. Zeroing a rifle is actually fairly complicated. I am making this page mainly so more people will have a better understanding of what is really going on when you zero a rifle.

. The most important part is realizing that ALL weapons are zeroed at TWO different ranges. They are zeroed as the bullet is traveling up, and as the bullet is headed back down to line of sight.

. For example: The army standard rifle is the M4 Carbine. The sights are (approximately) 2.5 inches above the barrel. (I am using 2.5 inches for conversation's sake) They zero their rifles at 25 meters. Now what does that tell us? Since the sights are above the barrel 2.5 inches, then the bullet must climb 2.5 inches in 25 meters so that the line of sight (where you are aiming) and the point of impact (where the bullet hits) meet at the same point. Despite common belief, bullets do NOT raise or climb when they come out of a barrel. When you zero a rifle, you are actually aiming the barrel up, so in relation to the barrel, the bullet drops instantly as soon as it leaves the barrel.

. Now, the bullet has fired and has climbed 2.5 inches at 25 meters (that is the angle that the barrel is sitting at in relation to the ground). The climbing does not stop magically at 25 meters like it does in video games. Since you fired the bullet upwards, it is going to continue flying upwards until it begins to lose speed and starts falling back down to earth. If you zero an M4 at 25 meters, and the sights are 2.5 inches above the barrel, then guess where the bullet will hit at 50 meters? Just a little shy of 2.5 inches high due to gravity already pulling the bullet down. At 100-150 meters the bullet will impact about 6 inches high, and from there on out it drops more and more until finally coming back down to the line of sight at 300 meters.

. So, by zeroing at 25 meters you have also just zeroed at 300 meters.

. Keep in mind that every gun will not shoot the same. Let's say you have an AR-15 with a scope that is 5 inches above the barrel. What would happen if you zeroed it at 25 meters? The bullet would then have to climb 5 inches to reach the line of sight as compared to 2.5 inches. So what? Well, this means that the angle of your barrel is now TWICE what it was with iron sights and will shoot nowhere near where your irons sights are hitting at. (It will hit fine at 25 meters, but anything past that it will hit rediculously high. I'm talking "feet" high.)

. What if you zeroed with your scope 5 inches above the barrel, and made it shoot 2.5 inches lower than dead center at 25 meters? Then you will have duplicated the bullet flight path of your zero with the iron sights, EXCEPT for the whole 300 meters it will be shooting 2.5 inches lower than with the irons. Is this making sense to anyone?

. I just wanted to throw some food for thought out there.

. Remember that every gun shoots different, and if you aren't sure what range to zero at or don't have the means to test it at long range, remember that a 50 meter zero is pretty generic for most any gun. It will work for most hunting rifles and most assault rifles. If you have an AR-15 with iron sights, or an optic that sits close to the barrel, then I recommend using a 25 meter zero.