What makes an airgun scope?
by B.B. Pelletier
Riflescopes have changed significantly over the past 20 years, and airguns have lead the way. Things such as parallax adjustment, sidewheel parallax adjustment, and adjustable scope mounts have all come out of the demand for better scope solutions by airgunners. And, because of all these changes, what airgunners "know" about airgun scopes has also changed - perhaps too fast for most people to keep up.
Airguns no longer break scopes!
In the 1970s, scoping an airgun was problematic, because all the scopes then made were made for firearms. Scope breakage reared its ugly head about the time the great horsepower race began. Airgunners wanted guns that went at least 800 f.p.s. - the minimum speed for magnum status. To build guns that could do it, airgunsmiths created guns with more forward recoil and vibration than had been seen up to that time. Scopes started breaking. A .30-06 recoils more than nearly all airguns, but it kicks the rear - not to the front. So, scopes were braced for rearward recoil. A .375 H&H Magnum kicks pretty hard, but it doesn't vibrate. A Diana 45 with a leather piston seal and sloppy internal tolerances can give you a headache from the high-speed vibration. That's why the early scopes broke.
Scope makers didn't advertise the fact, but in the 1980s and early '90s they quietly cleaned up their act. It's difficult to find a scope that's not properly braced for an airgun today. A few cheapos from China are all that remain of this once-widespread malady. Scopes don't break - as a rule. That said, airguns are still hard on scopes, and individual scopes will still break. I hope you understand the difference.
In scope manufacturing companies where there are real optical engineers, the subject of parallax adjustment is understood very well. Leupold was at the front of the pack in the early 1990s with Premier Reticle, an independent customizing house that specializes in Leupold modifications, leading the way. I can remember being shocked to learn that Premier Reticle could bring the adjustable parallax of a 6.5-20x scope down to as close as 10 yards. Today, Leupold offers the scope that way off the shelf, but so does nearly everyone else.
However, you should be aware that some companies that don't actually produce the scopes they sell. With today's world market, it's possible for anyone to become a manufacturer by aligning with the right Chinese company and getting them to put your name on some scopes. When two guys in a garage decide to make riflescopes and they haven't got a clue what parallax adjustment really is, you'll see goofball minimum distances like 20 or 25 yards. All that does is signal a company that hasn't got anyone on their staff who understands the market. Airgunners don't want 20-yard minimums - field target drives a 10-yard minimum (and Leapers drops it down to 3, just because they can). Rimfire shooters don't need 20 yard minimums, and centerfire shooters barely know what parallax adjustment is. A company with scopes set to a minimum parallax distance of 20 yards is a company that's out of touch with potential buyers of their products. China will make anything you want.
I'm saying that to be a proper airgun scope, the parallax adjustment must go down to not more than 10 yards minimum.
WHERE is the parallax adjustment located?
AO is code for adjustable objective. That's where the parallax is adjusted. At the SHOT Show, I have met scope "manufacturers" who didn't know what the letters AO stood for or how it worked. Clearly not airgun scope makers! But better airgun scopes now have the parallax adjustment on the left side of the scope, and REALLY great scope makers also sell giant adjustment wheels for use in field target. Not all of them know WHY field target shooters want those big sidewheels, though, so I now see some scopes that only adjust down to 20 yards being sold with a large sidewheel. That's the equivalent of trying to sell a Corvette with a trailer hitch and a four-cylinder diesel engine! I think they believe the large sidewheels are a styling element.
Another good way to tell if a scope is for airguns is by the reticle. Every day I see more and more fancy and meaningless reticles pop up in the marketplace. The mil-dot is the current rage, and I hate it when someone buys one and then turns to me to explain how it works. I tell them of the military WORM formula used by artillerymen to measure distances on the battlefield, and they come back with something like, "But I want to use it to hunt squirrels!" Sure they do! They also want to use a full-auto Drozd running on air and a car battery to hunt squirrels, because that sounds cool, too. [Don't you DARE ask me for the plans on how to set up that gun!]
If the reticle looks like it belongs in a tank fire control system, it probably does. If the ballistic reticle is adjusted to 400 yards for a 180-grain Silvertip traveling 2,600 f.p.s., don't expect to magically adapt it to the trajectory of an 8.4-grain JSB Exact going 900. Airgun reticles are made for airguns, and they're either simple crosshairs, duplex crosshairs or some simple variation on that - like the Gamo scope I showed you last week. If you must have mil-dots, buy them and then experiment to discover what usefulness, if any, they offer you.
Scopes have changed radically in the past 15 years, and breaking them with an airgun is no longer the issue. Look for the proper parallax range and a good reticle. All other features are icing on the cake.