How To Sight In A Scope – The Ultimate Guide

You have thoroughly researched the entire rifle scope market, painstakingly comparing prices, features, pros and cons, all to pick out the perfect product for your weapon. Now you have a rifle and a scope lying in front of you.

Next you'll want to mount your scope to the rifle correctly and firmly, and sight your scope properly to ensure the most accurate shooting possible. After mounting your scope, you'll want to bore-sight your rifle, then zero in your scope at 25 yards and 100 yards.


This sounds easier than it is, and like most things, taking the time to do it right will pay off in the long run.

Proper Mounting Procedures

The majority of modern rifle scopes are designed and pre-fit to use specific mounting options. Before mounting your scope, or even purchasing your scope for that matter, make sure your rifle can handle the scope you've chosen. Mounting a scope made for a .22 caliber rifle onto a 30-06 could be potentially disastrous.

Bushnell Legend Rifle Scope

Make sure your rifle scope is designed for the type of rifle you are using, and double check the types of mounts and rings required by both scope and weapon. Once you have verified that your scope is designed to fit your rifle perfectly, you'll next want to mount your base, making sure to maintain as low a profile as possible without actually allowing physical contact between the bell and the rifle's barrel. Use a thread-freezing glue to lock down the screws of the base. This will help keep the scope in place over long use and exposure to continued recoil.

Align the scope's reticle, making sure that the vertical and horizontal elements of the reticle are perfectly vertical and horizontal. Make sure your eye relief, based on your cheek placement on the rifle butt and the rear lens of the scope, is set appropriately according to the scope's intended eye relief range.

Finally, tighten the screws carefully so as to lock the scope down perfectly with aligned reticle and perfect eye relief.

Bore Sighting

Once your scope is properly mounted and set to the perfect height and eye relief, you'll next need to bore sight your weapon before you actually sight in the scope. Some rifles, such as bolt action and single-shot varieties, are capable of being disassembled to a point that allows for a direct view from the rear of the gun, straight down the barrel of the rifle.

If this is the case, simply center your 100-yard target in the absolute middle of the round barrel. If you are unable to stare down the barrel, or want a slightly more accurate bore sighting, laser bore "collimators" are available. Bore collimators project a laser dot down the center of the barrel and onto your target.

Now that you have your bore centered perfectly on your 100-yard target, you need to set your scope to that point. Without moving the rifle (at all) adjust your scope so your reticle cross-hairs are centered perfectly in the center of the same target on which your barrel was just centered.

The most efficient way to accomplish this is to use a gun vise, which holds your rifle perfectly still and in place while you tinker with the scope. Many ranges will have gun vises available for your use, and they are worth the investment if you are planning on increasing the size of your own, personal armory over time.

Sight First to 25-Yard Target

Now that your scope and rifle are bore sighted, you can finally put some rounds downrange in order to sight in your scope as precisely as possible. There are a number of different ways to approach this task.

Hunting rifle scope

First, you can continue to use the gun vice while sighting your scope. This will provide a very accurate sighting, but the minute your body comes in contact with the rifle, the sighting will change; sometimes very slightly, sometimes quite considerably, depending on the shooter. If you are only planning on hunting with a bipod or tripod, this method might work for you. The basic concept of scope sighting is to attempt to mimic the same conditions in which you will be shooting on a regular basis.

The second method, and probably the most sensible for general/tactical purposes, would be to unsure that while you are sighting the rifle, you are also holding it the same exact way you would be if you were firing the weapon under normal conditions. Sandbags are highly recommended as a resting point for the front of the rifle, facilitating the required level of steadiness needed for zeroing your scope while still allowing for proper hand and shoulder placement.

Proper Technique, Windage, and Elevation

When firing your weapon, use slow, steady, and controlled breathing techniques. Most shooters will take a few full breaths, then one last breath, which they will allow half way out, holding the remaining breath for the duration of their aiming and shooting. Proper breathing ensures a steady rifle when the shot is fired.

Make sure to get a proper sight picture (perfectly centered and symmetrical image when looking through the scope) and sight alignment (align the sight picture/reticle with the centered target's bull's-eye). Obviously, this is a simplified explanation, and most shooters will practice for months or years to master these techniques.

Shoot three rounds at the target, in order to get a grouping with which you will be able to determine your adjustments (if necessary). If your shots are way off, you may need to actually adjust the placement of your scope on the rifle. However, especially if your bore sighting was done correctly, your grouping of shots should be fairly close to the bull's-eye.

If you are low, you may want to use your scope's adjustment turret up one or two clicks. Shoot another three rounds to see where you are now. Keep doing this until you consistently shoot a center, bull's eye grouping, making left/right (windage) up/down (elevation) adjustments with your scope.

Sight Next to 100-Yard Target

If you set your sights properly on the 25-yard target, you should hit almost exactly three inches above the bull's eye on the 100-yard target. This is because, at the 25-yard target, your barrel is angled ever-so-slightly upwards in relation to your scope, which is angled ever-so-slightly downwards.

When you then aim at the 100-yard target, the trajectory of your bullet is going to cause the shot to hit a little higher than the point at which you were aiming. This means your rifle is, for all intents and purposes, sighted in properly and you are now ready to go hunting, or target shooting, or storming a fortified bunker in a foreign land somewhere.

Tips to Remember:

  • Gun Safety comes First: You should never handle any weapon until you've taken an approved firearms safety course
  • Three-round Groupings: Three-round groupings ensure that you are shooting accurately, and allow for the occasional bad shot
  • Allow Cooling: Barrels heat up over time, and that heat can actually change the shape of the barrel and affect the aim of your weapon
  • Use Same Bullets you Always Use: Different bullets are different weights and contain different amounts of gun powder. Use quality bullets, and stick with a particular type
  • One Adjustment at a Time: If your grouping is low and left, adjust the elevation first, shoot three more rounds, and then adjust the windage