Scope mounts are probably everyones least favourite subject. Unless you are Nerdy.. I am. I wrote a whole article on Torque settings entitled “Lets talk about Torque”. It surprised me that popular demand hasn’t prompted the sequel “Look who’s torqueing”.. Anyway I digress.. Scope mounts…. We all spend a hell of a lot of money on good optics. Most guys I meet in the Rifle world have between $1000 – $5000 sat on their rifle. We spend a lot of time considering optic preference but comparitively little on attaching it to the rifle.
If you need to learn about the size options on scope mounts then take a look back on the Beginners guide we published a couple of years ago. In this article we will look at type and brand.
If we go back 10 years most of the mounts seen at the range were the seperate rings. In simple terms we had two metal rings which would attach to the picatinny rail or whichever mount/rail fixing you had selected. I have used many brands of these rings. I had no major issues until I moved onto larger Calibers (300WM and upward). I started experiencing slippage and often the scope tubes would look scuffed in certain areas. I began wondering if the rings were achieving the best mating surface with the scope tube, the uneven scuffs suggested not.
To test this theory I aquired some callibrated lapping rods. For those that do not know these are basically rods which match the scope tube diameter. Each rod has a pointed end which when affixed into your rings should both meet at the points. In reality I discovered I had no rings which were in perfect alignment. Most were out by quite a margin – microns I can swallow but millimeters not so much. If the rings were out this much then tightening down on scope tubes would be applying pressure to them and cause a poor mating surface. I set about lapping the rings with abrasive polish. Time consuming. It worked though.
Forward to 2017.. Most of the mounts I see on scoped rifles now tend to be a one piece mount. The advent of affordable high end CNC machines has made the production of such items more precise and cost efficient. Although I found one piece mounts to be generally better in terms of precision I still had some issues. The 338LMs and .50BMGs I was shooting reguarly were pretty hard on the mounts in terms of recoil and I was back to Lapping to improve the mating surface of tube with ring.
I kept an eye on the market and eventually picked up a one piece mount from a relatively new company called Spuhr. The build quality was solid and the lapping rods showed the rings were pretty much dead on. My job involves the preparation and maintenance of small arms up to .50cal. The high muzzle energy rifles all got Spuhr mounts to cradle the fantastic Steiner M5Xi scopes. No more slipping under recoil.. Now all the work rifles I use have Spuhr mounts.
The mounts I selected were all Picatinny fitment. Spuhr also offer direct mount options for most popular rifles. Picatinny suits my needs as all of the systems at work come with Pic rails as standard.
The mounts are made from a block of 7075 Aluminium. This keeps the weight down but provides a rugged enough piece to deal with a few bumps in the field.
The rings have been drilled and tapped to allow additional accessories to be fitted. This includes a 45 degree position for those that want quick access back up sights
The rings are split diagonally and are held in place by six star head screws each. It is very easy to set up as you can just place the base on your picatinny rail and sit your optic in it. Then it’s just a case of moving the base and scope to suit your eye relief. The mounts come with a tool which enables you to level most optics to the mount. I say most because there are a few which the tool will not work with. I tend to use a plumb line at about 50yds and true the reticle to the line.
Once everything is in position I tighten the rings down to 25inch/pounds using a decent torque wrench. I go over all the fixings twice with the torque wrench to ensure consistent force is being applied. If some screws are tighter than others on any mount some of the screws will begin to loosen during repeated recoil. Consistent torque prevents that and negates the liberal application of blue loctite or worse people over tightening which can ruin your scope tube and mounts.
The last stage in scope mounting is to torque down the base to the rifles picatinny rail. Base screws are a lot more resillient and I normally aim for 50inch/pounds. I think that may be a little more than manufacturers recommendation but it works just fine and is the Mil Spec for torque on mount bases. One point to note with the Spuhr mounts is the four base screws which are numbered 1-4. The idea behind the numbers is that they should be tightened in order. I follow the manufacturers guidance on that and have always done it. When you tighten down, the head of the screw snugs down on a split ring which keeps everything tight.
Most people have little idea if their optic or mounting system is causing an error. This is probably due to the tests required to confirm function are a little bit dull! I have run tall target and box tests in the past. Both of these tests require a very accurate load and a high level of shooter/system accuracy but are about the only realistic way of testing if the optic set up is staying consistent. Saying that if you target shoot every week with the rifle your probably going to be able to see any errors as they happen. You might even feel them if the scope moves under recoil. I have had zero issues with the Spuhr after putting thousands of rounds of 338 and 50cal through them. They are not cheap so you do get what you pay for which is pretty much perfection.