So I am confused. POI change on AR from 50-100 meters

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jbkebert

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I had posted somewhat recently that I had purchased a Stag model 1 AR-15.

I had many many questions about this that and the other thing but here goes another one. I picked up a Bushnell Trophey red-dot scope (Yes I know there are many others that are much better qulity.) However it was just something cheap to mess around with. The scope is dead nuts accurate at 25 and 50 meters. I mean sub minute of grain of rice. Sucker shoots well.

However at 100 meter I am shooting 5 inches high and 4" right. Granted the dot is huge at that distance so precise shot placement is a little hard. I am still grouping so the offset is consistant. Printing around 1 5/8-1 3/4" at 100. For the sight I am using I am not terribly upset about the groups.

So riddle me this batman the rifle being a 16" carbine with a 1:9 twist shooting a 55 grain FMJ. Tried three types of ammo all having the same offset of high and right. (Tula, Federal XM193 55 grain, Remington UMC) all of which were preforming in a similar manner. So why would this setup go from dead on at 50 to that far off target in just another 50 meters. Shooting on a 82-85 degree day 10-12 MPH crosswind. Shooting in a bowl that is fairly well protected from wind. Humidity 82%.

I have had someother instance with this rifle. My POI from standing, sitting, prone seems to change. My cheek weld is the same I am no where any close to being a novice shooter.

Should I just chuck the red-dot and go back to open sights or the Millet DMS scope has some appeal to me. I friend of mine has the millet scope and it seems to be a good compromise between fast target aqusition and accuracy a a little longer range.
 
A couple things to try:

1) Turn down the dot until you can barely see it. Then use the top (or bottom, it doesn't matter as long as you're consistent) edge of the dot as your aiming point.
2) Zero the scope at 100 yards. Use that for a zero and accept the smaller offset closer in.

Just curious, what results do you get with the irons? Cheap optics can distort the target image in funny ways...

BSW
 
With irons shooting from bench, prone, and sitting I am getting a slightly smaller group around 1 1/2 sitting and prone shooting with a GI web sling. Bench 1 1/4 or so prehaps 1 3/8". POI is no where near that far off. Shooting perhaps 3/4" high and a 1/2" right. I fired 200 rounds yesterday at the range. And fired about 150 rounds less than a week ago with Irons.

Anyone have anything good or bad to say about the Millet DMS scope??

Also shooting with the least amount of light through the red dot as I could see. Tried both red and green. I could see the red a with a little less intensity.
 
Move the Bushnell over to a .22LR and save up for a Aimpoint?

You'll cry at the price but never at the quality.

I suspect more money has been wasted over the years on ammo trying to dope out crap optics than was saved by purchasing said optics.

BSW
 
If you zero your rifle at twenty-five or fifty yards, your zero needs to be absolutely dead-nuts on. Small errors at close range have a way of becoming big errors at longer range. I always recommend zeroing your rifle at the longest range you have available.

It's also certainly possible that you're having scope troubles. The Bushnell Trophy red dot isn't exactly known for scintillating quality. But first, I'd take the rifle out and zero it at 100 yards, 200 if you can, then see where it's hitting in closer.

It's not unusual at all for your zero to wander a bit going from position to position. Do your zeroing from the position you shoot from most often, and keep in mind the changes for different positions.

-C
 
I believe red dots were designed to put rounds on a man sized torso out to 200 meters. They are made for speed not accuracy, now you can spend $ and get a better sight but to some degree until you get to the $500 mark you will experiance this with nearly* every red dot.
BrianSmithWins has some good things to try with your sight.
The more you turn the reticle (dot) up the more bleed over you will get and then your ability to make a consistant reticle lay on your target is harder.

So then you need to come back and say "What is this sight/scope going to be used for?"
Perhaps you would be better served with a conventional scope?
Thanks
A/M

* There are few bargains in red dots, not many, but the sparx does stand out. For the money you get some good quality.
 
The rifle will probably not be used for any long range work. Heck if I want accuracy over a long range I'll grab my Cooper or my Savage 12bvss.

A home defense carbine I don't think is really all that much of a necessity either. I live in a rual area but really do I need a 30 round mag for a bump in the night. More often than not it will be a plinker or a coyote oppurtunity rifle. Has anyone had any experience with the Millet DMS.

I like the concept of it. However my buddies is mounted on top of the carry handle of his AR with see through optics. So no chance for a positive cheek weld this thing was more stretch your neck as far as possible to get high enough to see through it. So accuracy was not nearly at its best. ALthough if this scope was mounted on a flat top with a 3/4" block it would still provide a decent point of refrence for repeat accuracy.
 
I'd go with what Brian said about www.primaryarms.com

I bought an Aimpoint clone with a x3 flip to side magnifier with mounts for like 185$. They are also like an hour down the road so i stopped by their shop, and they are a pretty small mom and pops operation. I'm completely impressed and happy with the optics I got at the price point.
 
Has anyone had any experience with the Millet DMS.
Click to expand...

I've got The Millet 1-4X DMS on several rifles. Short answer is I like them very much.

Put it at 1X and turn on the red dot and you can shoot very quickly with both eyes open. With the dot off and set to 4X I find it a good scope. I like the reticle and its range estimating features (once you've read the manual a couple of times), but that is not everyone's opinion.

My only complaints are its a good bit larger than I had expected (but that hasn't stopped me from getting more of them) and I wish the depth of field in the eye relief was a little greater.

My 60 yo eyeballs won't make and claims as to "clarity" but I can see better with it than without it, and .223 holes are visible at 50 yards with it set to 4X. I think its a very good scope for the money, Midway often has them on sale for ~$200.
 
First, if you are on at 25 or 50, you will be high at 100.

Secondly, if there is a POI change that is not attributable to trajectory or wind, it is probably a parallax error.
 
I would say, take it to 100 yards, zero it there, then take it to 50 and 25. like others have said, even a small zeroing error at 50 yards will only grow at 100 and 200 yards. My feeling is that the dot is off just enough to throw you off at 100.
 
Most of the time I will sight in a new rifle at 25 yards. Just to get rough adjustments taken care of. It is alot faster to get on paper and get in the ball park. I can see bullet holes with the naked eye so no time spent looking through a spotting scope trying to see .223 holes.

I did this and then moved to the 100 meter line. At first I could not find a single hole in my target at 100 yards. After 20 rounds and scratching my head. I just started using Kentucky Windage to see if I was shooting high, low, right , left. After a few rounds I figured out at least what I needed to do. So after making way to many adjustments to get on target at 100 yards. I moved back to 50. Now the POI is low and left but not nearly to the degree that I was at 100.

Yes I understand that a 25 or 50 yard zero will give me high hits at 100 yards. Certainly not 5" + closer to 7" before making some adjustments. My .22-250 doesn't shoot that fast to gain that much height.

I just gave up and mounted a Nikon prostaff 3-9-40 that I have extra. Scope has never been mounted and has just been sitting in a drawer waiting. I may put the Bushnell on a turkey gun or something else.
 
After a few rounds I figured out at least what I needed to do. So after making way to many adjustments to get on target at 100 yards. I moved back to 50. Now the POI is low and left but not nearly to the degree that I was at 100.
Click to expand...
Yup, what Zak said. You've got parallax problems. I bet the new scope (or a switch to irons) fixes things.

-C
 
The scope is dead nuts accurate at 25 and 50 meters.
Click to expand...

To be zeroed at 100 yards, the scope should be shooting more than an inch low at 25 yards and slightly low at 50 yards. Remember that the scope is 2.6" above the bore, so if its zeroed at 25 yards, then the bullet has risen 2.6" in 25 yards. It will keep rising until well past 100 yards, so with a 25 yard zero it will be 7 to 9" high at 100 yards. It won't fall back to zero until about 300 yards.

There are several methods of zeroing an AR. I like zeroing POA/POI at 50 yards. The gun will shoot an inch or so low at 25, a couple of inches high at 100 and more or less dead on at 200. That means that POI will be within 2 inches of POA from 25 to 200 yards. Close enough for government work.

If I can hit a six inch plate offhand consistently at 100 yards with irons or a simple red dot, I'm happy. Most 5.56 ammo loses considerable terminal effectiveness past 125 to 150 yards. For serious business past 150 yards, use another caliber or save your ammunition until the target moves closer.
 
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This is quite simple. if you follow the steps..
Federal XM193 55 grain is very accurate and zeroed at 100yards should give you a point of impact 1 mil low that is precisely 1.8 inches below your zero. In reality this will be something like 1.1 but it is so close that you add another .5 for sight height and you get the correction right.
The same way the point of impact at 200 yards is going to be below the 1 Mil dot. that is 9.75" and depending 3/10th below with army dot.
10MPH wind windage correction is.. (assuming crosswind you meant 3 or 9 o'clock)
2.38" at 100 (try 9 clicks 1/4moa clicks)
8.68 at 200 (try 17 clicks)
If you are zeroing with wind then take this windage off your scope but I suggest you zero one day w/o or minimum wind.

Federal XM193 55 grain - 100 yards- DTI 16" heavy barrel NC M16 BCG.

100_6844b.gif

100_6841b.gif

If the scope doesn't do it then get a good scope. You do not have to break the bank to get something that produces results at those ranges.
 
I have a Millet DMS-1 and have had it on several rifles over the past couple of years. The things I am not impressed with first:

1. It is heavy....I was surprised at how heavy it was.
2. When new, the illuminated reticle was NOT bright enough to see on a sunny day.
3. It took a tumble (about a 2.5' drop) and has had no functioning illumination since.
4. You can see distortion at the edges of the glass.

Now the better things about it:

1. It didn't really matter that the illuminated recticle stopped illuminating....the dot in a donut reticle shows up nice a black on a bright day and it works just fine without battery lighting.
2. The price is pretty good for a 1-4x optic.
3. The distortion doesn't really bother it give the zoom range.

Bottom line....it is a made in China optic.

I'm not sure if I would purchase another one, but I don't regret getting this one. For the money, it is OK if you are looking for a medium range, reasonably priced optic. It was replaced with an ACOG and the DMS-1 now resides on the backup AR, as does a number of displaced hand me downs.
 
So another question for all you AR experts out there. I mounted the Nikon like I said before. The set of Weaver rings I have do not tighten up enough on the 3/4" block I had purchased to give me bottom 1/3 cowitness with the red-dot. I am not sure why but it is narrower compared to the flat top picatinny rail.

So I a set of extra high rings I just mounted on the flat top without the use of the 3/4" block. Just messing around to see how it would look. I can't see the front sight post even on 3x setting. I understand that it is because the focus point is well in front of the front sight. My question is this. With the extra high rings alone the cheek weld feels pretty good. Now granted the front sight post in somewhere in the middle of the cross hairs even though it can't be seen. If I don't buy another set of rings that will work with the 3/4" block can I just shoot it as is. Or will this screw something else up??


You know its pretty sad. I spent 11 years in the Army 4 years combat arms. Every time I qualified I made expert. Now I can't seem to figure out what shoulf be a pretty simple system. Perhaps this is why I prefer bolt guns. Before the armorer did what he did and handed it to me to shoot. Good thing I was not the guy in the arms room.:confused:
 
A 3x9 magnification scope cannot be used for co-witnessing iron sights.
It is too close to acquire any focus for the lenses. So it doesn't matter if you have it perfectly aligned with the front peep the only thing you will get is a useless shadow if anything.
If you want "options" use extra low irons or a 1 o'clock T1 reddot or similar for CQ so you can alternate.
 
Not wanting to co-witness sights with a scope. Was more thinking leaving the Ar for a dedicated plinker/coyote rifle. I was having alot more luck with the standard carry handle peep sights.

Will the scope being in-line with the front sight post even though I can't see it screw up the use of a regular scope. Will it throw off focus on a target say 50-200 yards away.

Or should I purchase another set of rings that will tighten down on the 3/4" block and use it in addition to the x-high rings?

Sorry for the novice questions but I certainly do appreciate the help. By the way nice groups on the above picts.
 
Most scopes are parallax free at 100 yards at 25 and 50 the dot would move with your eye position.

Simple check look through scope at 25 yards and move your head side to side, if the dot moves it is not parallax free at that distance. Check and do the same parallax test at 100 yards.


Parallax

A condition that occurs when the image of the target is not focused precisely on the reticle plane. Parallax is visible as an apparent movement between the reticle and the target when the shooter moves their head or, in extreme cases, as an out-of-focus image. Bushnell center fire riflescopes under 11x are factory-set parallax-free at 100 yards; rim fire and shotgun scopes at 50 yards. Scopes of 11x or more have an adjustable objective to adjust for parallax.

http://www.bushnell.com/products/scopes/riflescopes/tech-talk/
 
Three things:
1. Heigth of line of sight over bore (usually 2.5-3.0" on AR15)
2. Parallax (looking through scope at an angle to centerline axis) This is why high end target scopes have the extra focus ring to eliminate parrallax at a given distance to target. Most "fixed" parrallax scopes are set at 100 or 150yds. Pistol scopes and "Shotgun" scopes ususally to 50 or 100yds.
3. Canting of rifle. (tilting rifle while sighting through scope) Axis of line of sight through scope must be verticle (perfectly perpendicular) over line of bore. This is why long-range competitors often have a spirit level installed somewhere on the rifle to ensure that rifle is being held perfectly level verticle axis.
 
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