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Scope ring series: Part 4

Part 1
Part 2
Part 3

This report covers:

  • What have we learned?
  • Today
  • And the rings?
  • The objective side of the scope
  • The deal
  • Summary

Today we take our fourth and probably last look at scope rings. The previous report was on November 3, 2022.

What have we learned?

In this series we have examined the history of the rifle scope and the rings/mounts that it used. We learned that the first scope mounts are still with us today in essence, but in updated form. We learned that many older scopes were adjusted by their mounts alone; they didn’t have internal adjustments. But when erector tubes were put inside scope tubes the reticle adjustments became internal.

We learned that scope reticles were originally made from spider silk and then in the 1930s steel wire was used in scopes used on rifles that recoiled softly, because steel wire couldn’t take the recoil of powerful centerfire rifles. Spider silk is five times stronger than steel on a weight-for-weight basis and it can be stretched up to five times its length before breaking, making it nearly ideal for use in scopes. But when the erector tube came along, so did steel wire reticles.

We learned that a centered reticle didn’t come into being until 1956, when Weaver brought it out. Before that the elevation reticle (the horizontal reticle) moved up and down as adjustments were made.

We learned that the barrels on ALL rifles point down (have droop). That’s all firearms and all air rifles, with the AR-15 platform being the most droopy of the firearms, in general, and Diana breakbarrels being the most droopy of the air rifles, in general.

With firearms the amount of droop doesn’t usually affect things because it’s only inches at 100 yards and can be dealt with by the scope’s adjustments. But airguns shoot at closer distances and the amount of droop stands out. There are exceptions to this rule, but they stand out because they are exceptions. 

We learned about Weaver bases that were probably the father of the Mil Std.1913 Picatinny scope base. Those bases drove the development of the mounts/rings that fit on them.

We spent a lot of time discussing scope ring height and what it does and does not do. It has little to do with accuracy, but a lot to do with the scope’s zero as the distance to the target increases and decreases.

We learned that scope height is affected by the design of the rifle ands that some rifles need clearance for certain things. On airguns it’s mostly for clearance of those spring-loaded circular magazines.

Scope height also affects cant, which is when you tip the rifle to one side or the other. I won’t discuss cant in this series, but you can read about it in this 2019 report titled, What cant does.

Today

Whew! That’s a lot of stuff and leaves us just one more topic to cover. Let’s talk about scope placement on the air rifle. This is a big one.

At the rear of the scope the eyepiece has both an “exit pupil” and eye relief. The exit pupil is the width of the image exiting the scope’s eyepiece and the eye relief is the distance at which the entire image can be seen. The exit pupil determines the brightness of the image; the eye relief determines the distance at which the full image can be seen.

On some scopes the exit pupil appears as an image that is surrounded by the outside of the scope tube. I have also seen some scopes where, when you saw the image, you didn’t see any of the scope. These are lower-powered scopes that are ideal for hunting large game in the woods.

Back your sighting eye up or move it forward and you see less of the image. This is the effect of eye relief. You can still see the target and hit it if the image isn’t full, but the best place for your eye is where the entire image is visible and also where it is the brightest, if you can control that.

Generally as the scope’s magnification increases the length of the eye relief decreases. And the width of the exit pupil is similarly affected by magnification. I have seen some high-power scopes where everything is dark until your eye gets to the exact spot where the exit pupil is, both forward and back, which is far shorter than a half inch long and so narrow side-to-side that the stock has to fit your face perfectly or you won’t seen an image at all. Those scopes are too bothersome for me, but I note that champions use them a lot. I’m just saying.

And the rings?

What have the exit pupil and eye relief to do with the scope rings? Everything, as it turns out. Because some scopes don’t allow you to mount their eyepiece close enough to the buttstock for your eye to acquire the entire image. This is where cantilevered rings come into play — as long as the rifle has clearance for them with things like the safety or the bolt.

Better still are those scopes with long eye relief. When most scopes have an eye relief in the 2.5 to 3-inch range, there are scopes where it is 3 to 4.5 inches and longer. Some scout scopes are purposely designed for an eye relief in the 9- to 11-inches range. That’s the case for that scope on the Mosin Nagant I showed you in Part 3.

Tom shoots Mosin
See how far back and high my head has to be to see through that Mosin scope?

The Russians did not design the Mosin to be scoped. They designed it to accommodate the many different ethnic groups found in the Russian Army. One consequence of that is the buttstock drops more than any western military rifle. That exacerbates the high scope problem.

The Soviets solved the bolt issue for their sniper rifles by lowering the bolt handle. That allowed the scope to be mounted farther back and closer to the shooter’s eye.

sniper Mosin
This Hungarian Mosin sniper rifle has a lowered bolt handle so the 3.5-power sniper scope can be set back above the receiver. But nothing was done to elevate the shooter’s eye. I’m guessing there were field fixes such as stuffed socks tied around the buttstock.

The objective side of the scope

When you buy a scope, don’t overlook the fact that, if you are mounting it on a breakbarrel, the front objective lens and bell have to clear the breech when the barrel breaks open. If you are mounting the scope on an underlever or sidelever with a sliding compresion chamber you need to consider the clearance either ahead of or under the objective lens for loading a pellet. And on rifles that are taploaders there is the access to the tap to be considered.

Build a Custom Airgun

The deal

So, when you choose a scope and rings for a rifle you need to factor in where the eyepiece will be (can possibly be?) when the scope is mounted. If you don’t, or even can’t do that, you’ll have to solve the problem like a giraffe. This is why I preach on using two-piece rings — because they give you more latitude when positioning the scope. And don’t overlook the front end of the scope, because there can be problems there, as well.

Summary

I think that is it for scope rings. There are other things that will crop up in future reports, but they aren’t general to all scope rings. They are specific to either a set of rings or to the scope base on the rifle to which they are attached.

28 thoughts on “Scope ring series: Part 4”

  1. Tom,

    Something is tickling my brain in Section What have we learned? 2nd paragraph 1st sentence: “We learned that scope reticles were originally made from spider silk and then in the 1930s steel wire was used in scopes used on rifles that recoiled softly, because steel wire couldn’t take the recoil of powerful centerfire rifles.” Seems like you need to insert a sentence explaining why in volume production the relatively fragile steel wire replaced the expensive spider silk.

    When did etched glass for the reticles start being used?

    Siraniko

    • Siraniko,

      I wanted so much to talk about etched glass reticles, illuminated reticles, but this was a series about scope rings. Please keep after me and I will cover them, soon.

      BB

  2. Tom, I wonder if it was really necessary the long “what have we learned” section. This, along with the “Nagant” story and pictures were half of today’s blog… We can easily go back using your guide to the previous ones.
    Just friendly morning conversation, a little grungy because of some light flu.
    A very good day for you and everyone.

    • Bill,

      I just put the real summary at the beginning instead of the end. I know it was long but there was a lot of important stuff and so often I get asked questions that I have answered in earlier sections that I wanted to cover it again.

      BB

      • BB and Bill

        Actually, I liked having the summary up front. For two reasons,, my memory often lags a bit, and second,, I am also too lazy to go back to the other episodes to find these salient parts.

        I’m not sure how much more could have been wrung from rings, anyway. and I , too, will be anticipating the post on reticles, etched or otherwise.
        Ed

  3. BB,

    I wonder why it is that all rifles droop… Are they designed with ideal properties (infinite stiffness) in mind when actual steel has some elasticity?

    But anyway, from my (limited) experience, the assumption that everything droops seems to work well. When we mounted the scope on my friend’s Twenty-One, he was surprised that I put a shim on the rear mount. I just explained the concept of “droop” and said “trust me, this is a good idea 99% of the time” 🙂

    If in doubt, it’s probably better to have more pressure on the erector tube spring than less.

    I can even move my scope from the FWB300’s to the Diana 34s and the scope doesn’t require a ton of adjustment. Either our Dianas don’t droop *that* much, or the FWBs droop a little, too.

    Stephan

      • The Cpt beat me to the question. Why is it that most if not all rifle barrels droop? Is there a manufacturing reason? A safety reason? A practical reason? Perhaps a word from Ed Schultz 0r another mechanical/design engineer in the airgun or firearms industry could enlighten us?

        Fred formerly of the Demokratik Peeples Republik of NJ now happily in GA

        • Fred, just an unsubstantiated WAG: it could be to account for manufacturing tolerances. With open sights in a ‘drooper’ gun generally there is enough adjustment elevating the rear sight to obtain the proper alignment. On the on the other hand, in a gun that shoots too high the rear sight cannot be moved lower than zero so the only remedies are shortening the front post – ugly – or bending the barrel.
          Once again, this is only a product of my imagination and could be dead wrong.
          Henry

          • Henry TX: Your consideration, here, makes a good deal of sense. I’ve had to grind a front post and it was never satisfactory nor very accurate. RWS/Diana with the new Model 34 has a shim system that is supposed to relieve the droop issue. It will be interesting to see how this portends as it is, in fact used.

            As a springer devotee, I have been dealing with droop issues since 1989 and have gotten fairly proficient in shimming the rear of the scopes BEFORE using the turrets at all. The care has to be, then, to be extremely judicious about scope ring cap tightening, obviously since the axis of the scope tube is no longer in parallel with the axis of the rings. Crimping of the thin aluminum tube is an ever-present risk

            While I have no solution for this problem in my springers related to barrel alignment to eliminate droop, by shimming to the black BEFORE turning a scope turret seems to work. However, mention has been made of some adjustable (old school?) rings.

            BB, if there are adjustable scope rings available in the marketplace, maybe a fifth scope ring article is in order? I have often though that is the rings could be adjustable while avoiding slop in the hinging points, that mounting a scope would be so much easier and result is less potential damage to the scope tube. Are there any adjustable airgun available scope rings. If so, how well to they work and do they keep their “set” when dialed in?

            So, Tom, a.k.a. BB Pellitier, could a fifth article be encompassing adjustable scope rings – if any are, in face made today?

  4. A most interesting topic. I really enjoyed the blurb about the reticles. I remember the steel wire reticles when I was rebuilding Mossberg scopes. I do not remember having encountered spider web reticles, but I have not peered through any really old scopes.

    I am with Siraniko on wanting to know more about etched glass reticles.

    Low scope mounting is the one major drawback when dealing with AirForce airguns. It is difficult to get a good eye alignment with the airguns that use the “large” diameter bottles unless you have an aftermarket canted or offset bottle mount. Of course, you can use high mounts as long as you are aware of the cant issue. You would think that as many bottles as AirForce uses that a manufacturer would use threading to accommodate AirForce. I guess their attitude is that AirForce should change their valve threading, which they have on some models.

      • What a shame Tom Gaylord (B.B. Pelletier). I would have liked to hear/read your take on how best to achieve long distance accuracy with precise handguns.

        For me it would be my precharged pneumatic revolver.
        I think of the Weihrauch 44 as ‘The Beauty and The Beast’, ie beastly to look at but beautiful to shoot. 🙂

        • >>> I think of the Weihrauch 44 as ‘The Beauty and The Beast’, ie beastly to look at but beautiful to shoot. <<<

          hihihi,

          That sums it up well!

          The HW44 looks a little odd but feels good in the hand and is very nice to shoot. The trigger is great and the accuracy excellent! Love that the cocking handle is conveniently located on the left side – saves shifting the pistol hand to hand when reloading.

          Well designed, well made… typical Weihrauch 🙂

          My .22 HW44 is my favorite plinking pistol!

          Hank

          • Vana2, you lucky lad! 🙂
            First, that yours is in the larger calibre (mine’s in .177″), and second, that the Beast seems to fit your hand, you see, it’s rather tight for me, ie too much of a squeeze to squash my hand right into the grip.

            Wonder if and how the grip can be adjusted?
            Anyone?

      • This HW44 “Beauty” reminds me of the 4 Thompson Contenders, in various rifle calibers, my wife’s father left us. All were scoped as he was an avid Metallic Silhouette competitor in hunter pistol class. A couple long eye relief pistol scopes were included but most were rifle scopes. The two-handed “taco grip” was often utilized.

          • hihihi
            From gunandgame.com forum:“The taco grip is a usually over hand-grip often seen with longer pistols like the T/C Contender.

            Your shooting hand holds the pistol grip as usual and your support hand extends out (thumb towards you, pinky finger out furthest and you sort of overhand grip your scope/scope base to increase front end stabilization of the longer barreled pistol.

            This is often used by hunters in a non supported stance like standing or crouching but it is used heavily by pistol silhouette competition shooters to reduce first shot recoil and front end muzzle sway.”

            Here’s a link with some photos-

            https://www.airgunnation.com/threads/how-to-hold-for-field-pistol.487762/

            http://mrcompletely.blogspot.com/2006/06/taco-grip.html
            As you can see in these pics, there are are variations that increase stability with long barreled pistols typically using rifle scopes.

            The two long eye-relief scopes are pretty basic models from the 70’s-80’s. One is a Thompson Center variable power 2.5-7×28 mounted to a Contender 32/20 barrel. The other is a very basic Tasco 4×28. Both have 12-14 inch eye relief. Could also be used in the forward barrel mounted scout rifle/scope configuration on a multi -pump air rifle, making for easier pumping action by removing receiver mounted scope interference.

          • hihihi,

            No room to reply above to: “Wonder if and how the grip can be adjusted?
            Anyone?”
            IF it is really causing you to not like shooting the pistol or worse still you feel it is hurting your accuracy get out the RASP and remove the offending synthetic material a little bit at a time. The parts diagram seems to show that grip module includes the trigger guard and more. If you feel nervous about that process order a replacement part before you start rasping away material. That way you can instal the new grip and suffer or sell the pistol.

            shootski

            PS: you could also try the Creedmoor position to see if the grip fits better in that position. Just make sure the ground isn’t wet or you have a good shooting mat to lie down on!

          • Thank you Remarq. I imagine a rather steady hold to make use of those scopes’ magnification. Thanks for the picture.
            Now I have learnt the (non food related) taco grip. 🙂

          • shootski, that thought did occur to me as well.

            I once did that to a wooden pistol grip. The attached picture shows what’s left of it! 🙂

            Thankfully the HW44 isn’t as bad as my FWB103 was! 🙂

  5. BB

    I seem to recall your making this point in some earlier report If I have it right, high magnification scopes that require exact eye location do help overcome parallax error. This seems to be the case with some scopes I have mounted. Slight eye movements in any direction darken the image so much it becomes automatic to adjust your eye location to the correct place. I like these scopes for informal target shooting where there are no time constraints to worry about.

    Me too on etched glass.

    Deck

  6. BB,

    Wish that the scope ring manufacturers would include the actual ring height in the description of their products.

    Considering that many purchases are made on-line, estimating the ring height is all but impossible. The terms low, medium, high are useless when trying to mount a scope high enough to avoid interference between parts of the rifle and parts of the scope but not too high for a proper cheek weld.

    Just a pet peeve.

    Hank

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