25 Yard zeroing

[jakeman]

Ok, so I'm going out tomorrow to zero my new AR with iron sights. I'm starting out at 25 meters with a 25 meter zeroing target. My question is should I startoff with my front sight post as is from the factory or should I bring it down level with the front sight base as someone suggested?

[zero7one]

Start with a battle sight zero (BSZ). Start with your front sight post flush with the base. Then take your rear sight and turn the windage knob until the aperture is all the way to the left. Now count how many clicks it takes to get all the way to the right. Divide that number in half and go that many clicks back to the left. That will get you as true center as possible without having to relying on the index lines.

Good luck, be safe, and have fun.

[jakeman]

So after I do this do I just align my rear sight with the top of the front sight base when I fire my first 3 to 5 shots?

[zero7one]

Yes. Align the top of the front sight post in the middle of the rear aperture. I would suggest that you stick with 5 round sets to ensure you are getting tight groups. Absolutely no less than 5. When you are getting all of your 5 rounds inside about a 2-3 inch circle, you can make your adjustments. Make sure that you shoot 2-3 5 round sets before you start to make adjustments. You first need to confirm that your fundamentals are in place. Note: 2-3 inch groups are just a suggestion. Some prefer tighter groups, while others are willing to settle in something less strict.

Once you determine if you need to make some adjustments remember that if you need to move your rounds down, raise your front sight post up. If you need to move your rounds up, lower your front sight post down. If you need to move your rounds to the right, move your read aperture to the right and vise versa for the left.

[Quib]

Jakeman,

This tutorial might help with zeroing....http://www.weaponevolution.com/forum/showthread.php?1713-AR15-SIGHT-ADJUSTMENT-BASICS

If you'd like a copy of the Army Marksmanship manual, just drop me an IM with your email address.

[jakeman]

Yes. Align the top of the front sight post in the middle of the rear aperture. .

Well I guess I am confused. If I lower my front sight post flush with the base, how can I align my rear sight with the post?

[Paulo_Santos]

Well I guess I am confused. If I lower my front sight post flush with the base, how can I align my rear sight with the post?

Check out the link that Quib posted. It is really helpful. You don't turn the front sight all the way down for a Battle Sight Zero. You turn it down or up until the BOTTOM of the front sight post is flush with the front sight base, like in the picture.

[Quib]

Give me a minute to post an illustration.......


ETA:


http://farm5.static.flickr.com/4109/5064291993_9f77b25bff_z.jpg

[Quib]

If that is not clear enough let me know. I'll see what else I can put together.

ETA: That offer still stands if you would like a copy of the Marksmanship FM sent to you. [:)]

[Quib]

http://farm5.static.flickr.com/4107/5065017404_24c780c622_z.jpg

[jakeman]

Ahhhhh I see, sorry I didn't have my coffee yet when I first asked this. I was thinking top of post flush with base. Thanks to all you have been very helpful.

[Quib]

Glad to help. [:)]

[John Hwang]

Tell me if this isn't the most informative AR15 site without the drama? Great info as always guys.

[Quib]

http://farm5.static.flickr.com/4145/5067327825_bb7742287e_b.jpg

[woodwrkr]

Hi, first time posting here. I'm new to AR's but not new to shooting (I built my own 1911 from the ground up about 6 months ago). I'm going to be zeroing my first AR in a couple of weeks as soon as the barrel arrives. Can an AR be "bore sighted" in the same way as a bolt action rifle? In other words, separate the upper receiver from the lower with the BCG removed, set the upper on sand bags with the bore perfectly in line with the target and then adjust the sights to be in line with the target? Will this save some ammo or time? Or should I just follow whats posted above?

Thanks.

[zero7one]

Hi, first time posting here. I'm new to AR's but not new to shooting (I built my own 1911 from the ground up about 6 months ago). I'm going to be zeroing my first AR in a couple of weeks as soon as the barrel arrives. Can an AR be "bore sighted" in the same way as a bolt action rifle? In other words, separate the upper receiver from the lower with the BCG removed, set the upper on sand bags with the bore perfectly in line with the target and then adjust the sights to be in line with the target? Will this save some ammo or time? Or should I just follow whats posted above?

Thanks.

I have never heard of anyone bore sighting an AR, but I'm sure it has been tried. I would recommend going through the normal steps in zeroing though. Yes, you will need to pay for ammo, but the point of aim and the center-line of the bore will be on two different planes for most of the time.

Hopefully this diagram will help out some. And I understand that this diagram is for 300M, but with an AR, you are also dealing with a mechanical offset that will cause your bore sight zero to be way off of your actual zero.

http://www.gunandgame.com/forums/attachments/powder-keg/20158d1238567400-very-technical-m4-vs-m16-question-trajectory.jpg

[woodwrkr]

Well sure, I'll be shooting some ammo and fine-tuneing the sights, but the bore-sighting is intended to get the rifle on paper initially in the same way as the method posted above. I suppose either method would work for initally getting the rifle on paper. I think I'll try the method above since I haven't used that one before.

Thanks for the help.

[Quib]

Well sure, I'll be shooting some ammo and fine-tuneing the sights, but the bore-sighting is intended to get the rifle on paper initially in the same way as the method posted above. I suppose either method would work for initally getting the rifle on paper. I think I'll try the method above since I haven't used that one before.

Thanks for the help.

I’ve heard of people using this method to get the rifle on paper, but have never tried it myself.

If I wanted to take this route, I would probably go with a laser bore sight over simply peering down the bore at a distant target. But to date, zeroing as outlined in the TM has yet to fail me.

ETA: If a person utilizes the zero target, following the front and rear sight diagrams to correctly adjust the POI towards the center of the target, I do not see that much of a difference in ammo used verses bore sighting beforehand. The only time I have seen excessive rounds used to zero a weapon, was when the shooter failed to follow the instructions on the zero target.

[Paulo_Santos]

Hi, first time posting here. I'm new to AR's but not new to shooting (I built my own 1911 from the ground up about 6 months ago). I'm going to be zeroing my first AR in a couple of weeks as soon as the barrel arrives. Can an AR be "bore sighted" in the same way as a bolt action rifle? In other words, separate the upper receiver from the lower with the BCG removed, set the upper on sand bags with the bore perfectly in line with the target and then adjust the sights to be in line with the target? Will this save some ammo or time? Or should I just follow whats posted above?

Thanks.

It can definitely be done and it works pretty well. But if you start at 25 yards you don't have to do it as a Battle Sight Zero will be very close. Even at 50 yards, a Battle Sight Zero is almost always on paper in my experience. (This is assuming you are using man sized targets.).

[Minimum8]

Another option is the "one shot zero". I have never heard of this being done with iron sights but works great with scoped rifles. The caveat to this is your fundamentals of marksmanship need to on the money. Set up at 100 yards (or whatever distance you are zeroing). Line up the reticle dead center over the target X and shoot one round (again, fundamentals need to be dead on or you will be chasing bullet holes all day). Next, have some way to brace the rifle in position with the reticle still on the center mark. Once that is done, adjust the reticle/crosshairs so it is dead center over the bullet hole. Your rifle is now zeroed. I usually shoot another round as a confirmation shot. Anyway, another option.

[zero7one]

Another option is the "one shot zero". I have never heard of this being done with iron sights but works great with scoped rifles. The caveat to this is your fundamentals of marksmanship need to on the money. Set up at 100 yards (or whatever distance you are zeroing). Line up the reticle dead center over the target X and shoot one round (again, fundamentals need to be dead on or you will be chasing bullet holes all day). Next, have some way to brace the rifle in position with the reticle still on the center mark. Once that is done, adjust the reticle/crosshairs so it is dead center over the bullet hole. Your rifle is now zeroed. I usually shoot another round as a confirmation shot. Anyway, another option.

I can see how that could be advantageous with a scoped rifle, but at 100 yards, iron sights would probably have too much room for error. Plus seeing a bullet hole at 100 yards with iron sights is nearly impossible, at least with my eyesight.

[hals1]

Hi, first time posting here. I'm new to AR's but not new to shooting (I built my own 1911 from the ground up about 6 months ago). I'm going to be zeroing my first AR in a couple of weeks as soon as the barrel arrives. Can an AR be "bore sighted" in the same way as a bolt action rifle? In other words, separate the upper receiver from the lower with the BCG removed, set the upper on sand bags with the bore perfectly in line with the target and then adjust the sights to be in line with the target? Will this save some ammo or time? Or should I just follow whats posted above?

Thanks.

I did that with a 16" Bushmaster and a 20" BCM with scopes and it got me on the paper at 35 yards within about 3-4 inches. Bore sight target was about 75 yards away. YMMV

[sonny22]

If I did the 25 yard zero would I use the large or small aperture?

[Paulo_Santos]

If I did the 25 yard zero would I use the large or small aperture?

Small aperature.

[TehLlama]

Boresighting can be an aid, but the above certainly works, and any boresighting would still need to be verified by going and shooting it - always going to be a difference between lining up a laser, and where your precise POA is when breaking a shot.

[AR-10]

This is a good thread.

Here is a page I had bookmarked, zero7one's diagram is better but this is a good read:

http://www.recguns.com/Ballistic/ballisticsBackground.html

[rob_s]

I have boresighted *almost* every AR I've zeroed over the last several years, and I've used the method where one looks down the barrel. I do this to get on paper and nothing else, and it works quite well and saves a bit of ammo/time at the range.

RE: the BZO, I didn't realize anyone was still doing/teaching that outside the military. If you're going to use iron sights simply use the small aperture to get 1.5" low at 25 yards, dead on at 50, and get yourself a hard zero at 200. If you boresight to 50 before you start you'll save yourself a little bit of time and ammo. One of the benefits of attending a Randy Cain Carbine 1 course (as I just did, with irons, this past M-W) is that you walk away with a good, hard, confirmed 200 yard zero on your gun, following this method.

If you prefer a 100 yard zero (I do) then get 1.5" low at 25 and then move straight out to 100 and get dead nuts. Shoot at least a 5 round group, I prefer 6-10. Even if your groups aren't so small they can be covered by a nickle you can still plot the center of the group if you have enough holes to do it. 3 holes is not enough.

I like to swap out to a same-plane sight aperture but it's not necessary.

IMHO there are some places that the manuals haven't caught up, and zeroing is one of them, regardless of whether you're using iron sights or optics. Learn the benefits of 100 and 200 yard zeros and make your choice based off of what you learn.

[sonny22]

If I was just using iron sights and used the small aperture to zero at 25 yards how much off would I be when I switched to the large aperture?

If I was just using my carbine for home defense and shooting 0 to 150 yards would it be better to use the large aperture?

thanks for the help and sorry for all the newbie questions.sonny

[Paulo_Santos]

If I was just using iron sights and used the small aperture to zero at 25 yards how much off would I be when I switched to the large aperture?

If I was just using my carbine for home defense and shooting 0 to 150 yards would it be better to use the large aperture?

thanks for the help and sorry for all the newbie questions.sonny

The Large Aperature is mainly used for low-light shooting. Most people have a hard time hitting the target past 50 yard with the large aperature because you have to perfectly align the front and rear sights, which is hard to do with the Large Aperature. I have no idea what the POI will be when you switch to the large aperature because I only use the same plane aperature and even when I had the A2 Aperatures, I never used the Large Aperature. In theory, at CQB distances, you should be shooting closer to where you aim instead on the 2"-2.6" holdover that you have with the Small Aperature.

[rob_s]

First I would say that you need to get away from this "zero at 25 yards" business. Regardless of whether you go point-of-aim equal to point-of-impact or 1.2" low, or 1.5" low, or whatever, 25 yards is all wrong. If you POA/POI you'll be launching rounds into the stratosphere downrange (not really, but you will be ridiculously high), and even if you get a POI below POA you'll still need to reconfirm at your intended range.

As mentioned, I just got done taking a class where I shot all irons. I used the small aperture in my Troy fixed rear sight for all but the very close range (under 25 yards) and the low-light portion of the class. Even at distance at night (we shot at about 75 yards in the dark) I found the small aperture worked better for me.

Finally, get out and shoot. This is too rarely made clear. Pick something, get it dialed in, and then go out and use the thing to test your choice(s).

[Paulo_Santos]

I forgot to mention before about the zero range. I'm a firm believer in the 100 yard zero. It is the easiest to learn because everything is holdovers. No holdunders like the 50/200. And realistically, most people don't shoot past 100 yards on a regular basis, especially with irons.

[AR-10]

I am interested in the 100 yard zero mentioned above, especially since my local rifle ranges are all 100 yards.

How do I do this with a fixed front sight, and a Troy rear with no elevation adjustments?

Is this a good zero for a carbine course?

[rob_s]

On the AR system you adjust elevation on the front sight, and windage with the rear sight. I just spent a 3-day class with a fixed front sight base and a Troy fixed rear sight. If you look at the sights they are marked with arrows and notations (for example, the front sight says "up" with an arrow). Turning the sight in the noted direction moves the bullet impacts in that direction (so turning with "up" moves the bullet holes up). You can use the tip of an FMJ round to press the detent and turn the sight both in the front and the rear.

Whether or not it's good for a carbine class is going to depend on a lot of other factors, not the least of which is the instructor and whether the class is really "pistol shooting with a long-gun" or "rifle shooting with a carbine". If it's the latter chances are good that you will be re-zeroing at the class anyway.

[AR-10]

That part I get - but after reading Molon's version of the IBZ it looks like the improvised battle zeros are meant for carry handles and A2 uppers with elevation drums?

I've got a tool to adjust the elevation on the front sight, I was more concerned with the Troy rear...

[rob_s]

That's one of the problems with this antiquated IBZO business, it confuses people for no reason on equipment that nobody is using anymore.

Zero the gun at 100 yards. Set up and shoot a group about 1.5" low at 25 yards and then move out to 100 and get Point-of-Aim=Point-of-Impact. Adjust the front sight to move POI up/down and the rear sight to move POI left/right. Focus on one axis at a time, don't try to do both at once. Get the group centered at 25 horizontally, then move it up/down to get it 1.5" low. At 100 you should only need to adjust for elevation, but you may still need slight adjustment in windage. IIRC the Troy sight should move the POI 1/2" at 100 yards for each click.

[AR-10]

Thank you.

That is exactly what I wanted to know.