Your editor spent this morning acting as armorer/RSO at the annual pre-season sight-in shoot. As many of you know, several of my friends and I own a largish chunk of land that we have turned into a private range. Nearly every year since we bought the land, we’ve held a sight-in day in the run up to deer season.
This year was a bit later than normal, as deer season has already started in the northern tier of the state. The southern tier opener is next Saturday, the 16th of November. That said, the Adirondacks, which comprise most of the Northern tier, are difficult to hunt and have low deer density. The vast majority of the deer harvested in NY are taken in the southern zone.
All that said, the meat of this article will cover the basics of sighting in your scoped rifle, shotgun or muzzleloader.
First things first. Is everything tightened to spec and installed correctly? Double check the tightness of all the screws on your rig. And I mean all. Does your gun have action screws? Most bolt rifles do, and they have a torque spec. On Winchester M-70 and Remington 700 style actions, the value is 65 in-lbs, Savage recommends 30-35 in-lbs and Tikka/Bergara/Ruger American, 55-65 in-lbs.
Now check the scope base screws. They should be between 25 and 35 in-lbs regardless of style or manufacturer unless you have an aluminum receiver, then it should be 18-20 in-lbs. You can use a low strength thread locker like blue loctite on the base screws, however you should not use any thread locker on the ring screws. They should be dry torqued to 18 in-lbs and no more. Any tighter and you run the risk of damaging the scope tube.
Once you’re sure everything is correct mechanically, it’s time to sight that puppy in. If this is just a check of last year’s zero, go ahead and start at 100 yards. If you’re starting from scratch, fire your first shots at 10 yards.
All you’ll need is a couple of paper targets, some ear-and-eye protection and a safe place to shoot. A bench to shoot from is nice, as is a rest of some sort, but neither is truly necessary. A quick note about the targets, while you can use just about any old piece of paper or cardboard, a pre-printed sight-in target with a 1″ grid pattern can make it much easier to sight in.
Regardless of distance, the process starts the same: fire a group of 3-5 shots using the same point of aim. Do not try to correct your aim, you want to find out where the center of that group lands in relation to where you aimed. Once you’ve fired your group, it’s time to make your adjustments.
For the rest of this article we are going to assume the adjustments on your scope are .25 MOA, the vast majority of rifle scopes sold in the US are MOA with .25 minute adjustments. MOA, or minute of angle is equal to 1.047″ at 100 yards. If you have a milradian (MRAD) scope, you probably don’t need this article and think the whole thing is a bit simplistic. That said, the process is still the same even if the adjustments are different.
Let’s use this target as an example:
For now, let’s say this group was fired at 10 yards, we’ll come back to the 100 y group in a bit. The center of that group is about .5″ to the right of the vertical centerline of the target. At 10 yards 1 MOA = 0.1047″. That means you’d need to adjust your scope by turning the windage turret 20 clicks in the proper direction. At this point, I would fire another 3-5 shot group just to confirm. If that move brings the center of the group in-line with the vertical centerline, it’s time to move back to 100 yards and shoot again.
The elevation I wouldn’t mess with at the moment, point of impact should be high at 10 yards. If however, your group is near or below the horizontal centerline, I would move my elevation up.
Now, using that same group, but at 100 yards, here are the corrections you would need to make: two clicks left, 12 down. You could go 14 or 15 down, most people underestimate range in the field and that 1/2″ could make the difference between a clean kill and a 5 hour tracking job.
At this point all you need to do is fire one last group to confirm your zero and you’re good to go.