- All about scopes. Part 3. Sighting-in a scope in 10 minutes
All about scopes. Part 3. Sighting-in a scope in 10 minutes
By Tom Gaylord Now that you know how to mount your scope (see All about scopes, Part 2.) let's learn out to sight it in. Firearms are usually sight-in at 50 or 100 yards. They require the use of a device known as a collimator to align the scope with the bore, but that's not necessary when sighting-in an air rifle. We will start sighting at just TEN FEET, so there is no chance of missing the target paper.
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You MUST WEAR safety glasses, because you are going to shoot into a pellet trap at a range of just 10 feet. You will be hit by pellet fragments at this distance, so don't take any chances. WEAR SAFETY GLASSES AT ALL TIMES
The steps of sighting in are keyed to the photos. This whole procedure takes less than 10 minutes to complete.
Step 1. Draw one or two small dots on a piece of cardboard large enough to show where your pellets are going. I draw two dots about 2.5 inches apart and stacked vertically.
The target in the photo measures about 6 inches wide by 9 inches high, though it was cut roughly from a box. There is no precision to this step. You just want enough room on the target so no shots are lost. At 10 feet, they can't go too far. Hang this target in a safe bullet trap.
If your scope has parallax adjustment, adjust it as close as it will go. If it has variable power, adjust it as low as it will go. The aim point will still be a little fuzzy at this distance, but do the best you can.
Always aim at the top dot. Expect your first shot to be as much below the dot as the center of your scope is above your bore. If that's three inches, that's also how low the shot should go. My first shot landed low and to the left. I shot a second shot to confirm the first one. I'm not trying for a group. Step 2 After seeing where the first two shots went, I applied some right correction to the scope's horizontal adjustment knob and some upward correction to the elevation knob. At 10 feet it takes a LOT of clicks to move the next shot just a little way!
Shot three is in line with my aim point and just a little below the lower dot, so I'm finished at ten feet. Keep shooting and adjusting the scope until your shot lines up vertically. Step 3 Move the target out to 10 meters (or yards, it doesn't really matter). I shot two more shots and found I'd adjusted the scope too far to the right. This was corrected by adjusting the horizontal knob to the left. It doesn't take as many clicks to move the shot at this distance.
Step 4 One more shot shows I am realigned with the aim point vertically. Once the target is moved farther away, the shots will rise, but should stay pretty much in line from side to side. I like to have my shots land about 1.5 inches low at 10 meters, but this one is lower than that.
Step 5 Move the target to a range of 20 to 30 yards away. I moved it to 25 yards. As you can see, my group is very close to the aim point at this distance. That is a 5-shot group, and I am satisfied with it.
If I were sighting in this rifle to use, I would make some final small scope adjustments to bring the strike of the shots over to the aim point. If the shots are on the aim point at 20 to 30 yards, the rifle is sighted-in. It will shoot low from the muzzle out to about 20 yards. From there to 30 yards the pellet will move up or down so little that it will seem to strike in the same place, for all but the most critical shooting. This method works best for airguns shooting in the 800 to 900 f.p.s. range. At 900 f.p.s., the pellet will still be very close to the aim point out to 35 yards. Beyond 30 or 35 yards, the pellet will land below the aim point again.
Remember to wear those safety glasses at all times during this sight-in procedure. In fact, it's a good thing to do every time you shoot any kind of gun - pellet or firearm. It is especially important when shooting at the initial 10-foot distance, because the lead fragments will come back at high speed.