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Proper Riflescope Mounting

Proper Riflescope Mounting

Improper mounting of riflescopes can account for an enormous majority of observed mechanical issues relating to the reticle’s responsiveness to turret manipulation, or “tracking”, as it’s referred to by professionals.  Improper mounting can also cause less-than-ideal movement of the magnification ring, and even image focus issues (parallax).

Many optic manufacturers stand behind their products with a solid warranty, like the Vortex Optics VIP Warranty.  But should you botch the mounting job badly enough to impact function, it would still be a pain in the rear to pull a scope back off, send it in, and wait for your repair or replacement to arrive.  If you’re relying on that optic for a fast-approaching hunt or competition, it’s well worth the small effort needed to set up your optic properly, to say the least. Here are a few tips and tricks to avoid the biggest pitfalls.

Buy good rings, or lap them

First and foremost, buy quality rings. Any time a rifle allows it, (based on whether or not a picatinny rail is to be used) I buy the Vortex Optics Precision Matched Rings

Buy quality scope rings when possible. When you can’t find a pair of rings that you trust to match your rifle, lap the rings.

Buy quality scope rings when possible. When you can’t find a pair of rings that you trust to match your rifle, lap the rings.

The need for quality rings became painfully evident for me just recently, when mounting a pair of (not naming names) ultralight rings to my father’s Browning X-Bolt.  For those unfamiliar with the X-Bolt, the rifle has a unique hole-pattern for the scope bases on the top of the receiver, limiting the user’s available options. 

I had to lap these rings with a special lapping kit for what seemed like ages, showing me just how far from true the rings were when installed.  The rear ring in-particular was out of alignment so badly that I had worn through the finish and well into the meat of the ring before it came anywhere close to being concentric to the front ring.  Not cool.

Had I just thrown the optic into the rings and tightened them down, the pressure exerted on the scope tube would likely have been uneven, potentially resulting in a laundry-list of mechanical issues.  In short, purchase quality rings, or at the very least, invest in a lapping kit, and use it religiously. There are only a few manufacturers who produce rings with a level of concentricity high enough to negate the need to lap.

It’s worth mentioning here that buying the lowest rings that your barrel contour and objective lens size will keep the optic lower to the receiver. While this seems obvious, a lower scope is an advantage on most hunting rifles, where comb height is not adjustable. Many of the sporter-type rifles make it difficult to achieve proper eye alignment while maintaining a solid cheek weld. To build up the comb height on my hunting rifles, I use a Triad Tactical Stock Pack.

Leveling your optic

During the scope mounting process, you must make sure that the optic and the rifle are level and square to each other. Start by finding a level spot on the action or the mounting rail on which to rest a bubble level. On some rifles, where flat surfaces are as scarce as an NRA member at a PETA rally, this can prove difficult.  In these situations, I mount a ring with the top-half removed, leveling off of the ring before the optic is set in place.

If your receiver does not have any flat areas to mount a level, attached the lower half of your rings and level off the top.

If your receiver does not have any flat areas to mount a level, attached the lower half of your rings and level off the top.

Once the rifle is level, it’s common practice to level the optic by putting a bubble level on the top turret or cap.  While this can and usually does work, not all optics are built to exacting external specifications, resulting in some wonky surfaces which may skew the accuracy of your level reading.  So here’s an alternative… 

Gravity doesn’t lie, so using a plumb-bob does wonders. Tie a piece of 550 cord to any heavy item, and hang it from a nail against a white wall.  Looking through the optic, align the vertical crosshair with the now-taut paracord.  Again, maintain a level rifle during this process. This will ensure the horizontal crosshair is exactly perpendicular to the drop of your bullet.  If the path of your projectile isn’t in line with the vertical crosshair, your point of impact won’t be where you’d expect.

With picatinny mount rings the slot on the rail will most likely be larger than the clamp bar running across the underside of the ring. Be sure that your rings are pushed forward, and the bar is making solid contact with the picatinny notch toward the bore of the rifle. This will ensure that there is no room for the ring to creep forward due to recoil.

Eye relief

As you mount your optic, be sure to check for proper eye relief.  Do so while the optic is at its highest magnification setting.  At low magnification, the eye box (the area behind the optic that provides a full field-of-view) will be very forgiving, and won’t accurately simulate field conditions when the optic is zoomed in further.

Ryan Muckenhirn, a Sales Associate at Vortex Optics, explained that setting eye relief is best done from the standing position, assuming the rifle could be fired from a number of different shooting positions.  Standing will provide a good “middle-of-the-road” between prone and seated shooting, as far as head-position is concerned.  If your eye is at the perfect distance from the optic while standing, it’ll be very close in other positions as well.

Because moving the optic forward and backward in the rings has major potential to throw off your level, this step is best done before leveling the optic, in the previously mentioned steps.  So, set your eye relief and mark it with a piece of tape placed on the scope tube before attempting to level the optic. 

Over-torquing rings

Over-torqued rings are likely the number one culprit of riflescope malfunction, and a crushed scope tube isn’t always evident without very close inspection.  Inappropriate tightening of a scope ring can apply extreme pressure to internal mechanical components, and cranking away with the long side of an allen-key like you’re tightening the lug nuts on a Mack truck is not advised.

Consider purchasing a quality inch-pound torque wrench and consult the manufacturer of your optic on the recommended torque specifications for your optic if it’s not published in the owner’s manual.

Ryan tells me there’s no need to exceed 18 inch-pounds on any scope ring, and 16 to 17 inch-pounds is more than sufficient for a lightweight optic, like the Vortex Razor HD LH (Light Hunter).  He also noted that, as would be expected, heavy-duty, tactical optics that have thicker main-tube walls than many hunting optics, and can handle torque levels on the higher end of the range.  I torque picatinny clamps to 40 inch-pounds. Avoid using thread-locking compound on the ring-screws.  It’s not necessary and can throw off your torque wrench reading. 

I’ve been guilty of over-tightening rings in the past.  I say over-tightening as opposed to under-tightening, as like most of us, I’m of the mindset that there’s no such thing as too dead, to tight, too fast or too much power, right?  Wrong.

I’ve had an inch-pound torque wrench for a while, but inevitably, the parts and pieces got lost, and eventually the wrench sprouted legs and walked off my workbench, so I picked up a new Vortex Torque Wrench Kit. The tool comes in a nifty, threaded tube that keeps all the parts in one place, as well as an assortment of drivers and bits that fit many common ring and base fasteners. The kit is fast, affordable and easy to use, and now everyone asks me to borrow it.  I’ll likely be purchasing them in bulk as Christmas presents this coming holiday season. 

The Vortex Torque Wrench Kit

The Vortex Torque Wrench Kit

When tightening your rings, do so evenly.  Make sure that each side of the ring shows an even gap between the top and bottom halves of the rings.  If the ring has two or more screws per side, keep the tension even on these while tightening (tighten in a crisscross pattern).  While this is best practice, it also keeps the optic from rolling in the loose ring, inducing reticle-cant.  Turn one screw a little, then go on to another, and go round and round until your torque wrench clicks.  Clickity click, you’re done. 

Torque ring screws in a crisscross pattern

Torque ring screws in a crisscross pattern

Feel free to check tension after shooting the rifle for the first time.  If a screw is going to loosen up, as unlikely as that is, it’ll probably do so on your first outing. 

And there you have it.  Follow these steps, buy a quality optic, and enjoy the highest level of accuracy that you, your rifle and your load are capable of.  Happy shooting. 

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Northern Alaska isn’t a good place to learn that your scope was not properly mounted.

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