When upgrading or buying a new scope for a rifle, there are a great variety of brands, types and models to choose from. I'll try to explain the scopes, their features, and their uses.
First, define the gun and the use it will be put to. Will it be used in wide open spaces, early morning/late evening or midday, in heavy but open Western brush, under a thick canopy of leaves, or on the open plains? Is it a short, handy carbine, or a big, flat-shooting bolt action, a rifled shotgun or big dangerous-game magnum?
Short, handy carbines, like Marlin and Winchester Model 94 levers, the Ruger Mini-30, etc. should have a short, handy scope. Large, high-power variable scopes are the worst choice. They have a short eye-relief: you have to hold your eye quite close to it, and at a precise distance, too, detracting from the quick-handling nature of the gun. They are heavy. A large objective (front lens) lessens the handiness in heavy brush, and must be shielded from knocks at all times. High power also means a narrow field-of-view, which means you can see something close by, put your eye to the scope, and then spend a couple of minutes trying to find it.
Good choices for carbines are usually fixed low-power scopes. They have the widest field of view, for quick target acquisition. The fixed power means less moving parts in the mechanism, making for a sturdier instrument. Being low power, they do not need large front lenses to gather light well in dark wooded areas. Four power scopes are the most popular in this class.
What holds for carbines is also true for slug-firing shotguns. With long receivers and even longer recoil, shotguns often call for Intermediate Eye Relief scopes, to prevent eye injury from the recoil. Scopes in this class typically have a magnification power in the 1.5x to 3x range.
Flat shooting high-power rifles are increasingly popular nowadays, even in areas where short-range brush hunting used to dictate the use of handy, lever action carbines. I suppose that this is the "My equipment is bigger than your" syndrome. I don't let that stop me from carrying my lever action Marlin. Anyway, one of the best hunters I knew of (R.I.P.), used a Burris brand fixed four-power scope on his 7mm Remington Magnum. Mostly these guns make for bloodshot meat and are overly destructive at distances less than 100 yards. For hunting across clearcuts, farm fields, and open countryside, a higher power scope would be in order. The popular 3-9x variable power scopes with 32mm objectives are good choices. If hunting will be done around sunup or sunset, a larger 40mm or 44mm objective will be in order. For hunters who must take long shots in dark, misty woods, a quality 50mm objective scope might be desirable, if they are willing to tolerate the size and weight. For most hunters, 32mm gathers enough light for daytime hunting and preserves reasonable size and handling.
Varmit hunters and target shooters have certain luxuries and certain liabilities, as well. Heavy rifles, scopes with large targets knobs (that would be easy targets for field breakage), comfy seats and rifle rests are all normal. This makes large, high power scopes more practical. The high power is also needed for precision shooting- the vital area on a big game animal is larger then an entire praerie dog, for example. Since targets are stationary and/or distant, field of view is less critical. Large objective lenses are needed to compensate for the amount of light lost to the high magnification. Sensitive mechanisms can be babied on heavy, easy-recoiling guns of moderate caliber. Short, precise eye relief can be tolerated on the bench stabilized gun. Fixed power scopes of 15 to 30 power have been popular, but recently variable power scopes have been in vogue.
Finally, a cheap scope on a quality gun is like plastic earings worn with an evening gown. A rule of the thumb is that you should be spending about as much for the scope as you did for the gun. This may be a hard pill to swallow for some, but a $400 Leupold is a good compliment to a $400 Remington 700 or a $500 Winchester Model 70. A $40 third-world manufacture X-Mart scope is going to let you down when you most need it, after a long hard stalk on an expensive hunting trip. Does that save you any money?
Good brands typically contain US or Japan made optics. Redfield uses Japanese optics but assembles entirely in the US. Weaver's scopes are made entirely in Japan by Light Optical Works. Before the bankruptcies and Blount, Inc. buyout they were US made. Karl Zeiss now uses Japanese optics. Several brands thought to be Japanese products, or formerly Japanese, now use Korean optics, and are of very miserable quality.
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Simmons and Bushnell make some of their scopes in Korea. This was the case before Simmons was purchased by Bosch&Lomb/Bushnell. I've heard that Bushnell's better scopes (the Trophy line, I think) are made by Light Optical Works in Japan. Apparently, B&L (no surprise), Weaver, and Nikon scopes are made at L.O.W., also. A vendor can choose their price point and quality level and L.O.W. will accommodate. So, don't buy a Bushnell Trophy and expect it to be as good as a Nikon, even if they are made in the same place. Since being bought out by Bausch & Lomb, Bushnell has been relegated to poor (Sportview, Sharpshooter) and moderate quality (Trophy) scopes, while the good stuff (Elite 3000/4000) carries the B&L brand name. I have an old Bushnell Sport King II in 3-9x38mm, of indeterminate origin. It has a huge eyepiece, good eye relief, exit pupil width, but some parallax. A recent Korean-made Sportview and a late 80's Sharpshooter have parallax problems that must be seen to be believed, even after a trip to the factory. A look at the web page specs of the neck-craning, eye-bopping 3 inch eye reliefs and the view-occluding 3.6mm exit pupil on the 3-9x32mm makes one wonder why they bother.
Nikon doesn't mention their scopes on their web page, which makes the L.O.W. out-sourcing information more credible. Or, maybe they don't want to offend the AR contingent of their customers, and are not worried about reaching conservationists who hunt.
Pentax keeps with the Japanese tradition of hiding their sporting involvement from the Politically Correct world by not listing their Lightseeker Scopes on their Web page along with their cameras and binoculars. I would expect the optics of these scopes to be excellent, but I doubt if I'll buy one, until they are unafraid to admit on the Internet that they make products for hunters. Their Made-in-USA scopes have the same design features as Burris, like self-lubricating brass inner tubes. Their new Lightseeker II features Burris's Posi-Lock reticle locking system (Pentax calls it Perm-Align). Pentax touts its well-known Super Multi Coating system on all lenses.
Recently introduced Norinco scopes are made in the People's Republic of China, of course, and are poised to establish a new low in both price point and quality. As brand-named manufacturers move labour and technology there, in a few years we might seeing quality optics out of China, but not yet.
Tasco is trying to enter the middle-end market with their Tactical and World Class model scopes. Every new Tasco I've ever adjusted had an adjustment increment that didn't even vaguely resemble it's actual travel, either in a collimator or on the paper. Several older models had floating reticles, (boing, boing). Their 25x Mini Spotting Scope has an incredibly short eye relief, about 1 or 1.5 mm. I can't use it because it irritates my eyelashes, I keep bouncing my eyeball off of the lens, and the exit pupil is so small I can't hold my eye still enough. If they really want to be taken seriously, they should drop the Lumina and Pronghorn line of scopes and pretend they never existed. If their World Class scopes use the same internal mechanisms, forget it. I refuse to buy even middle-end Tasco's and Bushnell's, as long as they market their miserable low-end scopes.
Burris uses US-made multi-coated optics on the high-end (actually middle) Signature brand, and also their Fullfield brand scopes. Their Mini scopes are listed as US made but not 100% US parts, so I suspect they use imported optics. They have put a lot of work into Reticle position integrity, including a "Posi-Lock" system that locks those crosshairs in place after sighting-in. Burris and Pentax scopes share a lot of technology.
Leupold makes the Vari-X II line, which typically has 1/2 minute adjustments and a very good Magnesium Fluoride (MgF2) single-coated lens system. Vari-X III's run a hundred or more dollars than the II's, and have multi-coated lenses and 1/4" click adjustments. Leupold has a fanatical following and is well known for its excellent customer support.
Redfield uses Japanese optics in US designed and constructed scopes. Like several other middle-end brands, they use one-piece scope bodies, that have no threaded joints at the middle to leak. My Ultimate Illuminator came with an impressive list of tests that were performed on it before sale, and I have found there Customer Support to be very helpful. Redfield often suffers in comparison to Leupold because the bulk of the Redfield line lies in their economy Five Star brand, while Leupold offers a full line of higher-end scopes. To be fair, one should compare scopes of similar price and features. In comparing feature for feature, I would guess that the Widefield line would be comparable to the Vari-X II, and the Illuminator and Ultimate Illuminator lines with the Vari-X III. This comparison is still a little stilted, as Redfield does not offer the breadth and width of models in these lines, nor does Leupold offer a 56mm objective or a 30mm body.
Redfield, Weaver, Leupold, and Burris all have good reputations for middle-end scopes. They have each had their clunkers and an occasional QA mishap, but all have many staunch defenders who have used many of their scopes. They also offer excellent factory support and repair services. Zeiss, Steiner, and Sowarski are high-end scopes that cost from $600 to $1500 for typical models.
My only experience with Simmons is a shotgun scope that shifted center of impact vertically 10 inches at 100 yards (5 inches at 50, etc.). I sent it back to the factory and they claimed the problem was a parallax problem. I checked it from the viewer's perspective for that, and it didn't shift the crosshairs significantly when changing eye position. It already cost me a 60 yard profile spine shot at a deer, I'm not going to trust it again. Maryland's hunting seasons are too short to risk losing any shots. I thought it was a better brand then Tasco when I bought it, because it cost me $80 instead of $40. Given my negative experience and it's Korean manufacture, I'm not inclined to give it any more chances with hunting.
(Well, I just re-tested the Simmons, and it still has the same problem. Mark one against their factory service, as well as the original strike against QA/design.)
I suppose it's possible to by a cheap scope and be happy with it. The hunters that I help sight-in don't have to experience my frustration when I try to get their scope reticle to move the required distance to make zero. As long as the scope is not banged and it stays relatively unused, the reticle adjustment may stay overly stiff and not float. Many shoot only during the hunting season, and can leave their scope zeroed for use with one load, because that's the only load they will use all year. If shots are kept to a moderate distance and the objective was accidently adjusted to a reasonable parallax setting, shots can be kept inside the kill zone on large game.
While every hunter I know takes hunting and shooting very seriously, many only shoot their deer rifle once a year. I suppose the low-ball scope companies are betting that most hunters won't have a noticable problem during a limited amount of use. As for me, I save my money for reliable, sturdy equipment.
Some definitions.
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Repeatability Every experienced shooter knows that different weight bullets, and different brand loads, shoot to different centers of impact, even in expensive guns. With a quality scope, scope adjustments are repeatable. This means that if 20 clicks left will zero when changing loads once, it will always, and 20 clicks to the right will always take you exactly back again. On a cheap scope, each click is variable in adjustment, often a shot or two must be fired before it settles in, and adjusting it back doesn't bring it back to the same place.
Glare Glare results from light entering the scope from angles outside the viewed area, and being reflected inside the scope, joining the light intended to be viewed. Internal baffles and scope tube darkening treatments stop this light and reduce glare. Cheap scopes lack baffles, and have brushed-aluminum, anodized or painted internal surfaces, which are fairly reflective.
View Quality scopes precisely ground optics and expensive Multiple Coatings. They have less color bleed, transmit more light, and have less edge distortion. All this can mean the ability to pick out antlers among the branches, and brown fur amoung the Autumn leaves. They also have a longer and more forgiving eye relief and a bigger exit pupil, making them more comfortable and easier to acquire the proper sight picture. They often have a wider field of view than comparably powered cheap scopes, for faster target acquisition.
Reliability After bore-sighting a couple dozen scopes, I noticed that the dime-store scope adjustments are very stiff when new. A few shots must be fired to force large adjustments to take. On the other hand, older cheap scopes move very freely, whether they are being adjusted or not. Either way, adjustments to the vertical affect the horizontal, and vice-versa. I've seen some cheap scopes that actually have portions of the adjustment range that move backwards. Cheap scopes have more joints, and are more likely to lose their seal integrity and fog-up.
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Pick up an issue of Popular Photography, and take a look at the camera lens tests they publish in every issue. (Some examples here.)
Everything thing they test is applicable to scopes. So, where are the tests for rifle scopes? Who dares to publish the truth? No one.
I challenge reviewers to be true journalists and test the following factors of any scope they review:
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