Short or zero eye relief scopes deliver a different experience to a conventional optic, so Mike Morton finds out what they have to offer.
It was a daytime shoot around the farm, and while the intended quarry had been feral pigeons, there seemed to be plenty of ratty activity going on near a long-forgotten stack of wooden pallets. One particular rat seemed bolder than its brethren, darting about like a mad thing, repeatedly scrambling over and under everything in its path in order to reach some tempting grain that had been spilled on the ground before hastily retreating to cover to devour each morsel.
This furious activity made it rather tricky to target the rodent, until for some unexplained reason it stopped dead in its tracks. The shot was on! Only it wasn’t.
By the time the rat had been picked up in the sight picture it was already scurrying back to safety.
This unfortunate scenario might have ended very differently had the scope in question been a short eye relief optic. But just what is this type of telescopic sight and what are its pros and cons?
To cut to the chase, a short eye relief sight will offer the shooter a far wider field of view than usual, which means they’ll be able to acquire the target more quickly. That’s something we’ll return to in more detail later, so for now let’s talk about eye relief first. As with any other telescopic sight, eye relief is the distance from the ocular lens to the shooter’s eye that lets them see the full viewing angle.
When you look through a scope you should have a clear sight picture from edge to edge. If you see any fuzziness or what looks like a black corona, this is a warning that the scope has not been mounted with the correct eye relief and needs to be repositioned either closer to or further away from the shooting eye.
Eye relief isn’t a set distance, but a range of distances, albeit a narrow range, because it varies with magnification, with a higher magnification setting requiring a shorter eye relief. And field of view, the crux of the matter here, will also affect eye relief, with a wider field of view also requiring a shorter eye relief.
So with a “short” or “zero” eye relief scope, the ocular lens needs to be positioned closer to the shooter’s eye than would be the case with a standard telescopic sight. However, because the scope is sitting so much nearer, it does mean this type of optic is not suitable for use on a recoiling rifle.
Anyone who shoots centrefire rifles may have witnessed, or even experienced, what happens when a scope is too far back on a recoiling rifle. On a trip to Bisley with a friend who had just bought a wonderfully blueprinted Remington 700, his gun fit and scope mounting had not been properly addressed. He insisted his scope had been fitted correctly, but his very first shot left him with a bad cut under his eyebrow. Much blood was spilt learning that lesson the hard way.
And that was with a conventional telescopic sight set up poorly.
Short eye relief scopes, as the name spells out, are intended to be mounted closer to the shooter’s face, so fitting them on a recoiling rifle is a definite no no. It’s always good to learn from other people’s mistakes, but curiosity often gets the better of us and I once decided to fit a short eye relief scope to a springer.
This rifle had been tuned and was very gentle to shoot. A pellet placed upright on the elevation turret of the scope it was currently wearing would stay in place whenever a shot was fired – a quick and easy test of a well-fettled rifle.
So if the rifle was as docile as this, surely it would be fine to replace the current sight with a short eye relief optic? No, it was not. There was no blood, but I nursed a painful bruise for several days. The lesson was learned this time round: short eye relief scopes must not be fitted to any rifle that exhibits recoil, be it spring or powder. They are for recoilless shooting only, so that means only PCP and CO2 rifles, and .22 LR and .17 HMR rimfires.
Vipers And SWATs
The concept of the short eye relief scope is typified by one of the earliest models to hit the airgun scene – the MTC Viper Connect. This optic originally came out in 3-12×32 format and while an even more compact model is now available, it’s still in production today.
It’s a scope I know well, having purchased an original model when they were first released, while I also have one of the more recent variants, typified by a matt rather than semi-gloss finish on the scope body and the addition of a small Picatinny accessory rail on top of the front ring.
MTC’s Viper Connect is an accomplished scope that has served me well for years. However, the sight I want to talk about here takes the short eye relief concept even further, as it’s the MTC SWAT Prismatic 12×50. While an ordinary scope relies on a series of lenses to transfer the light, the SWAT uses a prism to refract it, which means the body of the scope doesn’t need to be as long. So in addition to having short eye relief, this optic is physically short as well.
Despite their naysayers, bullpups and semi-bullpups have gained in popularity over the past few years, and that momentum shows no sign of slowing down. Shorter rifles tend to work well with shorter scopes, and short eye relief models, the SWAT Prismatic included, have found their way onto plenty of guns like these, where they are more in keeping in terms of their proportion and balance – both physical and aesthetic.
You may disagree, but I’m a staunch believer in the idea that if people like the way something looks, they’ll want to interact with it more often, and I suspect plenty of people will have chosen to mount a scope of this type based on its looks alone, regardless of the scope’s optical benefits.
But it’s also worth pointing out that a short eye relief scope will work with any recoilless air rifle, so feel free to fit one to your full-length gun if you want to.
Both the Viper Connect, which is a variable magnification scope, and the SWAT Prismatic, which is a fixed magnification optic, are unconventional designs, and while the Connect can be fitted with regular scope mounts
in a pinch, both of these sights are designed to work with purpose-built mounting systems.
The SWAT comes with three Picatinny bases of varying lengths to ensure the scope can be set up with the right amount of eye relief. Two adapters are supplied which fit inside the Picatinny mount so the scope can be used on rifles with a conventional dovetail rail as well.
Another nice feature rarely seen with airgun optics is the ability to loosen two screws on the mounting plate and angle the entire scope up or down, to keep the scope optically centred in elevation when zeroing the rifle at your chosen distance.
Whichever mounting system you use, Picatinny or dovetail, eye relief is critical, and even when it’s been set correctly it can be a little off-putting at first for anyone who’s not looked through an optic like this before. In the case of my Viper Connect, I have it set up so it just kisses my eye socket when I’m in the aim.
This definitely feels weird according to some of the people who’ve shot my rifle, but it’s just a case of getting used to something a little different. And in my case it offers a very distinct advantage – it ensures my head is in exactly the same place behind the scope for every shot I take, consistency being crucial to repeatable, accurate shooting.
While some short eye relief scopes use a standard ocular bell with the option to use a scope enhancer, the SWAT Prismatic is intended to be used with the rubber eye cup that comes pre-fitted.
For those shooters who can get along with them, scope enhancers do a great job of blocking peripheral light and helping the shooter concentrate on the sight picture. Some shooters, me included, do seem to struggle with scope enhancers, but luckily the SWAT Prismatic still works well with the rubber eye cup removed.
The SWAT series of scopes are all fixed magnification, the one seen here being 12x. Plenty of regular telescopic sights are also of fixed mag, the advantages being lighter weight, fewer lenses and therefore better light transmission, which means a brighter sight picture.
Short eye relief scopes of fixed magnification benefit from these features too, but with one significant additional advantage – a far wider field of view.
How much? I took a standard scope with a 50mm objective lens, the same as the SWAT Prismatic, and set the magnification at 12x.
I used a fairly basic, but nevertheless effective way of measuring field of view at my chosen zero distance of 30 yards, aiming at a central Birchwood Casey Target Spot and getting my buddy to place a marker at the periphery of my sight picture, then repeating the test with the SWAT.
The prismatic scope was the clear winner, offering a field of view of more than double that of the regular scope.
But the acid test wasn’t my shooting buddy, but my wife, who’s a bit of a reluctant shooter at best. Even she was impressed by what she was seeing and could immediately appreciate the benefits a scope like this has to offer.
Home In On The Range
All scopes are subject to parallax error – the apparent shifting of the crosshairs in relation to the target – and most scopes can be adjusted to correct for parallax error when shooting at different distances by turning a control mounted either on the objective bell or dedicated side turret.
Parallax error is exacerbated by inconsistent eye alignment with the scope and is more prominent at shorter distances, but can be “dialled out” using one of the above methods.
The lens configuration used in short eye relief scopes like the SWAT Prismatic makes parallax adjustment very sensitive, and it may even vary from user to user, so with this particular sight the parallax control has not been graduated with any distance markers. Instead, the shooter must point the scope at a target that’s been set out a known, measured distance away and the control adjusted until the target is perfectly sharp and in focus.
A waterproof range marker, which is supplied with the scope, can then be stuck on at exactly the right point to coincide with the witness mark on the body of the optic. This method may seem fiddly, but does offer a precise way of ranging a target as well as eliminating parallax error, and of course you can choose to range in either yards or metres.
Short Eye Relief Versus Long
Some of you may be aware of an alternative to short eye relief scopes, championed by a man called Jeff Cooper, a former US Marine, gun writer and firearms instructor. He’s best known for his work with handguns, but one long gun concept that he developed was that of the scout rifle – a fast-handling, do-anything firearm that was designed for quick target acquisition, having a forward-mounted scope with a very long eye relief.
The optics of the scout rifle, an example of which was brought to market by Austrian gunmaker Steyr Arms (but known as Steyr Mannlicher at the time), seems to embody the same benefits as the short eye relief scope – situational awareness and a wide field of view.
There’s one big difference though – the long eye relief required by the scope on the scout rifle means its level of magnification has to be kept low, while the short eye relief scope can have a much higher level of magnification, 12x in the case of the SWAT Prismatic seen here.
Right For You?
Is a short eye relief scope the right choice for you? Like so many things in life, shooting or otherwise, it depends on who you are and what you’re looking for. Traditionalists will probably discount them from the outset, and those shooters who are intrigued by this type of optic will have to contend with an unfamiliar mounting system, an ocular lens that’s closer to their eye than normal, and in the case of a prismatic scope the generally higher cost that’s encountered due to the production of such a specialised type of sight.
But those shooters who do embrace the concept will be rewarded with a package that offers smaller physical dimensions and less weight than a comparable standard scope, the option to have a higher level of magnification and of course that far wider field of view.
So if one of these scopes had been fitted for that farmyard sortie, that elusive rat might not have been so safe after all.
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