Zeroing my Sport II

[Dave270]

Just got my M-15 Sport II and am going to the range Monday to zero it.. If I remember right, back when I was in the military, we used to zero the iron sights at 25 yds., and that was our "battlefield" zero out to 250 yds.. My question is, using the Sport II iron sights, is the 25 yd zero still the preferred distance to zero the iron sights..???? Any suggestions would be appreciated...

Dave

 

[OKFC05]

Fill in the blanks in this handy ballistic calculator, and pick your own trajectory. You'll see that sight height above bore is critical.
Handloads.Com Ballistic Calculator

 

[blues7]

Just got my M-15 Sport II and am going to the range Monday to zero it.. If I remember right, back when I was in the military, we used to zero the iron sights at 25 yds., and that was our "battlefield" zero out to 250 yds.. My question is, using the Sport II iron sights, is the 25 yd zero still the preferred distance to zero the iron sights..???? Any suggestions would be appreciated...

Dave

Hi Dave,

If you shoot from 25 yards you can achieve a 100 yard zero by adjusting your sights so that your point of impact on the target is 1.5" below your point of aim.

The beauty of this is that you will be dead on at 100 yards, and only need to hold over a maximum of 2.5" from a distance of zero on out to 200 yards.

Here's an excellent short article on the topic which explains the process very clearly and includes a very informative table at the end.

Also, this video shows the same concept of having the point of impact ~1.5" below point of aim at 25 yards for a 100 yard zero. (The video is demonstrating the zero with an Aimpoint but the concept is the same.) Toward the end of the video the Aimpoint representative shows some illustrations of where the point of aim would be at various distances using this zero. It's very informative.

How to Zero Your Aimpoint - YouTube

 

[MMT]

A 50 yard zero is most common, the 25 yard zero allows you to shoot further distances before you need to hold over the target. The 25 yard zero lets you be zeroed at 25 and 300(ish), the 50 yard zero is zeroed at 50 and 200(ish), the advantage of the 50 yard zero is that it gives you less offset to deal with within than the 25 yard zero [for shots in between 50-200ish the impact will be higher with the 25 yard zero].

 

[SCAR333]

Does this apply to all grains of bullets, or specifically for a certain grain bullet (55gr, 62gr, etc...)?

 

[MMT]

It applies for all bullets, the velocity of each particular load and BC of the bullet will cause the second distance the rifle is 'zeroed' at to change slightly. The reason for this is the mechanical offset of between the optic or sight and the bore.

 

[Tbat]

A 35, 50 or 100 yard zero works best for what most people shoot at, but as said it depends on what you are wanting to do with your rifle. As was said above the 25/300 yard zero will allow you to stretch out your range with less hold over, when shooting past 300 yards.

The downside of a 25/300 yard zero is that you have more hold over/ hold under information to remember. With a 25/300 yard zero you will be shooting 6 to 9 inches high at 200 yards (basically on at 25, high at 100 and 200 and back on at 300 or so). With a 35, 50 or 100 yard zero you will have a flatter bullet trajectory out to 300 when compared to the 25 yard zero and be pretty well on target at 50 and 200ish as stated above.

With a 50 yard zero you will be roughly no more than 2 inches high or 2 inches low clear from the muzzle out to 225 or maybe even 250 yards, depending on your load. However you will have more hold over past 300 when compared to the 25 yard zero. With a 100 yard zero you will have an even greater hold over past 300 yards.

Different grain bullets, powder loadings, and even the barrel length can affect the numbers somewhat, but sometimes not as much as you would think that they would.

 

[Tbat]

If you want to zero at 50 yards and don't have a 50 yard range, you can achieve it at 10 yards, by adjusting your shots to hit 1.9 to 2 inches below the point of aim at 10 yards. Check out Frank Proctor at Way of the Gun on youtube, [ame]https://www.youtube.com/watch?v=P-FUsH8jt6E[/ame] It works I have tried it myself with a couple or recent AR15 purchases.

 

[stwings]

A 50 yard zero is most common, the 25 yard zero allows you to shoot further distances before you need to hold over the target. The 25 yard zero lets you be zeroed at 25 and 300(ish), the 50 yard zero is zeroed at 50 and 200(ish), the advantage of the 50 yard zero is that it gives you less offset to deal with within than the 25 yard zero [for shots in between 50-200ish the impact will be higher with the 25 yard zero].

For iron sights, I like a 50yd zero. When aiming center mass at human sized targets you will score a hit from any distance out to 300yds without worrying about hold over/under's.

 

[vonn]

No matter what range you zero at you should put some time and ammo in at other ranges to learn what your gun / load does at that range .