ammo waste-a-rama sighting in AR yesterday.

C

colostomyclown

New member
So, having not shot groups with a rifle in 2-3 years and another 3-4 years before that, I decided to take my new AR out and "zero" it in. Well, long story short I wasted about 110 rds of brass cased ammo, in grains I don't intend to shoot, now having a gun and optic sighted in at a funky range I'm unsure of. To top it off, my accuracy was laughable. When I'd retrieve the targets I'd immediately make a beeline to the range trash to hide the evidence. :(

So, this thread has a dual purpose. First, I have some questions. Second, to remind everyone to PRACTICE. And certainly not to attempt benchrest sighting methods after such a long layoff. Maybe some can, I thought I could, but I just burned through a bunch of ammo for no reason before I knew it. Fun? yes. Do I feel guilty, though? Yes. The upside - I left feeling like I can go back next week and if I take my time and regroup, I can have my rifle working more like a laser than a market hunter's blunderbuss.

Questions - What is your personalco-witness zero method? I forgot the front sight adjustment tool, realized my fat fingers couldn't do without it and jumped straight to the optic setting the day off on a bad note. Attempting to zero just the windage on the irons after I wrestled with the optic vs. my poor shooting for 80 rounds. :rolleyes: This time, I'm removing the optic, bringing the front sight tool, and making the sure the BUIS are dead on before even mounting the red dot. Then getting the optic dialed in and HOPING that dot is on top of that post.

Anyone experience this after a long layoff?
 
I've never had that long a lay-off, but I've had trouble co-witnessing sights. I was using a cheap red dot and, like you, I could never get the red dot to sit on top of the sight post and still hit the target.

My first answer was to zero the weapon with the irons, then mount the red dot and zero the weapon with the red dot. The rifle would shoot fine if I was looking at the red dot, and the rifle would shoot fine if I dismounted the optic and used the iron sights alone. I never could get the two to co-witness. Probably a parallax problem of some sort.

My final solution was to dismount the optic and give it to the grandkids to play with. Nowadays my AR doesn't have any optics and is an iron-sight-only rifle.
 
Try shooting your target at a closer range if you're having problems at a 100 yards move your target to 25-50 yards,also make sure you have a solid rest.
 
I am not using an aimpoint so it's not terribly expensive, but it is a Vortex Sparc which is apparently pretty highly thought of considering the price point and performance. Yesterday it did great and I attribute none of the issues whatsoever to the optic. I knew when I shot bad...just so rusty it's hard to get out of the rut and settle down. However, I have a feeling when I have everything dialed in at 50 yards for an IBZ and I'm shooting with both eyes open, that dot wont be on that post. Parallax? maybe....
 
Also, I was using 3-shot groups which probably wasn't the best idea. Is 5 shots always better than 3? I will probably move over to 5 next week.
 
My "ZERO" is always done with 3 shot groups. Fine tune at longer (more than 250 yrds) with 5 shot groups. As for Co-witnessing..... I don't try to make an Orange taste like an Apple. Either Iron or Optic. Always said you can get them close if you stay close. This to me is the reason for flip up sights. If the red dot fails, turn it off and flip up the irons. But I use laser etched cross hairs. They don't require batteries, and I do not keep both on one rifle anymore. Not trying to bash, just think you should work on one thing at a time especially after so much time on the side lines. Best of luck to ya.
 
I have not done what you are trying to do.I will speculate.
The issue may be sight height.The red dot sight height would have to be precisely identical to the sight height of the tip of you front sight to acheive what you are looking for.
I have a 1.5-5 VX3 mounted on a rifle.At low powers,you can see the front sight in the field of view in the scope.It is way low of the target because the scope is taller.
Long ago some iron sight rifles would have a barrel mounted open sight and a tang peep.There are problems looking through a peep and an open rear sight at the same time.The answer was the Beech Combination front sight.This was really two front sights,at different heights.The hooded bead was taller,to place it above the line of sight of the open rear sight.This is what was used with the tang peep.
 
Questions - What is your personal co-witness zero method?
Click to expand...

Any co-witness technique I use is used solely to get me "close enough" on paper to make final adjustments with live fire.

The first thing I do is zero the irons. I use a boresight laser to get me close, than tweak as needed with live fire.

I always start my live fire zero at 25M and simply confirm at range, tweaking as / if needed. Usually, I don't need to touch them after that initial zero though, as I'm going for man sized targets and not an x ring.

I'll use the irons to co-witness the optic, however, if the optic doesn't have a see through mount, I'll use the barrel. Simply remove the lower receiver, pull out the bolt carrier, and mount the upper on a steady platform. Pick out a far target, orient the upper so you can see your target through the bore and secure in place. Adjust your optic onto the target, confirm by comparing the "sight picture" through the bore and optic. Finalize with live fire.

HOPING that dot is on top of that post.
Click to expand...

I wouldn't worry about that. Co-witness to get close, confirm with live fire. The dot will be where it needs to be, and that may not be on top of the front sight post.
 
Just get them both zeroed. Of they co-witness, great. If not, who cares? The irons are zeroed, the optic is zeroed, the next step is practice, practice, practice. This guy's recommendations are zero both at 25 yards, using five-round groups. The intended recommendation is to be minute-of-man accurate, not blowing out the 'X' on a bulls-eye. If the optic itself is crap (it will take quite a bit of shooting to figure that out, if it is indeed a problem), then at least you have a zeroed irons. If that's all you have...once again, practice, practice, practice.

One thing that has worked for me is to be as consistent with the ammo as possible. Different grain ammo has different ballistics, so zeroing your optic with 55-grain ammo then using 75-grain ammo as your normal round might produce some discrepancies in accuracy and grouping. Best of luck and have fun at the range!
 
I have not done what you are trying to do.I will speculate.
The issue may be sight height.The red dot sight height would have to be precisely identical to the sight height of the tip of you front sight to acheive what you are looking for.
Click to expand...
Not so. Red dot sights are supposed to be parallax free. So even if you're looking through the sight a little high or low, the dot should remain on the target. That's the whole idea of a lower 1/3 cowitness.

cowit1-1.jpg
 
This 25-yard battle zero is recommended often, and I still disagree with it.

In the past 10 days I tested four ARs with four different sighting systems, three different sighting planes, two different barrel lengths, four different barrel configurations, two different twist rates, two standard Colt factory handguards, one drop-in after-market aluminum handguard, and one free-floated barrel with custom handguard.
No match barrels, nothing fancy, all four were original factory barrels that came on the guns.

50, 55, 68, 77-grain bullet weights.
Zeroed all four initially at 25 yards with the 55-grainer (traditional & common bullet weight).

Fired all four guns with all four loads at 50, 100, and 200 yards, measured heights of the centers of each three-shot group above the point of aim, without making any adjustments to the sights/opticals in shooting at those distances.

Bullet weights differed in POIs along the way, as expected.
Velocities made a difference (between 16 & 20-inch barrels).
One gun shot "faster" than another, both with 16-inch barrels.

POIs varied substantially at different distances between the four guns.
Sighting planes can affect impact "rise".

I measured one three-shot group that was a full 14 1/8 inches above point of aim at 200 yards, with that 25-yard zero. I had to aim at the center of the target below to hit the target above.

A 25-yard zero may or may not give you what you want at extended distances.

"Minute-of-man" accuracy?
Even at 100 yards I found 7 and 8-inches of rise in POI vs POA, with that 25-yard zero, with some loads.

The 25-yard zero has never been a particularly good zero for shooting at anything but 25 yards.
If your hostile Minute Of Man is standing still at 100 yards or beyond, out in the open, and conveniently upright, you may have a good chance of a strike.
If he's behind cover, only partially visible, and the light ain't good, it may be a totally different matter.

There is NO substitute for zeroing your gun in your hands at 100, 200, or 300 yards, IF you expect to hit successfully at those distances.

The 25-yard AR zero is not a one-size-fits-all-ARs absolute.
You can also really screw yourself up if you sight one bullet weight in at 25 & then switch to another weight for longer uses.
Denis
 
When I've put a new scope on my gun I get it shooting within a 4" circle at 10-25 yards, just one shot between adjustments, then go out to 50yards and do the same but sight a few inches high, then move out to 100 yards if thats where im sighting in for and then do my 3 shot groups and proper adjustments then.

Don't just stick our scope or sight on a gun and take pot shots at a 100 yard target untill you get it right, that is a great way to waste ammo.
 
DPris, if you zero a standard AR at 25m, it should be high at 100m and 200m, and back down to zero at 300m.

So, you showed high at 100 and 200, but where was POI for you at 300?
 
I have qualified with the M16A1 and A2 since 1975 through 2003 using the 25 meter zero method. I qualified as an expert with the iron sights shooting from 25 meters to 300 meters for the vast majority of those years.

I even had a Colt H Bar AR that I used to shoot at 600 yards using the same zero method and I was able to consistently hit the target.

I just used the method from the Army Warrior Tasks for an M4 and Eotech that I purchased using as close to mil tech ammo as I could purchase. Still works for me.

You are right it is not a one size fits all deal if you use a variety of bullet weights and gun configurations. If you use it within the parameters of what it was designed for it works fine.

The principle of it is that if you are able to shoot consistent groups with one design or rifle and ammo with the same specs then it is just a matter of sight adjustment or using holdover at different distances.
 
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M,
Yes, I fully understand trajectories & that there obviously SHOULD be bullet rise. I'm only half as dumb as I look. :)
Honest.

My point is that it can be substantial and variable between guns, and it CAN be WAY high. High enough to miss a target completely at distance.
I don't think many people understand how much even the relatively flat 5.56/.223 shoots to quite different elevation POIs at various distances, with different velocities, with different bullet weights, and with different guns.

I didn't try it at 300, the state range where I do most of my rifle testing has 100 & 200-yard ranges open all the time. Their 300-yard range is only open one day a week, and it didn't match my schedule.

Woulda been nice to get the whole 300-yard picture, but shooting out to 200 showed me what I was looking to confirm in measurable results.
None of my rifles (in any caliber) will be zeroed at 25 yards. Not even a .22. :)

My ARs are here to be rifles, and they're sighted in to be efficient at longer distances.
Denis

Edited to change one POA to POI. :)
 
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Denis, didn't mean to imply you didn't know the theory, but that I would have liked to see how close the 300 POI was to what the theory would have predicted.

When I did the 300m course of fire from a 25m zero, it was against pop-up silhouettes; we only knew if we knocked them down at intermediate ranges, not where exact POI was. Kind of curious how far from theoretical mean your results were.
 
Eg,
When I was first introduced to the M-16 in '72, we zeroed at 100 yards.
By the time I got out in '76, we were zeroing at the little 25-yard reduced silhouettes.
I didn't like it then, don't like it now.

My ARs are 2 inches high at 100 yards. I don't have to fiddle around with holdover on rabbits out to 150 yards, or do much guestimating at all.
If they were set for 25 yards, I would.

Since I won't be doing any 25-yard shooting to speak of, (rabbits and coyotes don't let me get that close), and a dead-on 100-yard zero will involve no significant loss of efficiency at 25 (should I have to shoot that close), whereas the opposite may not be true, I see no point whatever in handicapping myself.

I also will not be shooting out to 300 yards. I can't see that far with the Aimpoint & don't plan to need the capability even with the Trijicon. Open irons? Forget it. :D
I will never wear a uniform again, I will never go to war, and I'm outa the house-clearing biz.
200 would be my realistic max for most needs, including defensive, and 2 high at 100 will handle that with much more efficiency than a 25-yard set-up.

If I set for 25, figuring trajectory at the distances I'd most likely be shooting at could be up to a foot high, why would I care that it'll drop back down again to POA at 300 yards, a distance I won't even be shooting?

How many AR owners routinely (or ever) shoot to 300 yards anyway? Some, sure; majority, no. If you're not military & you don't shoot service rifle-type competition, you're most likely not going to be lobbing them in at 300. Varminters would be an exception, but if you tried to tell me AR varminters set their rifles up with a 25-yard zero & call 'em ready, I'd have to at least mildly question your sources. :)

My money's on just setting the gun up to put a bullet where I want it at the max distance I'm going to be using it.
Yes- you can hit at distance with a 25 zero, but my opinion says you'll probably have to work harder (range estimation & holdover) to do it. Especially on smaller targets out there a ways. I'm lazy, I'll just sight in the gun for where I want to hit in the first place & keep it simple. :)
Denis
 
M,
Woulda been nice to do 300, but the timeframe I had to work in just didn't match with the facility's schedule. Dunno why they keep that 300-yarder closed most of the time, but I did the best I could out to 200.
I spent as much time as I could on the project, had to get it done & move on.

Even at 200 & closer, POI vs POA was markedly different between guns. Enough so to point out clearly (at least to me) that you can't just grab that 25-yard zero & run with it for any & all ARs and expect everything to shoot the same. Not even with the same loads.
Denis
 
I have an old 1973 Gun Digest annual book. It contains a ballistic table which shows when the bullet first crosses line of sight and the above or below line of sight at various ranges.

I have used this table to sight in my 243 for over 30 years. It is very effective to zero at first cross and then confirm at the extended range.

You can probably find a similiar table on line.

For my AR I use the military system. It is very effective. You must, however, remember the accuracy limitations of your rifle and its sighting system.
 
Generic tables can't take individual rifle & bullet configurations into account.
They can be useful as a starting point, but I'd maintain they are no substitute for actually shooting your gun at the distances you want it to work at.
"Confirm at the extended range" is the key, with which I could not agree more. :)

Denis
 
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