"Zeroing" your hunting rifle
Zeroing your hunting rifle
Talking to customers coming into the shop, other shooters over past years and also reading some of the current “expert” how to advice on the internet now, I see that more and more confusion is out there about what sighting in a hunting rifle actually means and how to do it.
Many use the term “Zeroing” rather than sighting in. most use this term to describe adjusting your scope so that the point of impact is at a zero point (dead center of target) at a known distance (usually 100m).
This works really well if you’re just shooting at that known distance, such as at a range. It also works for those with the necessary knowledge, skills and equipment to adjust their scope for trajectory change at other distances (notice I didn’t say drop, because closer than that zeroed range bullets will hit higher than the zero point).
This was previously the domain of long range target shooters, but the increasingly popular long range hunting trend requires shooters to adjust for different distances. In both examples, the shooter will have worked out ballistics and drop, will have practiced at those ranges, and in actually taking the shot has time to check the range, consult their drop tables (and windage) and adjust the sights accordingly.
But what the average NZ hunter, that doesn’t have all that gear or experience, or the great majority of hunters that typically stalk in our forest parks, in bush or around bush edges (or even those that stalk smaller game on farms etc with 22’s).
How often do guys “zero” at 100m then “hold over a bit’ when they think the animal is further away? And how often are they missing (probably never know because they never say) because the bullet has gone completely over the animal.
I still have a very old copy of the original Mountain Safety Council NZ Firearms Handbook (written by Lynn harris) which talked of Maximum Point Blank Range Max PBR.
Point Blank Range is usually thought of to as being so close you simply aim in the middle and don't need to worry about bullet drop.
It recommended sighting (or zeroing) your rifle in so that at 100m the point of impact was approx. 3” high, this would give you a maximum point blank range well out to nearly 300m depending on what cartridge you are shooting and what size game you’re going after (obviously a rabbits kill zone is much smaller than a red deer).
The above pic illustrates the concept, obviously the actual figures (heights, kill zone, distance) are all dependent on what you are shooting and hunting.
Here’s some examples of Max PBR based on sighting in 3" at 100 yards (about 75mm at 90m - sorry it comes from an american source)
- .243 Win/100 grain = 283 yards
- .257 Wby Mag/120 grain = 317 yards
- .270 Win/130 grain = 294 yards
- 7mm Rem Mag/150 grain = 305 yards
- .30-30 Win/150 grain = 225 yards
- .308 Win/150 grain = 267 yards
- .30-06 Spfd/180 grain = 263 yards
- .300 Win Mag/180 grain = 290 yards
If your favourite rifle/cartridge combo isn’t listed you can work yours out here http://www.shooterscalculator.com/point-blank-range.php
What this means that shooting at a deer, the hunter only needs to aim at the centre of the heart lung area, and anywhere from virtually the end of the rifle to about 300m the bullet would impact in this kill zone.
Most deer in this country are still shoot under 100m, so this means as a hunter you don’t need to adjust your aiming point at all for almost all of your hunting.
Many scopes have hold over dots, so with a little practice at the range you can work out that holding the first or second dot will give you a 300/400 etc kill shot.
The net result of this for your hunting is likely to be far less missed shots at closer ranges, and also more success out at longer ranges out to 200m odd, which is actually quite a long way.
Theres plenty of articles on the net to explain this in more depth, and also a number of ballistics calculators that will help you to determine what the MPBR for your rifle/cartridge/target combination is.
Yes , the calculators will require a bit of knowledge of velocitys and Bc’s but that can be easy to find, and you don’t need it exact.
Here are some you might like to check out
I hope that helps you at the range when sighting in, and also to put more meat in the freezer