Iron-sight accuracy for AR-15 at 100yds

[lexnaturalis]

What's a good grouping for iron sights at 100 yards when using iron sights? Assume a sitting position where you can support your arms (with a table, sand bags, whatever).

I'm using standard A2 front sights and flip-up rear sights (just a small circle). I'm not sure what adequate grouping is, so I'm not sure if I'm shooting well or if I suck.

For now I'm using a mix of various factory ammunition. Barrel is 16" 1x9 twist.

All of my shots are on target, but I generally can't get much better grouping than a 6" circle (that is, all shots are +/- 3" from the center of the target).

Is that decent? Terrible? Excellent?

[Pukindog]

I shoot a Colt H-Bar in CMP competion. I do have a Bob Jones rear sight aperature on the rifle which really helps. I am 68 Y.O. and have "old eyes"
I have an average of 464 out of 500 for the season. My groups are usually within 3" of measurement. Sometimes there may be an 8 ring flyer which will open the group; sometimes I shoot a smaller group. Depends upon many factors; light, wind, temperature, how much coffee I drank, backache, etc.
Off a rest I can hold 1 1/2". I shoot handloads with match bullets.

Jeff

[JMIS]

What's a good grouping for iron sights at 100 yards when using iron sights? Assume a sitting position where you can support your arms (with a table, sand bags, whatever).

I'm using standard A2 front sights and flip-up rear sights (just a small circle). I'm not sure what adequate grouping is, so I'm not sure if I'm shooting well or if I suck.

For now I'm using a mix of various factory ammunition. Barrel is 16" 1x9 twist.

All of my shots are on target, but I generally can't get much better grouping than a 6" circle (that is, all shots are +/- 3" from the center of the target).

Is that decent? Terrible? Excellent?

I would think your doing pretty good with a 6in group at 100 yds open sights.

[tdyoung58]

How much do you shoot it? How many rounds have you put downrange?

There are a lot of variables with a AR, trigger and how everything fits together can mean a lot

Try using a smaller target as well, I usually only use a 3" dot on the back of a regular target.

[chauncey]

i shoot a Colt HBAR with 20" barrel. it's not a rifle i shoot a lot, but i have achieved 1" groups at 100 yards with iron sights shooting standard XM193. typically my groups are more like 2"

here's some tricks you should try:
1. 4" dot for visibility on a white background. shoot-n-see's are a good choice. the smaller the target you can see, the better your groups. but the target has to big enough for you to see
2. adjust your point of impact for a 6" hold, so you "dot the i" with the front sight post. this really isn't "proper" sight picture for peep sights but if it works for you, who cares. it will through off your dope a little bit if you transfer to longer range shooting
3. beer can grip on the bench. never knew there was a name for it until a few weeks ago!
4. snap in, at home. prctice all the way through dry fire. i draw tiny little B-27's on post-it-notes and stick them up at the end of the hallway
5. get at least decent quality ammunition. i personally have a lot of success with XM193. not so much with PRVI
6. the 16" M4-style barrel isn't doing you any favors
7. NM sights. the smaller the front sight post and the smaller the rear aperture (to a point) the more accurate your shooting. this is a pretty inexpensive upgrade
8. LASIK or at least contacts remove the error introduced by corrective lenses, due to distortion at the edges of the lense and the distance between your eye and the corrective lense, being eliminated

other than the ammunition selection, none of these ideas are AR-specific

[lexnaturalis]

How much do you shoot it? How many rounds have you put downrange?

I've probably taken it to the range 5-6 times, and I've put a total of ~200 rounds through it so far. It's my first AR-build.

[lexnaturalis]

7. NM sights. the smaller the front sight post and the smaller the rear aperture (to a point) the more accurate your shooting. this is a pretty inexpensive upgrade

I've looked at some new sight posts, but I wasn't sure if they made that much of a difference. For the price, though, I suppose it's worth a shot.

8. LASIK or at least contacts remove the error introduced by corrective lenses, due to distortion at the edges of the lense and the distance between your eye and the corrective lense, being eliminated

I have 20/20 vision, so that probably won't help me much

[A_Wrench]

Are you familliar with MOA "Minutes Of Angle"? 1 Minute Of Angle is roughly equivalent to 1" at 100 yds.

The upper torso of a 6' man at 500 yds is 4 MOA wide.

The standard front iron sight post on AR's is 6 MOA at 500 yds.

So if your keeping a 6 MOA group with random ammo... Your doing pretty good at keeping the "Redcoats" at bay.

[Pete D.]

I shot my best group ever - I rarely shoot for group - during load development when I was playing with my HBar a few years ago.
It was a half inch group of five shots at 100 yards using NM sights. Benched. The bullet was a 52 grain match bullet - Hornady, IIRC. I'd have to look up the powder charge but the propellant was RL-15.
Pete