as one will possibly damage your fasteners, mount or optic and the other will let the former let go of the latter. The only way to do so accurately is with a torque measuring wrench or driver for the purpose. These are precision tools and expensive, but there is nothing else that will do what they do.
  • Gun Vise
    • This simple table or benchtop rig holds a gun in an upright and reasonably level position, allowing you to install and if necessary level your optic with ease. An alternate method for AR’s is to use a magwell jig and clamp that into a standard work vise.
  • Levels or Scope Leveling Tool
    • You’ll need a pair of accurate small beam levels, no more than 6 inches long or so, to establish your baseline for your gun and then match the scope to it. A crooked scope is a bear to zero and means you will be missing more than you are hitting. This is only necessary with scopes that can turn freely in their rings; optics with built-in bases or ones “keyed” into their mounts are exempt from this.
    • If you do a lot of playing around with telescopes, you might consider picking up a scope leveling toolkit from Brownells or another vendor. This can do the job more precisely than a pair of beam levels.
  • Collimator
    • A collimator is a tool you stick in the bore of the gun that holds up a reference grid showing you where “straight ahead” is in relation to the bore line. This is useful for getting a quick coarse zero beyond dead center when you install your scope. To use it, you’ll simply look through your optic and use the adjustments to align the reticle with the prescribed indicator on the collimator. Not strictly necessary, but can save you time, ammo and frustration when the time comes to zero the gun to the optic.
  • Thread Locking Compound
    • Vibration is the enemy of a good mounting job. When screws come loose, things start moving. When things start moving when they shouldn’t you lose your zero. Not good, sir. To ensure those screws stay as snug as you left them, use thread locker! Generally, a tiny drop of non-permanent compound will work wonders with proper torque to keep your mounts and scope dead-nuts tight. Using permanent or semi-permanent locker could mean destruction of your mounts or fasteners in order to get it back off.
  • Paint Pen
    • Sharpie makes good ones. Use this to place witness marks on your fasteners so you can tell if they are loosening after you have them properly installed and torqued down.

That’s it for the shopping list. In a pinch, you can get by with just the drivers and wrenches, the levels (for a telescope) and the paint pen.

leveling a rifle scope

Installation Guides

The following guide is a step by step how-to to installing a variety of optics. You’ll not that modern keyed mounts with QD attachments dramatically simplify this process. If you can afford them and your mounting problem will allow them, I highly recommend you spring for them. The time you’ll save not to mention the wear and tear on your sanity is significant.

No matter the install, begin with your firearm dogged in the bench vise. Then, determine what kind of mount you have and how the optic interacts with it.

If Your Optic Does NOT Rotate in the Mount and the Mount has Q.D. levers or knobs

  1. Determine proper eye relief for optic (if magnified) or best position for balance/field of view if non-magnified.
  2. Open fasteners on mount; swing open levers, unscrew knobs, etc.
  3. Place mount in position.
  4. Close/tighten fasteners.

That’s it! What could be simpler! You can run into issues with pre-set QD mounts’ fasteners from time to time. Due to the huge variation in manufacturers’ specs on what should be precisely machined bases (Pic rails are notorious offenders) you will sometimes find that your levers will not close, even with great force applied.

Take care! An overlarge rail might mean crush damage from your mount. Instead of Hulking the levers closed, consult your manual for the mount itself; most have instructions for slightly adjusting the tension for just such an occasion.

Note that “grabber” bolts, as exemplified by the self torquing knob on Aimpoint’s factory PRO and Comp series mounts are far more generously forgiving of such variances that throw-lever mounts. Something to think about!

If Your Optic DOES Rotate in the Mount and the Mount has Q.D. levers or knobs

  1. Level gun in vise by placing level across mounting base or flat top of receiver.
  2. Determine proper eye relief for optic (if magnified) or best position for balance/field of view if non-magnified.
  3. Open fasteners on mount; swing open levers, unscrew knobs, etc.
  4. Place mount in position.
  5. Close/tighten fasteners.
  6. Remove top half of rings, set aside.
  7. Place optic in mount. Double check eye-relief and height.
  8. Level optic by placing level across flat upper area on optic; use turrets or turret caps if necessary.
  9. Once optic is level, carefully set ring halves in position.
  10. Place dab of thread locker on end of fasteners.
  11. Without disturbing optic, tighten fasteners evenly across all rings until just barely snug.
  12. Taking care to tighten each fastener so as to maintain even pressure on optic, tighten all fasteners to manufacturer recommended torque.

As you can see, standard scope in rings of any kind take a fair bit more work and care to ensure a good, proper installation.

If Your Optic Requires Separate Traditional Rings

  1. Level gun in vise by placing level across mounting base or flat top of receiver.
  2. Determine proper eye relief for optic (if magnified) or best position for balance/field of view if non-magnified.
  3. Remove top half of rings, set aside.
  4. Install rings; hand snug fasteners only.
  5. Set scope in rings; adjust to check height and eye-relief with ring position. If OK, proceed.
  6. Remove rings from gun; add drop of thread locker on ring fasteners and reinstall rings.
  7. Tighten ring fasteners to base using manufacturer recommended torque.
  8. Place optic in mount. Double check eye-relief and height.
  9. Level optic by placing level across flat upper area on optic; use turrets or turret caps if necessary.
  10. Once optic is level, carefully set ring halves in position.
  11. Place dab of thread locker on end of fasteners.
  12. Without disturbing optic, tighten fasteners evenly across all rings until just barely snug.
  13. Taking care to tighten each fastener so as to maintain even pressure on optic, tighten all fasteners to manufacturer recommended torque.

Traditional rings can take the most work of all. Variances in tolerances between two separate clamping surfaces can induce stress and strain on optics and even affect accuracy.

This can be overcome by truing and lapping the interior surfaces of the rings but such an operation is beyond the scope (heh) of this humble guide!

Tom’s Tips

If there is one thing that is sure to drive any shooter crazy, it is the quest to find just the right rings or mounts. Depending on your base firearm, stock variations or modifications, peculiars of your scope and your own anatomy, getting a scope in just the right position for comfortable and efficient shooting can feel like a rigged game.

This is exacerbated when your bases only allow one or two positions for installing the mounts; if those don’t work, you can feel screwed indeed! Boy, it sure is nice having those Pic rails all over more modern black rifles, huh? Plenty of adjustability!

In the case that you cannot seem to suss all of this out, start with the essential characteristics you are dealing with and then go from there. Armed with the right info, you can help a gun shop or parts supplier zero you in on the rings you need to get your optic mounted and zeroed.

The first precept: the lower your scope is mounted to the bore/receiver, the better, unless your stock/cheek rest is so tall that you can no longer get behind and in line with the eyepiece.

Second, always, always, always know the diameter, the actual diameter of your objective lens. That’s the big bell shaped front lens of the scope. The wider it is, the taller your rings will need to be to accommodate it.

Taller rings means greater mechanical offset from the receiver and you’ll probably need to add a riser or pad to the comb of your stock to help out.

Your next major hurdle is eye relief. Eye relief is the distance from the eyepiece that your pupil needs to be to make the image you see through the scope “whole,” or fill the tube. Some scopes will have you be closer, others are more generous and allow you to be farther.

If you rings will not allow you to move the scope far enough forward or backward to allow proper eye relief, you’ll need to do one of two things:

First Option: Install an extended base if possible, one that will also afford you better granularity in installing the rings to begin with. Take care, as almost all adapter bases add a little extra height compared to direct mounted rings.

Second Option: Purchase cantilever rings, sometimes called gooseneck or slantback rings. These rings seem stretched in one direction or another, in essence moving the “bottom out” point farther forward or backward to shift the acceptable range where you can position the scope without repositioning the rings.

But hopefully you won’t run into any eye relief or scope height issues and you’ll make short work of your scope installation with my handy guide!

Conclusion

Installing a scope can be a piece of cake or an expedition into the very heart of frustration. Even with the availability or click-it-and-forget-it mounts today it pays to know how to install a classic telescope using rings the right way, as these mounts are going nowhere for the foreseeable future and it pays to be prepared as a prepper.

No matter which type of mounts and optics you choose for yourself, give your optic installation the care and attention it deserves so you can have confidence when it is time to shoot.

mounting a scope Pinterest image

About Tom Marlowe

Tom Marlowe
Tom Marlowe practically grew up with a gun in his hand, and has held all kinds of jobs in the gun industry: range safety, sales, instruction and consulting, Tom has the experience to help civilian shooters figure out what will work best for them.

Leave a Reply

Your email address will not be published. Required fields are marked *