Home Forums Hunting & Shooting Ask The Gunwriters power change & accuracy

For more than a quarter of a century, I've been advising against putting too much reliance on the accuracy of variable-power scopes. I've cited personal experience from checking well over a hundred variables from all over the world. Might as well have been spittin' into a hurricane.
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<br>Now a friend has given me a January 1982 Zeiss brochure that prominently displays this very factual gem of wisdom, under the heading "Power Change Affect [should be "Effect"] on Accuracy of Scope:"
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<br>"One important facet of scope quality usually glossed over or ignored completely by other manufacturers is the variable scope's propensity to shift point-of-impact (POI) at different power settings. Again, with some scopes this shift is negligible; with others it's not. Some, for example, showed a 1.8 inch deviation on a 100-yard target between where the crosshairs were at 3x and 9x. That's 6.3 inches of error at 350 yards. With all the other things going against you -- like wind, mirage, range estimation, lack of a steady rest and maybe a little buck fever thrown in for good measure -- you don't need a scope with a built-in miss!
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<br>"Our C-Series scopes are guaranteed to have a shift in POI throughout the power range of less than .7" at 100 yards. This is equivalent to the diameter of a dime."
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<br>NO scope available is more dependable than the understandably pricy Zeisses. If the best of 'em all can't eliminate POI shift in a variable, then what is it reasonable -- or even sane -- to expect from a relative cheapie variable? (FWIW, a friend of mine licensed his patented design for an electonic rangefinder scope to a prominent American "manufacturer" who has his scopes made in Japan. That scope never made it to the market, because the factory couldn't make it for less than ten bucks a unit.)
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<br>... just one of the reasons I don't like variables for serious shooting.

We are definitely in agreement on this one. Even without your expertise I figured out long ago that variable meant just that, "variable" not consistant. I chose to only use fixed power scopes in the 4x and 6x range on hi-power and stick to 2.5x on rimfire, has always worked for me. I am a firm believer in "If it ain't broke, don't fix it."
<br>Oh yeah, I don't try for those 500 plus yard shots either, try to keep it under 250, beyond that I'll pass anyway.

FINALLY!,
<br>Thanks Ken.
<br>We knew this years ago but it seems to have gotten lost in the quest for "bigger and better".

I am glad to see this post. I am getting increasingly irritated with the variable scopes and the increased magnification at the high end. Honestly, what big game hunter needs a 4x14 scope on his elk rifle? How about a nice 4X or 6X and leave it at that. If you need binoculars, carry a set rather than using your scope.

Ken,
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<br>This post of yours has been spining in my mind since yesterday. I agree with you and the quote. The sad point is that all my hunting arms have variables on them. I sight them in at a set power and leave them there.
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<br>The reason I have these variables is simple. I can not find a good fixed with the optics of the VariX-III level except the leo 6x42, and I DO NOT hunt at 6x. I wish I could find a 4x and 2 or 2.5x with true multi coated optics other then the very expensive euro lines. I would love a straight 4x32 with the good lenes. Scope small enough that I could mount it low, and a 2.5x with straight tube for the lever 44.
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<br>If you or anyone else know where and how to get a good fixed with the good lenes, I for one am very interested.

Pick. My understanding is that lense coatings allow more light to pass through the scope undistortred.
<br> However, in comparing the Leopold 3.5-10X VariXIII Longe Range scopes, to Leopold's fixed power 10X Mk.4's, I noticed the fixed power 10X scopes have a brighter image. Probably because of the extra lense in the variable.
<br> I suspect you wouldn't notice much difference in image quality, or brightness, between the a fully coated 4X, and one coated like the Leopold 4X. In fact, I've used a 1.75-6X VariXIII Leopold along side a 4X 28 mm Leopold and couldn't see a difference. What are your observations ?
<br> I've also been reluctant to use a 6X scope on a hunting rifle. That is until somebody pointed out the math. A 4X Leo has a FOV of 24 feet at 100 yds. That means only 6 ft at 25 yds. A 6X42 has a FOV of 17 ft. @ 100 yds. And, at 25 yds. a FOV of about 4 feet. But that still gives you an error of 2 feet, at that distance, while the 4X gives you only another foot. The 6X42, BTW, has a very forgiving eye relief, unlike many variables. Nice, if your in a hurry. E

I have a 3-9x40 Wide Angel scope. I would tell you the manufacturer, but it isn't on the scope. I normally have it zeroed 2 inches high at 100 yards for deer season, my 7x57 Mauser. I took about a 200 yard shot at a deer, with the scope on 3x. I normally sight in with 9x, and use 9x a lot while hunting. I aimed for the head, and it the neck, about 4-5 inches below where I aimed. I would guess this is due to scope variation. I should see that sometime. It would be a neat experiment. First, I have to figure out who made the scope, lol.

I thought it was common knowledge that variable scopes can shift poi at different power settings. Dosen't everyone check for this at the range? Do you also check the repeatability of your scopes cilck adjustments? Knowing what your scope does is one of those detail things that make the difference between killing prairie dogs and just shooting at them.
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<br>Anything that moves has slack in it. The better the quality ( tighter tolerances) the smaller the slack. Even the threads on a fine screw ( the adjustment screw on a good peep sight for example ) have an amount of slack. When you make an adjustment go past your mark and then tighten back to it. Take out the slack, consistant technique gets consistant results.

PDS, it SHOULD be common knowledge that variables shift POI with power changes -- but it isn't. The hype from manufacturers and magazines, combined with the predominance of variables on the shelves and in the catalogs, has drowned-out all common sense about optics selection as far as most shooters and hunters are concerned. You'd think Moses brought variables down off the mountain as prescribed by The Almighty, from the way they're generally regarded.
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<br>You've mentioned slack. One of my tiresome points for lo! these many years is that anything that HAS to move when you want it to move CAN and WILL move when you don't want it to move. This is why variables also sometimes shift POI at a given, set, unchanged x setting. Their guts move around. Have to.
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<br>A large root of the problem is the mistaken notion that every scope must magnify your target. Part of this foolish notion is the assumption that making it LOOK bigger makes it easier to hit. Nope. It's still the same size, still as far away, with the same size of scoring or killing zone. Magnification is necessary and useful only when the APPARENT size of the target is small -- because the target is indeed small, or it's 'way off out yonder, or both little and distant.
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<br>The finest big-game scope I've ever used is a 1x Weaver K-1. A Weaver K-1.5 is almost as good. At the ranges and under the conditions where I've shot elk, caribou, and moose, I don't have to have those critters magnified to see 'em well enough to pick a spot and put a bullet there.
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<br>Prairie dogs at 500 yards and gophers at 300 present an altogether different set of considerations -- but I don't remember many other field situations where I needed either a very high magnification or a menu of several magnifications.

E,
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<br>The multcoated optics do more then just let more light in. I have noticed that they really do reduce the 'flare' factor. In the more Northern Latitudes the sun hangs low to the horizion. A lot of scopes will flare out if the sun is close to the axis you are looking out. The VariX-III's seem to have the best coatings for that situation of all the scopes I have. I have Burris Siginture 2-8x, Bushnell 4200 1.5-6x, and a VariX-III 1.75x6. I hunt with all of them at thier lowest settings. I have more rifles and scopes, but all the center fires wear either Burris Sigintures or VariX-III's. I have tried the 2.5x and 4x models from both Burris and Leopold but when it comes to the sun flare out issue they are much worse then the multi coated optics of thier top line variables.
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<br>As Dr. Howell rightly points out about POI issue, there is also the issue of sight picture. I have hunted with people that are contstantly changing the power setting to 'macth' the situation. When a shot presents itself they get all confused looking through the scope, mostly misjudging distance and size.
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<br>I personally like 2x and 4x power for the following simple reasoning on my part.
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<br>2x makes the view seem 1/2 the distance and it is easy for me to keep a mental note that distance appears 1/2 and size twice what is real.
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<br>4x does what the 2x but again. Inother words is doubles the size and then doubles the size again. Same for distance, cuts it in 1/2 then again by 1/2.
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<br>This allows me to hunt using the KISS system. I practice at these settings and I do not filddle with the power ring. And I give H*** to anyone in hunting camp the touches the power ring, even it they set it back. I am grumbled at in the cabin, since if the power ring has be touched I immeditly take said rifle and scope behind the cabin and recheck zero. In my book there is no excuse for not knowing where you aim is where the bullet will land.

I gotta listen to guys razz me on the 6x42mm Leupold. It's my favorite all arounder,for killing critters.
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<br>I have and use variables. I had two particular Burris that were horrible at shifting POI,through the zoom rage. Leupold has yet to disappoint me.
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<br>Was reading a couple nights ago,about a new etched mil-dot reticle for Leupolds,that will debut from Premiere. That will be a plunge I plan on making. A 4.5-14xLR,with that reticle,would be right up my alley on a couple different rifles I have in mind.
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<br>Thoughts regarding a POI shift,with the etched reticles?..................

Big Stick,
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<br>I will not razz you on the 6x42, but I often have running, and I do mean running shots at less the 30 yrds sometimes as close at 5 and I am only going to get ONE good shoot. In those situations the 4x is real hard to get on and pick the shot. Here is where I find the 2x the best. For that my two best scopes currently are the 1.75-6x VariX-III and the 2-8 Burris Signiture. The VariX-III is in truth a 1.9 to 5.7x and I leave at 1.9x (close enough to 2x) and the Burris I leave on 2x. At these power settings I can pickup a running deer and have enough lead in the view to spot the breaks in cover so I can place the deer bullet and opening at the right time and place. Did I mention that I hunt the brush a lot. Most places that I hunt after the first 10 minutes of season the deer that are still alive go to cover and stay there. If you want your deer you dig them out. No matter how good the 6x42 is I just can not see myself using in this type of hunting. For all the other shots it would be great.

"Thoughts regarding a POI shift,with the etched reticles?"
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<br>The type of reticle isn't the problem. The problem lies in all those necessarily unanchored internal lenses and the mechanical parts that move those lenses to and fro to change the magnification of the scope. The reticle is usually fixed in place, I believe. Exacerbating the problem are the two requirements that (a) there are several unanchored parts and (b) all such parts have to be both small and light. They can't be fewer, and they can't be bigger or heavier.

Mmmmm,it seemed to me an etched reticle,would be another static part and eliminates one piece of the mechanism. Wouldn't that help the reliability of the overall system? I don't know if work is done to the zoom tube,to help it's tracking? But the Leupold M3 3.5-10x is LEGENDARY in durability and accuracy.
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<br>Next time I go to the range,I'll bring a truckolad of rifles and try to detrmine POI shift,with some variables. As mentioned,I've never noticed it,with Leupold.
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<br>In regards to the 6x42 Leupold. My son shoots one on his 223,for Deer. I've put him on two Bucks,that were closer than 15yds. He connected easily. I like that glass on a 375. The eye-relief,field of view and durability,appeal to me. I don't tote a 375,unless I'm in the puckerbrush. I very much like that glass,in that aplication.
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<br>I just can't "do" a 4x or lesser glass. I've got them,but disfavor them in comparison..............
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Color me dense if you like, but I simply can't understand why anybody needs magnification to see where to shoot even a gopher or a prairie dog that's close enough for the unaided eye to distinguish its eyes, ears, nose, or hair. I can see a deer pretty well at distances far beyond what I can see in close brush. And my eyesight isn't anything to brag about.

Same reason I have 22-250's in the closet,instead of all 22lr's..............

Everyone else's experience may vary. I've killed nice bucks, at close range ( minus 50 yds.) that I couldn't see, but a patch of hide, or two, with the naked eye. I needed the scope to verify that they were what I wanted, and to find a hole to shoot through.
<br> I've shot critters in light so bad I couldn't see them clearly with the naked eye.
<br> My vision is fine. I can read two lines below 20-20 on an eye chart. My night vision is 1 st class as well. I can still use a 7 mm exit pupil optical equipment, for instance.
<br> In other words, I don't need a scope to see them when they are in the open, and in good light. But, often, they don't co-operate. Especially the nice ones.
<br> I've also noticed that the nice ones give you very little, if any, sort of running shot. They disappear right now. If you don't see them first, you usually loose.
<br> That's why I insist on binoculars for hunting-even in heavy cover. And, I insist on the best, the most, clarity I can get. E

Ken,
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<br>I will see if I can satiify your 'dense' (to quote you ) part. I fine the following advantages in a good scope.
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<br>1. I see the whole target, not just the upper 1/2 as when using open sights, This can and is done well with 1x glass, so this is not a maginification issue as much as a sight picture issue.
<br>2. I like 2x or 4x when still or stand hunting so when I go to take the shot I can verify that the path is clear. Here the magification does help make out small twigs and such you would not see with the eye alone. Also on good optics the contarst and colors come through better then with just eyes alone. This is due to a good optic killing almost all the difussed light and the coatings 'purifying' the color and tints for lack of a better word.
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<br>My personal limit is 200 yrds even if the rifle is capable of more, which most are. For me there is just to much that I can mess up past 200. Now that I stated why I like and use scopes, let me state what I do not like about any of then.
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<br>1. They are all to big and truly do not look like they really belong on a rifle. This is my personal taste and thoughts on this.
<br>2. and this get me almost once every season. No matter how good the scope, it is nearly impossible to keep the lenses clear in heavy rain or snow. And if the lenses are not clear you can not shoot good... period. When the weather is really nasty and I am out hunting this where the 44mag with fire sights is surpreme. In this type weather you will not see or shoot beyond 50 anyway.

Please note that I do not criticize or question using a scope on a hunting rifle.
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<br>What I question is the obsession for MAGNIFICATION (especially the old "the more the better" idea) when both the target and the intended impact point are already clearly visible to the unaided eye. I've used good and bad scopes from 1x to 24x since the mid-'Forties and have 'em on more than a dozen rifles, with extra scopes all around the place. I'm not against using scopes.
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<br>But the idea that shooting deer within a hundred yards should require a great deal of MAGNIFICATION seems downright foolish to me. My all-time favorite BIG-GAME scope -- the most under-rated, under-appreciated hunting scope ever made -- is the 1x Weaver K-1. Weaver gave it the kiss of death at birth by hyping it as a shotgun scope. Its clarity and field of view are amazing. I wish I had one for every deer and elk rifle in the house. Fortunately, I got the last one there was at the Weaver plant, left over by accident years after the K-1 was discontinued. Unfortunately, it was the LAST one -- and only ONE.

I've got several K-2's, and would trade two of them,for one Leupold M8 4x or 6x(in any condition). Or a 3-9x VX II.
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<br>Hopefully nostalgia will get the best of someone's judgement and I'll have another Leupie with turrets..............