Sighting-In Scopes On High Power Air Rifles
Here’s an issue that we have faced with increasing frequency at HAM in recent times. Sometimes it’s tough sighting-in scopes on high power air rifles.
As it can’t just be the HAM Team that’s been facing this issue, I thought it could be worthwhile to share how we overcome the situation.
Back in 2014 when Hard Air Magazine was first published, most air rifles were .177 caliber. True there were some .22 caliber guns about and a few .25 cals. But that was mainly it. 20 Ft/Lbs was a pretty good Muzzle Energy in most cases.
With these power levels being far less than today’s air rifles, it was easy enough to sight-in an air rifle at 10 Yards in our basement ranges. A pellet trap provided the backstop.
As air rifles become ever more powerful, the pellet trap was no longer a suitable solution, particularly with Muzzle Energies of 30 Ft/Lbs and above. This meant a move to outdoor shooting and sighting-in at a local range.
Below. The KalibrGun Cricket 2 Tactical delivers over 45 Ft/Lbs of Muzzle Energy in .22 caliber. We mounted a Sightron SIII 10-50×60 riflescope to take advantage of the long range accuracy.
The issue then is that the closest target that can be set-up on our local range is at 25 Yards. That’s a long way if you have no idea where a newly-mounted scope is pointing!
Yet more complication is provided by the presence of shrouds on the overwhelming majority of current air rifles – particularly PCPs. This means that it’s not possible to use a bore sighter – as would be the case with the majority of centerfire rifles.
Below. Even if the nut at the end of the shroud is removed, that’s still not the barrel you find. Forget bore sighting!
So what to do?
Basically, we focus on the scope…
If you buy a new riflescope, it may be set to its mechanical center – or not. If you’re mounting one that’s been used on another airgun, it definitely will not be!
So we center the scope’s erector tube using this simple method when sighting-in scopes on high power air rifles.
First rotate the elevation turret fully counter-clockwise until it stops. Then rotate it clockwise as far as it will go. Count the number of revolutions of the elevation turret from one extreme position to the other as you do this.
Now halve that number of revolutions and rotate the elevation turret back counter-clockwise that half number of rotations.
Repeat the procedure with the windage turret.
Now the scope will be (approximately) at its mechanical center. It should pretty-much be pointing directly at the target.
To be sure, we’ll mount the scope first on a low power airgun and see where the shots group on the 10-Yard range. At this stage, we’re looking primarily for windage differences. If the scope shoots pretty close to the center, we’ll make small windage adjustments until it’s dead on.
Then we’ll re-mount the scope on the high power gun – the one we’re testing, in our case. Now – when we get to the range – at least we know that it’s likely to shoot pretty straight, left to right.
At 25 Yards range, there may be some effect from wind, but it’s not likely to be enough to blow the impacts off of the paper.
That means that we can concentrate on finding the right elevation to get on the paper. Often, the mechanical centering process will have the scope producing hits somewhere on the target. If not, the impact splashes on the berm downrange can give an idea if you’re shooting high or low.
Below. We start aiming-in with the scope magnification set relatively low. Then increase magnification for final adjustment.
Of course, once you’re hitting anywhere on the paper, it’s a simple matter to adjust the scope so that the Point Of Impact is where you want. On the bull or thereabouts.
So that’s how we’re sighting-in scopes for high power air rifles at Hard Air Magazine.
It’s far faster than “spraying and praying” with more-or-less random elevation and windage adjustment until you get lucky and hit the target somewhere. It’s also more efficient on ammunition.