How to easily sight-in an air rifle
by B.B. Pelletier
This post was inspired by a Pyramyd Air customer who recently returned a LaserLyte boresight device because it was 5" off his aimpoint at 30 yards. I was flabbergasted that he got AS CLOSE to the mark as 5" at that distance! He thought he should be CLOSER?!
Laser boresight devices are supposed to align the bore of your rifle with the sight line of your sights. They can get your rounds ON PAPER at 100 yards! They ARE NOT supposed to zero your scope.
When I was in the Army, I used to boresight 105mm M68 cannons on M60A1 tanks, because the "paper" (actually a huge 12-foot square plywood sheet) sight-in target was 1,200 yards away. With those monster rifles, we didn't have the luxury of shooting at a small target at closer distance. Our normal targets were positioned 1,500-2,500 yards away, so 1,200 yards was considered close. We used black thread in a crosshair pattern over the 4" muzzle and binoculars to look through the barrel from the breech. When we fired, everyone on the range helped us by watching through binoculars to see where the tracer went. The inert aluminum practice round left a perfectly circular hole in the plywood. If you saw where it went, it was easy to see the resulting hole through a 10x scope. The ammunition was expensive, plus it wore the bore rapidly, so we didn't want to shoot more than necessary. The goal was to hit within a 24" circle at 1,200 yards and to take as few rounds as possible to get there.
With firearms, you may have to boresight
With a centerfire rifle, I may use some kind of boresighting method to get on paper at 100 yards, but not always. Sometimes, I start sighting-in on a 50-yard or even a 25-yard range just to make things easier. Because the target paper is closer, the bullet has a greater chance of impacting somewhere on it, especially at 25 yards.
On some days, the range is full of shooters and I can't move between targets at different ranges. I have to sight-in wherever I happen to be. If I'm unlucky, I find myself on a 100-yard range with a rifle I've never shot and the target paper I'm shooting at is only 12" square. Only dumb luck would get me on paper under that set of circumstances, so I'll use a laser boresight device if I have one. Or, if the rifle is a bolt-action, I'll remove the bolt and sight through the barrel by eye. When both the reticle and the bore seem to be pointing at the target, the chances are good the bullet will hit somewhere on paper. What if it doesn't?
A field expedient for sighting-in
The best field expedient to get on paper at long distance is to pick a spot on the dirt backstop berm that you and a friend can both identify - you looking through the scope or open sights of the gun and your friend looking through binoculars. Aim at the spot and both you and your friend call where the shot actually strikes. Adjust the sights from there. If you hit low and to the left of the aimpoint, adjust the scope or sight higher and more to the right. As long as you can agree on the aimpoint, this should take just one shot, or two at the most.
But airguns are different
Airguns aren't centerfire rifles. They don't have more than a small fraction of the danger range, so they're much easier to sight-in. You don't need a boresight device; you just need a cardboard box and 10 feet of distance. Tape a small target with a dark central aimpoint to the box. At 10 feet, it doesn't take much to get on a small piece of paper. I use 10-meter pistol targets that measure 8"Hx7"W. Except for a Bug Buster, no scope is clear at 10 feet, but that doesn't matter, and the aimpoint is way too large, too. But, you can still see the aimpoint well enough to align the crosshairs.
If you don't have real target paper targets, don't use copier paper. It's terrible. Use a piece of cardboard or tagboard that will leave a visible pellet hole. I used cardboard for the sight-in article I wrote. At 10 feet, you want your pellet to strike the target directly below the aimpoint of the scope. How far? By the height that the sight line of the scope is above the bore. The height of the scope above the bore determines how far below the line of sight the pellet will strike AT CLOSE RANGE. Sighting-in is the process of making these two lines converge at some distance. Think about that. If the muzzle were touching the target, that's how far below the scope's line of sight it would hit. Backing up to 10 feet just gives the scope a little chance to focus on the aimpoint. Then follow the rest of the directions in that article.
Special airgun problems
Sometimes, I'm not sighting-in a .177 - I'm sighting-in a .45 caliber big bore. And, I'm at the range by myself (I belong to a private range and I'm often the only person on all four ranges). You don't sight-in a .45-caliber, 500 foot-pound air rifle at 10 feet!
I recently had this problem, and didn't have time to start on the 25-yard range, so I used a 4-foot-square piece of cardboard cut from a flat-screen TV box as my sight-in target on the 50-yard range. Believe it or not, there were still problems hitting that big target square at 50 yards (I didn't know what bullets shot well in the rifle I was testing), but I solved them by aiming at the extreme corners of the target cardboard. Finally, one shot printed about three feet low and three feet to the right. That told me two things - the bullet I was using was wrong for the gun, and I would need gross scope adjustments if I wanted to use it. That sight-in session failed because I couldn't find a good bullet of the six types I had available that day. The next time out, I found the right one and got 1" groups with it. The point is that sometimes you have to improvise. You couldn't do what I did on a busy public range, but you could do the berm trick with a friend.
Sighting in airguns is a breeze, if you use the smaller scale of the guns to full advantage. Yes, it's cool to have all sorts of high-tech gadgets in your range bag, but sighting in isn't a high-tech exercise. Remember to play safe and always wear safety glasses, and your sight-in sessions will go on without a hitch.