Modern sporting optics
Steve Rawsthorne highlights some of the recent advances made in sporting optics technology, and explains why it's a good idea to spend as much as you can afford on a rifle scope for stalking.
Over the last 20 years, and at an increasing pace in the last five, there have been huge developments in rifle scope technology, along with a noticeable hike in the price of top-end optics. But what is just marketing hype, and what is of real practical benefit to the hunter?
The basics of what we need as a rifle hunter have not changed over the years. There is a trend now towards longer range shots, and several of the major manufactures are offering bullet drop compensators (BDCs) or ballistic turrets, and then there are the out-and-out tactical target scopes, either in minutes of angle, (MOAs) or Mils, (milliradians) with reticles in the first or second plane. Glass and the coating applied to it have also been vastly improved, allowing us to shoot later into the evening or earlier in the morning.
As a woodland stalker, most of our stalking will take place at first or last light, so light-gathering ability is vital to make the most of our opportunities. This is where the premium brands – Swarovski, Zeiss, Schmidt & Bender and Leica – really score. They quote light transmission rates in excess of 90 per cent for their top-end scopes, but you will have to pay for this quality, certainly in excess of £1,500, and possibly as much as £2,000.
A scope is subject to huge forces every time you squeeze the trigger and it needs to be built to withstand this. Top-end scopes have steel gearing – what moves the reticule to the left, right or vertically – while cheaper, lesser quality ones have gearing of softer brass or even plastic, which will not last as long or even hold zero.
The coating applied to lenses has developed hugely too; they can be fully coated, fully multi-coated or multi-coated. The coating on a lens affects its light transmission rates and ‘flare', the distortion around an image. Years ago, lenses had a single coating of magnesium fluoride applied to one surface of the lens. Today's premium scopes have computer controlled and applied multi-layer coatings applied to both surfaces of the lenses to give you the crispest, most distortion-free image possible and allow you to shoot for those extra golden minutes at last or first light and in the most adverse weather conditions.
The hill stalker tends to stalk during the day and to shoot over longer ranges. As a result, the light-gathering abilities of a scope may not be as important, and some form of bullet drop compensator may be of use. Everything else in terms of quality of manufacture applies as above.
The next thing to consider is objective size and magnification. As the level of magnification increases, the light transmission decreases and the field of view shrinks in size. In practise, this means that in poor light we want to use the minimum magnification necessary to make a clean shot, so we have the widest, brightest image available. Years ago, snipers made do with 6x42 scopes, a magnification of six and an objective lens of 42mm. Nowadays, the military around the world have taken the best of sporting scope technology and adapted it to their use, so sporting and military scopes now drive developments in scope design and feed off each other. As an example, the British sniper scope is an S&B Police Marksman II with a variable power of 5 to 25 and an objective lens of 56mm with an illuminated reticle. For most hunters I would recommend an objective lens of 50 or 56mm and a variable magnification of 2 to 12. This will allow you to shoot in all light conditions and out to 300 yards, assuming you are capable of that. The very low magnification means you could use the scope when on a Monteria or driven boar shoot or in a high seat at night for boar.
As a stalker with just one rifle or one scope and several rifles, hunting across a range of species and times of day, we want a scope with one piece construction (i.e. the tube is machined from one piece of metal, not two or three screwed together), fully multi-coated lenses with high light transmission rates and steel gearing. Spend as much as you can afford and then a bit more! You could buy one premium scope such as a Swarovski, Zeiss or Leica with a bullet drop compensator and fit it with quick detachable mounts then have multiple zero points on the turret for the different rifles/calibres, switching it between them with no loss of zero, which makes it very cost effective. An objective lens of 50 or 56mm and magnification of around 2 to 12, from a premium manufacturer should cover all the options. So much for the basics, now we come to the bells and whistles!
The first desirable extra on my list would be an illuminated reticle. I know some people suggest they lead to stalkers taking shots when they shouldn't, but when you have a dark fallow standing against a wood at last light, the ability to see clearly where your crosshairs are is invaluable. Turned up to its brightest and coupled with the low magnification setting on your adjustable scope, it's great for running boar or turned down low if sitting in a kunzle in the moonlight for the same boar.
Recent developments from Swarovski, Zeiss and Leica include motion sensors, so that when you lay your rifle down in a seat or stand it on its end in a kunzle it automatically switches off to preserve battery life, but automatically turns back on to the setting you left it at when you pick it up and take aim. The new Schmidt & Bender Stratos and the Zeiss V8, not available in the UK, have programmable reticles – plug them into your PC via a USB cable and off you go. I personally am a fan of the Swarovski Z6 version where you set your day and night levels to suit your needs.
At a 150 yards, the drop on an average calibre bullet, such as the .308 Win. is insubstantial when zeroed at 100 yards, at 200 its about 2", at 250 it is around 7 or 8", at 300 it is 12" and at 400 it is around 29 or 30". These are for a 165gr softpoint, but most deer legal calibres will be fairly similar. When I shoot my .308 tactical rifle at Bisley at a 1,000 yards, the drop is around 36ft(!). You obviously can't aim off that amount, so you need something more precise. Let me say now that I am not advocating long range shots on deer or other sentient animals. I limit myself to 300 yards. Even so, a bullet drop compensator takes the guess work out of such a shot so you can be more confident of a clean kill.
BDCs are a development of tactical or target turrets. A sniper or target shooter would establish the distance to the target and then by reference to a ballistic program or chart, dial in the required elevation to compensate for the bullet-drop, either in minutes of angle, (MOA) or mil-rads, (MRAD or milliradian). Actually, the harder part is allowing for windage and, if there is much cross wind, you are better off not taking a shot at extended ranges.
For the stalker, a simple to operate system is a boon, where you just turn a turret to the desired range and shoot. First, you need to establish accurately the range to your deer – a laser range finder is essential, I have binoculars with a built-in range finder, rather than carry two separate bits of kit – then just dial in your range. Zeiss have their ASV system on the Victory HT range of scopes and Leica have a similar system. Basically, you zero your rifle at 100 yards and then go to a ballistic program on the manufacturer's website and input the bullet weight, ballistic co-efficient, barrel length, height of the sight above the barrel and speed of the bullet. To get the speed of the bullet accurately, you will need a chronograph and the use of a range. Once you have done this, you should go to a rifle range and test the scope/turret/bullet combination at the ranges you have set it up for. Do not, under any circumstances, rely on the program to shoot at anything live until you have tested it thoroughly on a range. As with any computer program, garbage in = garbage out, so you owe it to your quarry to do this properly.
Although it sounds complicated, if you read the manuals and do it properly, it's not difficult. I recently bought a Swarovski Z6i 2.5-15x56 with a ballistic turret to fit to my custom 7-08 rifle. I downloaded the program from the manufacturer's website and input the data required. I had the choice of various standard factory ammunition or inputting my own hand load data, which I did. I zeroed the scope at 150 yards on the range at work and then set up the rings as directed by the program and manual for 200, 250 and 300 yards. The next day I was at Bisley and went straight to 300 yards and the first five rounds went straight in the bull. Down to 200 and exactly the same result, so now I would be happy to shoot a deer with it, but only after I had tested it properly. Bear in mind that if you change your bullet weight, manufacturer or add or remove a moderator, you will have to do the whole process again. You need to have a zero stop function on the BDC, so that you can turn it back to the zero range without fail.
Some manufacturers produce scopes with a ballistic reticle, so that there is the normal cross hair with several stadia lines below it. Again, you need all the information about your chosen ammunition and the manufacturer's program. Input this and it will give you the distance the stadia lines correspond to for that round at one magnification unless the reticle is in the first focal plane, in which case it will apply across all magnifications. I have a 2-12x50 scope with a three stadia reticle which, at 12x gives me 250, 300 and 400 yard hold points for my particular bullet. But if I reduce the magnification, the point of impact changes dramatically, by up to several feet. If I set my magnification to 12x, know the range to my target, I just hold the corresponding line on it and away we go. Simple and intuitive to use.
Tactical or target turrets come in two measurements, either minutes of angle, basically 1.047 inches at a 100 yards, or milliradian, often referred to as MRAD or mils, which are 1/1,000 of the radius to the target, or one metre at a thousand, one yard at a thousand, etc. You need the aid of a ballistic program and all the data previously described. From this you can model the trajectory of your bullet and so what the compensation is at various ranges in either mils or MOA. If you have a mil-dot reticle, you want to have your scope turret graduations in mils – don't mix mils and minutes, it just adds a further layer of calculation and potential error. There are all sorts of types of reticles – Horus and Nightforce have their own versions. Unlike a BDC, you need to either memorise the range/compensation or have a little card stuck to your stock. A zero stop function, where when you turn the turret back as far as it will go returns it to your zero position, is vital, otherwise in the dark or heat of the moment you can lose your base position.
A reticle in the first focal plane grows in size with the target as you increase the magnification on a variable scope, so it is constant at all ranges and magnifications. One in the second focal plane remains the same size as magnification changes, so is accurate only at one magnification. For a standard crosshair, this makes no difference, but for mil-dot reticles and similar designs, it is much simpler and safer to have the reticle in the first focal plane. Mil-dots are best left to snipers and long range target shooters. For a hunting scope, stick with a ballistic turret or ballistic reticle. When that huge buck appears before you, you don't want to break out your smartphone and start making calculations!
Before you go out to shoot at longer ranges, learn to shoot at a 100 yards. A 4" group on the range at 100 yards is a 12" group at 300, and that's without adrenaline and some hard breathing. Only when you can consistently shoot four-shot 1" groups at a 100 yards, are you ready to consider longer range shots. We owe it to any animal we shoot at to kill it cleanly, so time on a range and practise are crucial. Remember, good technique comes from practical experience.
If you are going to use all the technical aids available, read the manual, so that you understand how it works and take the time to set it up properly and again, practise on a range. When you can consistently shoot 4" groups on the range at 300 yards, you can start to think about longer shots in the real world.
In conclusion, spend as much as you can on optics and then a bit more. If your budget is tight, buy a fixed power premium scope – a 7x50 or 8x56. You can often pick up a second-hand bargain on the gun sales websites. But don't compromise on quality and buy something which looks “tacticool” but will not live up to your expectations.
If you can afford to spend a bit more, go for a variable power scope with an illuminated reticle. If you want to push the boat out, then a ballistic turret is worth having but only if you are prepared to put the range time in and learn to use it – it definitely does NOT give you the ability to take longer shots, so be prepared to burn some ammo. On the other hand, you could just stick to shots under 200 yards and spend time honing your stalking skills.