If you are new to rifle shooting, one of the most challenging aspects about setting up a riflescope is getting it on ‘zero’ quickly. But what is ‘zero’? Simply explained, it is the range at which you can ideally shoot quarry using the centre of your crosshair, without any hold-over or hold-under (or windage allowance). All rifle projectiles have a ‘trajectory’. The path of travel from muzzle to target. It doesn’t matter whether air rifle, rimfire or centrefire. Put very basically, this is an arc dictated by the weight and speed of the projectile (let’s call it ‘ammo’). The heavier and slower the ammo, the greater the trajectory (arc). The faster and lighter the ammo, the flatter the trajectory. This whole concept can be difficult for newbies to visualise. Hawke Optics, understanding this, grabbed an already established shooting ‘app’ called Chairgun which air rifle shooters had been using for years … and have made it even better. Whether you own a Hawke Scope or not, this app can be downloaded free from the Hawke web site.
The app allows you to plug in various ‘scenarios’ and work out what is the best zero for your chosen ammo, but there are some basic things you may need to set up first, such as reticle type and projectile choice in the top menu.
Don’t worry if you’re not using a Hawke scope (though if you do, this app makes life really easy). If you use a standard mil-dot scope, you’ll find it’s equivalent within the app. Next, adjust the settings in the top section of the graph screen. 1. Ammo weight in grains. 2. Preferred zero range. 3. Your guns power output if you know it (in ft’ lbs). 4. Height from barrel centre to scope centre. 5. The magnification you normally set your scope at.
Once you’ve set these, the graph below the settings will adjust accordingly. The green arc shows the expected path of travel as seen through your scope. In this case a 16 grain pellet zeroed at 30 yards in an 11.8 ft/lb rifle. The arc shows that at 9 or 10 yards, you can use the centre crosshairs. At 20 yards, you will need to aim a bit low. At 30 yards, back to the crosshairs.
To exaggerate this, look at the graph for my .17HMR rimfire. The settings are clear above. A 17 grain bullet with a muzzle velocity of 2550 feet per second. A 105 yard primary zero. The scope set at 12x magnification. As you can see from this, I can shoot a one inch wide target from 25 to 120 yards.
But Chairgun has another clever tool too, one I use all the time when calculating adjustments and zero changes to rifles. This is the Intercept Applet. For me, the most important feature of this great app. set up the usual parameters as described above, select the Tools menu from the top toolbar. Then click ‘View Applets’. Another drop down menu appears. Click on ‘Intercept View’.
This will bring up a screen that shows the view through your chosen scope / reticle type. This example shows my Hawke SR6 scope set at 30 yards. As you can see, if I want to shoot a target at about 40 yards, I would need to use the aim point two marks down. For 50 yards, four marks down. Simple.
All of these pop-up reticle views can be printed via the right-click menu, though you need to set the print size. There is also a scope cap print option which prints a circular view that can be cut out and stuck inside a flip-up scope cover. Again, you need to play around with the print-size options .
Personally, I use the Intercept View, sized down to approximately credit-card size. I then keep it in a self-laminating ID card holder, kept in my pocket while shooting. An instant range reference when needed.
Copyright Ian Barnett, Wildscribbler, Dec 2018
For the short-range rifle hunter (airgun or rimfire), using equipment like laser range-finders is often impractical … and un-necessary. Walk-about hunting doesn’t usually allow the luxury of employing a range-finder. We need to calculate range mentally and engage for the shot almost immediately, or the quarry will have gone. Remember, you will always have your brain with you when you go hunting, but not always a calibrated gizmo. Many of us ‘old hunters’ learned range judgement when Infra-Red or laser beams were the fantasy stuff of Marvel comics. To establish a mental range-finder takes practise; learning to attune your eye to object to brain co-ordination. Here are a few tips on how to learn to ‘snap-judge’ distance to target.
Learn to ‘pace’ not ‘measure’
All rifle shooting and subsequent adjustments for a shot due to different ranges are relative to the zero you’ve set. Learn to pace a yard, then five yards, then ten yards. For tall people, that will mean cutting their step. Short folk will need to stride out. Burn the tape measure once you’ve learned this. You won’t need it again. Now measure everything you target in paces, imagining how many steps away you are. If you zero your rifle to your own paces and learn to shoot over or under using the same ‘pace’ judgement you will negate the need for an electronic range finder while out and about. You’ll need lot’s of practise, which can be done all day, every day, until you are proficient.
Walk The Ranges
Most of us have to walk somewhere every day. This is an ideal opportunity to practise pacing out imaginary targets as you walk towards them. The next road junction, that parked car, the third tree from where you’re starting. Guess the distance and pace it out. If you got it wrong, stop and look back to where you started. I do this constantly while walking the dogs. Persist at this and you will soon fine-tune your mental range-finder … and it’s fun!
The Ten Pace Measuring Stick
In my book ‘Airgun Fieldcraft’ I explained how it can be easier to judge longer distances to targets if you ‘roll over’ an imaginary ten pace measuring stick in your mind. To practise this, focus on a point ten paces between you and a target some distance away. Imagine the ten paces as a ‘yardstick’ and imagine how many ‘ten pace’ yard sticks you could fit between you and the target. If it’s two and a half, the target is at twenty-five paces. Again, this takes some practise but once mastered can help judge distances out to fifty or sixty paces.
DIY Range Practise
The majority of hunters don’t have access to an indoor or outdoor range on which to practise. Yet if you have shooting permission on any land, you can create your own temporary range, at any time. Simply invest in a some metal knock-down or spinner targets. Use paper target holders or natural targets such as fir cones Pace out random distances (twenty-eight, thirty-five, forty-two paces) and learn how to hit them. Don’t forget to practise short targets too (eight, twelve, fifteen paces) as small vermin often pop up at close range. Keep a small bag full of practise targets in your motor … you never know when you might need to re-zero while in the field.
Check The ‘Failures’
You kneel to shoot a magpie sat on a fence post, but you miss. If you under-shot, you probably hit the post. If you over-shot, the pellet whistled over the birds head. Don’t ignore what happened. Pace out the distance from where you shot to the fence post. Check that you ranged it right (the magpie will be long gone!). If you did, the problem is with trigger technique, the scopes zero, your pellets or a loss of power. If you didn’t range it right, put a cone or a stone on the fence post and try again, go back to where you shot from and embed that range in your mind. Missing quarry isn’t always failure, it’s an opportunity to learn. Use that opportunity.
When Hunting, Range The Big Stuff
Mentally judging the distance to a small target like a bird or squirrel can be harder than ranging a larger object. So, if you can, use the nearest large object to snap-judge the range to your target. Perhaps a tree trunk, a game feeder, a gate post or a cattle trough. If the large object is twenty-five paces away and your squirrel is a pace in front of it, you know it’s at twenty-four paces. How simple is that?
Practise Random Shooting, Often!
Judging random distances to your quarry is one thing, shooting them at those ranges is another. Place natural targets such as pine cones or pebbles on fence posts or tree stumps and stroll away some distance without counting the paces. Just turning, estimating range and shooting them teaches solid range judgement and how to read your scopes reticule map. Better still, nothing gets hurt but your pride.
Not Everything Is Random
In a universe of chaos, there is a surprising amount of regimentation in the world around us. Anything created by mans hand is likely to have some calculated measure about it. The farmer will set his fenceposts five yards apart. The forester will plant saplings evenly spaced across the plantation, so the mature forest will have evenly spaced trees. Even telegraph poles are usually evenly spaced. Use these to measure range by counting along them to your quarry. Five, ten, fifteen, twenty yards (paces in your mindset). It pays, too, for you check ‘paces’ from regularly passed objects to others. This promotes ‘snap’ shooting. For instance, you may then already know the distance from the farm gate to the roof gable where the magpie is sitting.
This is similar to Pythagoras’ Theorem without the algebra. If you are shooting at a bird in the top of a tree, the distance from your muzzle to the bird is greater than the distance from you to the tree. But gravity will come into play, flattening the normal trajectory curve. I dealt with this in my earlier blog about shooting accuracy. The only way you master elevated range judgement is via constant practise on inanimate objects such as apples, pine cones and conkers.
Static Range Markers
If you’re setting up to ambush quarry (for instance, baiting corvids with a gutted rabbit), it’s useful to place distance markers beforehand. Once you know where you will be shooting from, perhaps a hillock or a bush, pace out set distances and place sticks in the ground at ten pace intervals to the target area and beyond if necessary. These help you to quickly judge the range of quarry, even if outside the ideal target area. This marking-out is best done a day or two before targeting a rabbit warren as your movement above will keep the animals beneath ground. The sticks will carry your scent for some hours. Another good reason to mark-up prior to your shooting day. If you are spot-baiting vermin, simply smear the bait species blood on the sticks. Ambush shooting is perhaps the one scenario where I will take my range-finder along (to set the range markers) … but if I have markers placed already, it will stay at home.
Shoot straight, shoot safe and keep the faith.
Copyright, Ian Barnett, Wildscribbler, April 2018