As we all know by now any lack of quality in our training, weapon, ammo or optics will not produce the groups we need to call ourselves expert marksmen.

In this section I will teach you the basics of a scope. I will explain all of their parts and functions. I will explain how to mount your scope to your weapon and how you can use a scope to find out the range to a target. So set back and let's see if we can tighten up your groups. 


All scopes will have a few of the same basic parts.

Objective Lens:

This is the lens at the end of the scope farthest from your eye. It will be sized in millimeters. The size determinds how much light can pass through the scope.

Adjustable Objective:

On a variable power scope this is a must but not all variable power scopes have them. When you zoom in and out your eye relief will move in and out. This will cause your stockweld (this is where your face rests against the stock) to move in and out. The adjustable objective can be focused to the range you are shooting. This will keep your eye relief and stockweld at the same spot. Most scopes have the adjustment ring on the objective lens. There are a few scopes that have it on the left side across from the windage turret.

Ocular Lens:

This is the lens that you look through. It is adjustable for your eye sight. All scopes come from the factory set for 20/20 vision. To adjust your ocular lens, loosen the locking ring. Site in on a big white background and adjust the lens until your reticle (crosshairs) is its clearest. Tighten your locking ring back down.


This is your cross hairs. There are many styles to choose from. Some have a ranging system built in. One of the best ranging reticules is the MIL DOT system. Another type with ranging capabilities is the duplex. We will talk more about these and others in the ranging section. The thing to remember is where the vertical and horizontal lines cross must be very fine for precision shooting. If the center of your cross hairs cover 1/8 of an inch at 100 yards, they cover a 1/4 at 200, 3/8 at 300 and a 1/2 at 400 yards. If you have a scope with a dot in the center that covers 1 inch at 100 yards this would be great for shooting at a deer at 300 yards because the kill zone would still be showing outside the dot. That same dot would cover a tack head at 100 yards. Your shot would be a guess.

Windage & Elevation Turrets:

These adjust your reticle for crosswinds and longer or shorter shots. Most new scopes have positive click adjustments. When you move the dials you can feel and hear the adjustment. This is the best type to have because you know just how much you have moved the dial. I have an old Leupold 4X scope that you move the dials around to the little tic marks(each mark is 1/2 inch at 100 yards)to adjust it. This is a great little scope but my groups always move around because there is an element of guess work as to just where the dial should stop. On the positive click dials each click is a certain amount of movement. These movements are measured in sub-minutes of angle or MOA. A minute of angle is very close to one inch at 100 yards(one minute of angle at 100 yards=1.047 inches). We will get into MOA a little later. This is divided into sub-minutes on your turrets. Depending on your scope, they will be 1/4, 1/3, or 1/2 of an inch at 100 yards. Anything bigger than 1/2 would not be advisable for precision shooting.

Zoom Ring:

On variable power scopes, turning this ring will adjust the power of the scope. On a 3X9, this will adjust from 3 power up to 9 power. Always remember to have it on full power when ranging.


The body or center tube of the scope. Most US scopes have a 1 inch tube. However most scopes that are military or police tactical made have gone to a 30mm tube. This allows more light which in turn allows better clarity of target. 

Basic types of scopes.

Variable power:
Is a scope that has more than one magnification. If you look at a target through open sights you are seeing that target at its original size. If you have a 3 by 9 scope, you can see that same target from three to nine times its original size.

Straight power:

Is a scope that has one magnification. If it is a 10 power scope, it lets you see the target at ten times its original size. 

Range Repeatability

What this means is as long as you do not make an adjustment to your elevation or windage your rounds will impact in the same spot.

Lets say you have been shooting at 100 yards all day and you dial in some elevation so you can shoot at 200 yards. After a while you want to come back to 100 yard and finish up the day.

It took one and a half inches of elevation for you to shoot at 200 yards. You dial your scope back to its original setting for 100 yards but now your rounds are impacting the target at a different spot than before.
Your scope has no repeatability.

Inside your scope are little gears or plates that move your crosshairs so you can adjust the elevation or windage. If your scope will not come back to its original setting these gears or plates are probably worn out.

Mounting your Scope

There are a few very important things to remember when mounting your scope to your weapon.

1st is quality mounts. When you fire your rifle, the recoil that you feel is also felt by your scope, mounts and screws. Screws will become loose and your scope will move.

Most experts now use screws called torx. You can get a better bite on these without striping out the heads. If your scope did not come with this type of screw, ask your firearms dealer for a set. They are well worth the small price.

When you mount the scope you need to have

Proper Eye Relief:

When you put your rifle up to your shoulder, there should be no dark edges around the outside of your scope. If you have to move your head back and forth, you have improper eye relief.

Your reticle is level:

If your reticle is not level your shots will follow that direction with range. Lets say you are canted just a bit to the right. As you increase range your shot will head to the right. If you dial in some windage your shot will move up or down. A simple way of leveling your scope is to set your rifle on its bypod or sandbags and look at your scope about 3 feet away. You can see your cross  hairs in the center with the edges of your scope black. Now turn your scope so that your vertical cross hair is in line with the center of your buttplate. After you have done this check your eye relief to make sure it did not move.

Bore Sighting

Bore sighting is just what it sounds like. You look through the barrel at an object and then adjust your reticle to the same object.

If you can not look through your bore after removing the bolt you will need to use a collimator. This is a device that you install in the end of your barrel. It has cross hairs and grid squares that you will line your reticle up to.

25 Yard Bore Sighting 

Place your rifle on a table at the 25 yard line of your favorite range.

A bypod and beanbag are a must. If you do not have a bypod, you will need to sandbag your rifle so it will not move.

Next remove your bolt and look through the bore. Move your rifle around until you see the target. I use an Outers 50 foot slowpoke pistol target. It has a 1 inch bulls eye that works great.

Once you have the target sighted in the bore, look through your scope. Now dial the reticle to the target, taking care not to move your rifle.

Once you have your bore and scope lined up, dial your scope down about 3 to 4 inches.

Move over to the 100 yard line and take your first shot with your new scope.

If you have done this correctly your shot will be real close.

Make your adjustments and finish zeroing in.

100 Yard Bore Sighting

Same as above except you are on the 100 yard line. I still use the same pistol target but once lined up, dial your scope up about 2.5 to 3 inches.

Mastering Your Telescopic Sight

The biggest obstacle you will encounter is your lack of time to train. With this in mind, focus on one particular aspect of marksmanship each session of training. This applies to all components of your weapon, optics and ammo, as well as the mental and physical aspects of your training. In this section we will only cover the aspects having to do with telescopic training.


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