This report covers:
- What have we learned?
- And the rings?
- The objective side of the scope
- The deal
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We learned that scope reticles were originally made from spider silk and then in the 1930s steel wire was used in scopes used on rifles that recoiled softly, because steel wire couldn’t take the recoil of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.
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.
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.
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.
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.
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.