5 Overlooked Keys to Know Before Buying a Riflescope

Not all that long ago, when a hunter was considering a new riflescope, magnification was the only real concern. However, the riflescope has since evolved. It's no longer just a magnifying tube with an "X" in the center. Modern scopes are marvelous optical sighting devices. Now things like objective lens diameter, exposed target turrets, click adjustment value, zero stops, illuminated reticles and trajectory- and wind-compensating reticles are all popular considerations when selecting a riflescope. Some modern options even have an integrated rangefinder or an interface with a separate rangefinder, and then provide you with a shooting solution.

All these things matter when choosing a riflescope. However, in trying to pick the newest, best, brightest and smartest scope, some other key features often get overlooked. Below are five things you should not ignore when evaluating riflescopes. Depending on your rifle and what and how you hunt, some characteristics may be more or less important than others. Just ensure you don't discount any of them entirely.

MOUNTING SPACE

I believe this is the most overlooked riflescope feature. By mounting space, I mean the available space on a scope's tube where rings can be placed. It’s the unobstructed space behind and in front of the saddle at the riflescope’s center where the adjustment turrets are located. This space determines how far you can move the scope in the rings; it's how you adjust eye relief, and eye relief is a key part of user interface with riflescopes.

I recently tested a bunch of new riflescopes, and the available mounting space ranged from as little as 5 inches to as much as 6 3/4 inches. For bolt-action rifles chambered for cartridges like the .308 Winchester, you need at least 4 1/2 inches of mounting space, and for long-action cartridges like the .30-06, you need about 5 inches. Those measurements are just to mount the riflescope; to adjust for eye relief, you'll need more mounting space. If your rifle has a rail-type scope base, mounting space is usually not an issue, but for non-railed rifles, it is an important consideration.

OCULAR HOUSING SIZE

The ocular housing, or eyepiece, is the rear portion of the riflescope that contains the ocular lens. It's the end of the scope you look through. Large ocular lenses are nice because, to some extent, they are like a big-screen television. However, with bolt-action rifles, the bolt handle must clear the ocular housing when the bolt is cycled, and larger ocular housings require higher rings to accommodate this. Higher rings can make it difficult to look through the riflescope while maintaining a good cheek weld on the stock.

At only 1.56 inches, Leupold's VX-3HD riflescopes have about the smallest ocular housings available. In comparison, the eyepiece diameter of many modern riflescopes is about 1 3/4 inches.

But eyepiece diameter is not the only concern. Many riflescopes have even larger magnification adjustment rings, and the bolt must clear that as well. Some, with a raised power setting bump or indicator, can exceed two inches. This means the riflescope must be mounted even higher for bolt clearance. Also, magnification throw levers are becoming very popular, and quite often they, too, interfere with bolt operation, especially when set at maximum magnification.

RETICLE INSTRUCTIONS

A riflescope feature that has really evolved is the reticle. Many of today's reticle styles offer additional aiming points to compensate for trajectory and wind. To use these reticles properly, you must know what the spaces between these aiming points subtend to. For MOA- or mil-based reticles, this will be in MOA or mil increments. For some ballistic-style reticles, these subtensions are proprietary to the reticle design.

Most riflescope manufactures detail their reticles online, giving all the necessary information. But some, like Vortex and Meopta, provide detailed reticle instructions in the box with the riflescope. However, I've also seen riflescopes where the reticle information must be classified because you simply cannot find the data anywhere. If you must, you can work this out on a target with grids at 100 yards, but data from the manufacturer is most appreciated. Look for information on the reticle before you spend your money.

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WEIGHT

Because of long-range shooting’s popularity, large and heavy riflescopes are trendy right now. For that shooting discipline, weight isn’t critical. However, for hunters it can be.

The new Zeiss LRP S5 3-18x50 is a spectacular long-range riflescope, but it weighs two pounds. Add it to Nosler's excellent Model 21 rifle, and you're now carrying around nine pounds. For those who hunt out of shoot houses, that’s not a big deal. If you’re climbing mountains or walking prairies, it matters.

By comparison, Leupold's VX-3HD 4.5-14x40 riflescope weighs less than a pound. And, with its Custom Dial System (CDS) that can be tuned to your ammunition, out to 400 yards or so, it's just as effective as the larger and heavier Zeiss. The point is, don’t over-scope your rifle; a heavier riflescope doesn’t make you shoot any better. Find the features you need for the hunting you like to do, and don’t overlook riflescope weight in the process.

PARALLAX

Parallax is a very important but often misunderstood aspect of riflescopes. You can check for excessive parallax by resting your rifle, so it is fully supported, and then looking through the riflescope and moving your head from side to side. If the reticle moves in relation to the target, parallax is present at that distance.

Some riflescopes—especially long-range riflescopes—have adjustable parallax, and it's a must for a big-game riflescope intended for use at extreme ranges. Riflescopes without an adjustable parallax have their parallax set at a specific range. In most cases it's between 100 and 150 yards. This means that out to around 400 yards or so there won't be enough parallax to drastically impact your shot on a big-game animal.

Parallax is very important for rimfire riflescopes, especially for small-game hunting. A riflescope with the parallax set at 150 yards might show as much as 1 1/2 inches of parallax at 50 yards. A shot that's 1 1/2 inches off on a big-game animal usually isn’t a big deal. However, if you're trying to head-shoot a squirrel, your own head will need to be perfectly positioned along the center line of the riflescope to eliminate the parallax.

Thus, most rimfire scopes have the parallax set at 50 or 60 yards. However, if that's the case, you can expect excessive parallax at 100 yards and beyond. As with a long-range big-game rifle, a riflescope used on a rimfire rifle for small-game hunting can benefit from an adjustable objective.

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