If I sight this rifle in at 25 yards to POA with 5.56 NATO 62 Grain Bullet:
Where will the bullet print at 100 yards ? (high or low from POA)

It will shoot very high at 100.

~5" (with std height sights), but ultimately dependent on barrel length (velocity) and sight axis over the bore.

Many ways to sight in but always verify at the range you want to be most precise at. Tons of videos out there.

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Hue 68 noli me tangere

I use a ballistic calculator to sight in my ARs and I have found them to be very reliable.

If you want a 0.0" impact at 100 yards you should be a -0.7" at 25 yards.

If you sight it in at 25 yards you will be 3.0" low at 100 yards

You must bear in mind that velocity (barrel length) will affect that as well as what sights you have (A1 or A2, etc.)

I was kind of in a hurry with my first post and didn't have time to dig. I'm still having trouble finding a 62g chart, but this should give you an idea of what you're looking at:



This information coincides with my experience with 55g bullets, but a 62g shouldn't be substantially different under 200 yards.

AR zero is a topic right up there with best gun cleaning oil, best caliber and Glock v. 1911...

I personally like a 50/200 yard zero for a practical carbine... essentially zero holdover for muzzle to 200 yards.

Jimmy, we're missing information on exactly which rear sight-or even if you're using iron sights-you have and it makes a difference (just the L sight or the later A2 version) in the mechanics*. However, post 6 gives you a road map.

About 1 inch low and centered horizontally at 25 yards will get you on paper at 50 yards. POA/POI at 50 yards will keep you within +/- 2.5 inches of POA out to over 200 yards. You'll need to shoot at longer range to confirm as small errors you don't see at 50 yards will show up at longer range.

There's not really enough difference between 55 gr and 62 gr to worry about. FWIW, out of a 16 inch barrel, with an Aimpoint Pro sighted in as above with 55 gr ball, the Hornady 75 gr HPBT stays inside the 2 MOA red dot (about at the top of the dot at 100) out to 200 yards. We didn't have the range to go beyond that. Even if you're using optics, sight the irons in.

*Reading Colt's instructions for the A2 sight system made me really appreciate all the things our armorers did for us.

Actually with the stock iron sights , the velocity loss with 16in vs 20in closely matches the effect of the shorter sight radius .

How to you intend to use it , and how do you Want it sighted ?

The default millitary doctrine for open field combat is formulated around aiming at the belly of the enemy , and hitting them somewhere on the body to maximum distance . The trade off is high trajectory at 100- 2 00 yds .

For many civillians , and some units primarily in closer urban environments b the 50 yd initial zero keeps impact within +/- 2 in to beyond 200 yds .

Unless you are only ever going to shoot on a fixed 100 yd range , a 100 yd zero is not very useful , and you're giving up a lot of the versatility of the rifle/ cartridge .

At least for defensive purposes, sighting an AR in at 100 yards is recommended, as you will pretty well be assured of hitting somewhere in the C-O-M area of a human sized target with a C-O-M POA, fired from any range of 0 to 200 yards.

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SIC SEMPER TYRANNIS

If you are using GI iron sights, your sight height (H) above CL bore is 2.625".
If your are using 55gr .223 or M193 5.56 ammo, your muzzle velocity (MV) from a 16" barrel will be in the 2,800 to 3,150 fps range, and the bullet is probably a 22 Cal. .224" FMJ-BT w/c with cannelure with a ballistic coefficient of .243
H - sight height above bore
MV - Muzzle Velocity
Point of Impact (POI)
Point Of Aim (POA)
For sight height 2.625" GI iron or co-witness optics at 25 yards:
At MV 2,800 fps, POI is 1.5" below POA for 100 yard zero.
At MV 2,900 fps, POI is 1.5" below POA for 100 yard zero
At MV 3,000 fps, POI is 1.6" below POA for 100 yard zero
At MV 3,150 fps, POI is 1.6" below POA for 100 yard zero.

This should get you pretty darn close to hitting anything deer size at 100 yards.
If you dig and get some MV info on your ammo and go to Hornady and get a ballistic coefficient for the bullet, you can use their calculator to play with all these variables and look into a longer zero, or change the sight height if yours is different. I suggest using 25 yard intervals out to max 400 yards and play with different zeroes to see where you might find an optimum for your application.

I prefer a 250 yard zero for my rifle to hit a silhouette easily anywhere 0-300 yards with very little under or over hold. For bullseye shooting , YMMV.
Have fun - next thing you know, you'll be addicted and buying chronographs and reloading equipment.

Ballistic Calculators - Hornady Manufacturing, Inc

This will answer your question;
http://www.arma-dynamics.com/red-dot-zero-targets.html

Re: post #s 6, 7 & 8... Well, then 50 yards it is! Thanks, guys!

Cheers!

P.S. Can't really imagine shooting at anything over 200 yards away (unless they were shooting at me 1st!) with a 223/5.56...

It will depend on the BC of the bullet from ... .274 to .298 etc and
the FPS of the ammo that cane be from 2817 to w-w at 3100 fps etc.

The BC .274 at 2817fps at 1.5" avove bore sight can be around.....
25 yd Zerro.......... 50yd 1.2.............. 100yd +2.6....... 200yd +1.1"

The BC .298 at 3100fps out at 200 yards can be around.......... +2.8"

this is with my info data finder , systems will vary.

Just learn about BC and fps if you need to go past 250 yards.

With M855 sight in @ 50yds then aim center mass from 0 to 300 yds and your POI wont vary more than about 9".
For an AR with a 14.5" to18" barrel the 50-200 zero is I think the most useful zero. If you do use this zero you should be about 1.5" high at 100.

Literally just got home from a 2 day instructor class for LPVO (low power variable optics) on ARs.

We were using a 50yd zero and shooting from CQB to 300 yards. No problem making hits, and no compensation needed for anything but CQB, and a bit of hold over at 300.

Definitely the most versatile real world zero.

Details matter and I’m not sure a few of them have been covered.

Sight height matters and the OP didn’t mention whether he has The standard carry handle sights or something else.

The carry handle sights are centered 2.6” above the bore, so the bullet has to rise 2.6” before it reaches the line of sight. With a 25 yard zero that’s a very steep angle of departure. With M855 at 3025 FPS muzzle velocity that leaves the bullet with a maximum mid range trajectory about 11” high at 225 yard with a 400 yard zero.

With a 50 yard zero the angle of departure is reduced by half and the mid range trajectory is 2” high at about 135 yards. The resulting return to the line of sight will be a 225 yard zero. It will be about a foot low at 350 yards and about a foot and a half low at 400 yards.

That’s a much more practical zero and it will be about 1.2” low at 25 yards if you want to do an initial zero at a shorter range.

For a standard A1 or A2 style AR-15 with carry handle sights, a 50 yard / 225 yard zero will be about 1.6” high at 100 yards and you can effectively aim dead on a torso sized target out to about 300 yards. Since you are about a foot low at 350, you can hold level with the top of the shoulders and a 400 yards hold on the top of the head (which at 400 yards is the top of the visible torso target as the head won’t be all that distinct).

——

If however you have an AR-15 with a Picatinney rail and a low mounted reflex sight, with a line of sight maybe 1.5” above the bore it changes things.

In this case a 50 yard zero is only -.6” low at 25 yards with a maximum mid range trajectory of just .5” at 100 yards with a return to the line of sight at about 135 yards. It’ll be about 6” low at 250 yards, a foot low at 300 yards, a foot and a half low at 350 yards and 2 ft low at 400 yards.

In comparison a 25 yard zero will result in a maximum mid range trajectory of 3.5” at 150 yards and a return to the line of sight at 250 yards. It’ll then be 3” high at 100 yards for longer range zero confirmation purposes. Downrange it will be 3.5” low at 300, 9” low at 350 and a foot and a half low at 400. That makes a 25 yard a much more practical zero for torso sized targets out to the AR-15s real world effective range of about 400 yards.

——

So…a 1.1” difference in sight height makes a lot of difference.

With the higher 2.6” sight height a 50 yard zero makes the most sense.

With a low mounted sight, 25 yards will probably be a much better choice.

25 yd zero for my 16 ich bbl Sport was 5to 6" high at 100yds

How much do you want to know?

TC 3-22.9 Rifle and Carbine

One of the first big changes I found in my rifle shooting was while transitioning from the M14 7.62mm to the M16 5.56mm. The sights of the M16 are way higher above the axis of the bore.

The Army had a target we used to zero our M16 rifles. The target had an aiming point and an area indicated for impact point at 25 yards, which was a couple of inches below the aiming point.

The original M16 rifle had a rear sight with two apertures, one for 0 - 250 meters, and the other for 250 - 360 meters (maximum effective range, according to the "book" at that time).

As others have noted, military applications rely primarily on the goal of striking within the torso area of a man-sized silhouette target. Whether the bullet strikes 2 or 3 inches high or low at any given range is not a major consideration, the only objective is to strike the target within the torso area. So, from that perspective the entire discussion of "zero" for the rifle is not in the military lexicon.

Much different for the varmint hunter seeking little critters at variable ranges. Much different for the game hunter chasing 200 - 800 lb. critters at any range.

Most of my rifles have metallic sights, a few have telescopic sights. All are different (type, caliber, trajectories, etc). Most are capable of very fine accuracy, but a couple can only do "minute of pie plate". No general rule applies to all of them.

I sighted my carbine (16 inch barrel) AR at 50 yards. Just seemed to be the best practical distance for a civilian AR for defensive use.

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VCDL, GOA, NRA

Pat Rogers had us using the 50/200 (which if IIRC is about 215) because from 25 to 250 or so it is a combat useful POA/POI overlap based on typically 5.56 trajectory. The offset for inside 25 yards was more or less compensated for by aiming at the hairline to hit in the eye socket. If you aim for the nose, POI tends to be about the lower jaw, which is sub-optimal, but aiming at the chin is likely to hit the throat. The neck is full of vitals.

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NHI, 10-8.