I've never sighted in my AR.  I might try to do that this week.

Any tips?  25 yards?  Do I need a spotting scope (I don't have one)?

For now, just iron sights on this rifle.

I like to use the "Shoot N C" targets that visibly show you where you hit. I always use a spotting scope or you can use binoculars. I like to use a 50yd zero on BUIS. IIRC it puts you within a couple inches out to 250yds.

Biggest thing to remember is the concept of "FORS"....

Front sight should be moved in the opposite direction and the rear sight should be moved in the same direction as your intended point of impact.

Example, if your hits are high and to the left, you want to the front sight up and rear sight to the right.

Not necessarily efficient but start off around 10 to 25 yards away from target, fire three to five shots, than correct impact for left to right.  Keep repeating till the grouping is somewhere on the center line.  Move back to 50 yards or so and repeat firing groups of 3 to 5 shots and correcting for left and right.  Keep repeating that moving back, firing groups, and correcting for left and right till you are at the distance you want to zero the sights in for then start correcting for elevation after correcting for left and right.  I prefer using 3 shot groups till I get close to where I want the grouping to be at some distance, then use 5 shot groups for fine tuning, then fire 20 to 30 shots to confirm the zero.

Could correct for both at the same time but assuming the gun isnt hitting the very top or bottom of the target I always found correcting for one variable at the time is best.

Also zero in the gun with the ammo you are expecting to use out of the gun for it's intended purpose.  Different bullet design, weights, gun powder loads, and countless other variables will all change point of impact.  Ammunition using the same bullet weight and bullet design but from two different brands will almost certainly have different point of impact which will get increasingly noticeable as range increases.

Spotting scope helps if you dont want to constantly be walking back and forth from where ever you are shooting and where the target is.  Those high visibility impact targets are also a bit helpful in that regard too.  One thing that will help is having some kind of shooting rest to use, even if it's just sand bags.  Anything to remove shooter error while zeroing in a rifle will help massively.

Do you know what sights you have? X-brand folding front and rear, triangle/barrel mounted front, carry handle rear, etc?

For now I'll suggest using a 6-10 MOA diameter black circle on a big, light background like the SR-1 (not SR-1C). This Shoot-N-C should fit right over the SR-1 black.

Spotting scopes are nice to have to save on waiting thru Hot line time and walking. I suggest Konus as a minimum.

The 15 Yard offset/50 Yard printable target makes it really fast. Dial it up at 15, verify and adjust if needed at 50/200.

Thanks all.  

I was able to sight two ARs in on Monday evening.  I brought a scope from my 10/22 as a spotting scope, but couldn't see crap with that, so a LOT of 3 shots, walk to the target, make adjustment, 3 shots, walk to target.  

Luckily, I had the range to myself, so it wasn't too bad.

What is bad, however, is my damn eyesight.  So hard to focus on that front sight.  I guess a red dot is in my future.

Rifle or mid-length gas block sights are easier to focus on than carbine length and the longer the sight radius the easier it is to pick up mis-alignment. Put your eye as close as possible to the fine peep reduces rear sight induced parallax as much as possible.  For a practical iron sight zero a 6 o:clock hold on a black target at 50 yards with a 5-shot group centered at the bottom edge of the black generally is a good enough zero for iron sights.  You can follow up on a calm day at 100 and 200 for windage sight adjustment refinement with 5 to 10 shot groups. A tall target helps at 200 to see where your elevation far crossing sits relative to 50 yard zeroing.  Once that’s done grouping with different ammo will tell you if further sighting work or an optic or better trigger will pay off.  Red dots are almost always an improvement with both eyes open and better target contrast but parallax issues still requires good cheek weld.  Have fun.

I use a laser bore sighter for preliminary adjustment.
My AR10 sight height is such that if I sight in at 50 yards, it will zero at 200, and be a hair over an inch high at 100, with my sight height, and 150-ish grain ammo.
My neighbor's front door across the street from me is 47 yards from mine, so I set up my upper, 9 feet back from my front door, and shine the laser on it in the wee hours of the morning, and dial in both iron, and optic sights.
Always within a couple inches or less when I get to the range, and saves on ammo.
My laser is one of the El-chinco $10 ones off eBay.
It has mandrels for .17 caliber up to 12 gauge, and also makes a fun cat toy

the parameters for zeroing your iron sights depends on barrel length, ammo, detachable handle or not, and whether they are A1/A2/A4/M4 sights.

go here http://nuke.42web.io/ar15w.html and go to section 4.1.7 for zeroing. if you're up to it you can read the whole section 4.1 and learn everything there is to know about iron sights.

20" barrel --------------------------------

if you have an A1 and you are shooting M193, zero the rifle at 25 meters with the small aperature. the near zero is at 25 meters, far zero is at 375 meters. THEN when you flip to the large aperature the near zero is 43 meters, far zero is at 250 meters.

if you have an A2 with fixed carry handle,

a) put the elevation drum on 8/3. if you are shooting
M855, set your target at 30 meters
M193, set your target at 31 meters

b) put the elevation drum 1 click up from 8/3. if you are shooting
M855, set your target at 25 meters.
M193, set your target at 27 meters.

if you have an A4 with detachable carry handle,

a) put the elevation drum on 6/3. if you are shooting
M855, set your target at 30 meters
M193, set your target at 31 meters

b) put the elevation drum 2 clicks up from 6/3, or use the Z mark. if you are shooting
M855, set your target at 25 meters.
M193, set your target at 27 meters.

to be more accurate, use 30.63 and 31.55 instead of 30 and 31 meters.

THEN for either of those,

zero with the small aperature. if you are shooting
M855, the near zero is 30 meters, far zero is 300 meters
M193, the near zero is 31 meters, far zero is 300 meters

when you flip to the large rear aperature, if you are shooting
M855, the near zero is 47 meters, far zero is 200 meters
M193, same as M855

16" barrel --------------------------------------

if you have a 16" commercial rifle with a
fixed carry handle, put the elevation drum 1 click up from 8/3
detachable carry handle, put the elevation drum 2 clicks up from 6/3

if you are shooting
M855, set your target at 25 meters
M193, set your target at 27 meters

THEN for either of those,

zero with the small aperature. if you are shooting
M855, the near zero is 25 meters, far zero is 300 meters
M193, the near zero is 27 meters, far zero is 300 meters

when you flip to the large rear aperature, if you are shooting
M855, the near zero is 44 meters, far zero is 200 meters
M193, same as M855

14.5" M4 barrel --------------------------------------

if you have an 14.5" M4 with a
fixed carry handle, put the elevation drum on 8/3
detachable carry handle, put the elevation drum on 6/3

if you are shooting
M855, set your target at 25 meters
M193, set your target at 27 meters

THEN for either of those,

if you are shooting
M855, the near zero is 25 meters, the far zero is 300 meters

when you flip to the large rear aperature, if you are shooting
M855, the near zero is 42 meters, the far zero is 200 meters

grouping -----------------------------------

army: fire 3 shots. group must be within 4 cm otherwise no good and try again.

civilian: fire 5 shot groups.

then adjust as needed.

The biggest mistake I see people making is attempting to zero without firing a group.

DO NOT fire a shot or two and adjust, then fire again and adjust again.  You are just chasing holes in the paper.

DO fire a group of 3-5 shots holding a consistent point of aim.  Then adjust sighs to move relative center of that group in direction desired.

Older video but it should help folks reading this thread in the future.

For quick reference.
Just incase you need for future use and didn’t already know this.

Anytime I change out an optic or irons. I always do a mechanical zero first, it will get you on paper. I then zero on a 25y range.

To get a mechanical zero:
Center front sight post flush with A2 base. Rear sight, Rotate windage knob left all the way. Then, count clicks going allllll the way back to the right.
Divide that number you got by 2. And now click back to the left with the divided number centering the Windage knob.

I’ve had good succcess with doing this that always gets me on paper. From 10.3”-16” barrel out to 50 yards a couple times. But mostly 25y. 62g 5.56 freedom munitions mostly.

Typically 2-3” off bullseye after mechanical zero. Hope this helps  

I use 25 yds. for a start and many others have stated good reasons for this distance. Use search terms like- sighting rifle scope. Have fun!

https://www.nrafamily.org/content/5-easy-steps-to-zero-your-ar-15

I am surprised that out of all the responses, only one responder mentioned starting with the sights at mechanical zero. Start there FIRST, before doing ANY thing else.
Jon

Good point.  That works well for uppers with good aligned pinned front sight bases and/or solidly concentric barrel/handguard torque-ups. Otherwise lots of mismatched or cheap parts will eat much of the rear sight windage on final zero.  Elevation is usually less of an issue.  

I’m always amazed how well mechanical zeroes work on a Glock slide, but how many cheap AR uppers suffer from huge offsets from mechanical zero.

Post some pics of your groups fired at 100 yards from your Glock with a mechanical zero.

...

Touche’.  I expect about 16-20 MOA from a lightly rested hold with typical bulk 9mm ammo in a Glock. With a mechanical zero I’d be amazed if windage was on a silhouette at all at 100 yds.  Hold over at 100 I have no idea. I usually take a 6 o:clock hold on the head and then slowly raise the front sight above the notch.  Hit probability is low with aging eyes and iron sights.

But given how sloppy a Glock barrel sits in its slide, I am always surprised that a mechanical zero gets close at say 15 yards and in. Close enough to get on paper to begin adjustments.

Many of the cheap AR uppers I’ve helped people zero have grossly misaligned front sights.

Google dennistalksguns. Scroll down to the one that says how to sight in a carry handle rear sight for competition. It is an excellent tutorial (as are all of his tutorials and I know him personally and he won't steer you wrong). He explains it in simple language and good clear video. I tried it and it works--spot on. Give him a look-see. You have nothing to lose and every thing to gain.
Jon

I get on paper at 10 yards and then move out to 50 yards and sight in for 1" low at 50 yards

My sight-in on a new rifle is much like others here.

I start at the 25-yard range and sight the rifle to shoot 3 inches low. This is to mainly just get on target with the fewest shots.

Then I move to the 50-yard range and sight in for the final zero.

This should equate to approximately 3 inches high at 100-yards, and back on zero at 200-yards.

It is really a simple process.

Just my opinion, but it’s only an easy process once you get on paper. However, getting on paper can be a frustrating experience!

If my first round at 25-yards is not at least on the paper, I will walk up to about 10-yards from the target and fire a round. That is rare, but has always worked well enough for me to be on the paper.

All the best!

setting the sights to a mechanical zero initially, helps

Focus on the front sight, NOT the target. Focus on the FRONT sight and don't switch your focus from the FRONT sight to the target and back. Keep your FOCUS on the FRONT sight--the rear aperture and target will be fuzzy but the FRONT SIGHT will be in FOCUS.  Are you seeing a pattern here. Just in case you don't see it, FOCUS ON THE FRONT SIGHT.
You're welcome.

Make sure you have a solid setup like sandbags to rest your rifle on. I personally love the 50 yard zero as it stays within a couple inches out to 250 yards. Put your first shots on target at closer range such as 15 yards and work your way back. Also make sure you have the proper tools to allow you to move your sight to move up/down for elevation and left/right.

This works... I'm not sure of the need to start at a closer range than 50 yards though. I just went through the process of sighting in the iron sights on 4 ARs over the last few days and was on paper from the start with all 4 of them. One of them (a factory assembled Colt 6720 upper) was way off for windage and still somehow managed to stay on paper for the first shots... I'm kinda surprised at the Colt because they're usually dead centered for FSB alignment. I knew it would be off though because I had checked it with my alignment gauge (and it was a bit off) a couple of months prior to this weeks range session.

thanks , my last one died and i had forgot about them. off to e bay

I've had some that weren't on paper at 50yds and I had a bitch of a time figuring out how to get them on paper.  For those frustrating moments, coming in to 27yds can help.

I've had setups dial right in with minimal adjustments, but others frustrate me. LOL

You've had them that far off with irons? I could see it happening with a scope that was previously zeroed on another rifle, or with BUIS with the front sight mounted at the front of a railed handguard.

Bigger. Paper.