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View Full Version : Is it eotech, rifle or shooter


The Russian Rocket
05-16-2010, 10:50 PM
I need some answers from those of you who know what you are talking about.
I have taken my AR to the range on Saturday.
At 100 yards there were a bunch of clay pigeons laying around. I was using my eotech sights from the bench with all the comfort and pillows and hit 5 or 6 of them no problem. Immediately I became a legend in my own mind. I was pretty happy for a while as I continued shooting into paper. 100 rounds later I noticed I am shooting slightly to the right. So I adjusted eotech 1 click to correct it. Some 50 rounds later I noticed my groups dropping down a couple of inches. So my question is this. Is it eotech that is loosing zero all the time or is it the rifle getting hot or dirty? At a 100 I am still within 6 circle but I have seen better.
Should I be cleaning the bore after so many shots? Is it normal to constantly adjust eotech? I hope not. What do I do to zero in the rifle and never have to do it again while shooting happily thereafter?

Noobert
05-16-2010, 10:52 PM
I'm guessing you as the shooter is the problem

paintballergb
05-16-2010, 10:55 PM
That's not normal. First I would ask if you're sure that it's a legitimate eotech.

joelogic
05-16-2010, 11:01 PM
No you dont need to clean your barrel after that many shots.
No you dont need to adjust the eotech that often.
Its always best to be scientific when troubleshooting these problems.
1. Same ammo through test?
2. Same results with iron sights?
3. Where you moving around?
4. Adjusting stock position or checkweld?

The eotech should be extremely forgiving with eye alignment. I think they are parallax free after 25yds. Rounds definately shift due to heat and other mechanical factors. Sometimes 2-3MOA is the best the rifle/ammo/shooter can do. But if you are shooting tight groups but your groups can moving it must be loose mounting of the eotech or sloopy shooting technique.

Zeroing: zero irons, move dot on front post, lower iron sights, zero eotech, raise iron sights, and verify.

Sidenote: I leave my rear iron up to act as a ghost ring rear sight for my eotech because it helps reinforce proper shooting technique.

818gtiguy
05-16-2010, 11:02 PM
Make sure it is TIGHT on the rail.

Noah3683
05-16-2010, 11:05 PM
My guess is shooter error. once zeroed, I have removed my eotech at least 8-10 times and slapped it back on without having to re-zero. If it isn't shooter error, my 2nd guess would be fake eotech or severe problem

BunMaster
05-16-2010, 11:11 PM
Make sure it is TIGHT on the rail.

+1. my Eotech was sliding around on me without me noticing. I noticed it was just ever so slightly loose, enough to throw some interesting groups.

The Russian Rocket
05-16-2010, 11:15 PM
I hope it is me and not the eotech. How do I know if it is fake or not?
I use the same ammo. 5.45 Russian stuff that they failed to use in Afganistan.
I did not move to another seat. I never moved my stock. The groups are usually very tight. But they moved from time to time.
Thanks for your input.

The Russian Rocket
05-16-2010, 11:19 PM
Joe, where do you get the time to read all these threads?

LloydXmas250
05-16-2010, 11:19 PM
Make sure it is TIGHT on the rail.

+2
I once had an optic zeroed in and I was a god with it. Started missing and then started fiddling with my zero all while not noticing it had come loose. Re-zeroing it again was not fun.

The Russian Rocket
05-16-2010, 11:24 PM
Against instructions by eotech I used lock tight and really screwed it in tight. I doubt it could move. I am afraid if i make it any tighter I'll destroy the thread.
What is the way to find out if I got a fake one or not?

Noah3683
05-16-2010, 11:24 PM
The reticle is usually the biggest giveaway as a fake. You can also call them and check the serial #. Also 5.45 surplus isn't always the most reliable for grouping. In fact most surplus isn't. They were made to be "accurate enough" with an emphasis on cheap. The same can be said for m855 and xm193. You want tight consistent groups, buy match ammo

The Russian Rocket
05-16-2010, 11:28 PM
You might be right on this but I own anything I can see, padlocks, rocks from a 100 yards with this round and this rifle. Some say that Wolf 7.62 X 39 is crap but my body makes tight enough groups at 200 yards with his 7.62 AR no problems while saiga with the same caliber is all over the map.

Pryde
05-16-2010, 11:31 PM
Where is your Eotech mounted?
If it is mounted on the forearm, heat may be the culprit.
A friend of mine had a similar problem, when the Eotech gets really warm the plastic seals will melt and screw with your zero and could possibly kill the sight.

Also be aware that putting pressure on your barrel/forearm (assuming its not free-floated) by either resting it hard on a table/barricade or slinging it really tight will affect your point of aim.

Another possibility is that your barrel nut may be loose, I would check that too.

yock
05-16-2010, 11:31 PM
I say it is the whole setup you should give it to me and start over!


Just kidding I bet it's the ammo myself but try some match ammo and probably get better same thing with me and it was the ammo.

Noah3683
05-16-2010, 11:35 PM
99% of the time you will find 7.62 ar uppers are far more accurate than saigas and ak's. Ar uppers are built with tighter tolerances and better precision. Ak's rarely jam because they are loose to begin with

BunMaster
05-17-2010, 1:50 AM
http://www.eotech-inc.com/counterfeit_notice.php

there's a link to a PDF containing photos to help spot the fake.

GM_77
05-17-2010, 9:25 AM
So when you say your groups are shifting low or to the right how large are those group sizes and how many shots?

Is your AR barrel free floated?

KaLiFORNIA
05-17-2010, 10:26 AM
Soooo was it legit or did u get a clone?

windrider
05-17-2010, 10:39 AM
it could be your yanking your trigger to hard (if your right handed) I notice that when I dont do a nice slow steady squeeze I shoot low and right

joelogic
05-17-2010, 11:30 AM
Rocket, I make time to help you newbs out.

The Russian Rocket
05-17-2010, 11:43 AM
So when you say your groups are shifting low or to the right how large are those group sizes and how many shots?

Is your AR barrel free floated?

The barrel is not free floated. Groups are 2.5" 3 to 4 shots.

The Russian Rocket
05-17-2010, 11:46 AM
Soooo was it legit or did u get a clone?

I sent serial # to eotech and they say it is legit. I am gonna check if it is loose today and if not will probably send it to them to have a look at.

bombadillo
05-17-2010, 12:03 PM
My guess is something else other than the EOtech being loose. If it will zero for 50-100 rounds then suddenly lose a zero, it seems that something else is going on. I would expect a gradual change from a shifting sight, but not 50 rounds right on and then a sudden difference. How fast are you shooting? If you're rapid shooting and its a light barrel, you may be getting some POI change due to a hot barrel.

The Russian Rocket
05-17-2010, 3:50 PM
Thank you all for your replies. You are gold.

nicoroshi
05-17-2010, 4:20 PM
Make sure it is TIGHT on the rail.
This^^^
I have a 5.56 rifle with an EOTech + x3 multiplier as well as a flip up iron sight behind it. I was having very similar issues to what you describe.

The front of the EOTech spanned between the upper receiver, and railed YHM FF tube. At the time I had a vertical fore grip on the tube. After shooting a while the tube would move (ever so slightly) on the barrel nut (even though it was well tightened with a strap wrench) taking the front of the EOTech with it, and it would lose zero by about 1/2" at 100 yards.
My issue was resolved by putting a set screw through the FF tube, and into the barrel nut as well as removal of the VFG.
Made a mental note to self to only buy monolithic uppers/rails or ones that bolt to the upper receiver in the future.

My thinking is something like that is occurring with your rifle.
Check the mount for the EOTech, and ensure it's rock solid.

The Russian Rocket
05-17-2010, 5:19 PM
This^^^
I have a 5.56 rifle with an EOTech + x3 multiplier as well as a flip up iron sight behind it. I was having very similar issues to what you describe.

The front of the EOTech spanned between the upper receiver, and railed YHM FF tube. At the time I had a vertical fore grip on the tube. After shooting a while the tube would move (ever so slightly) on the barrel nut (even though it was well tightened with a strap wrench) taking the front of the EOTech with it, and it would lose zero by about 1/2" at 100 yards.
My issue was resolved by putting a set screw through the FF tube, and into the barrel nut as well as removal of the VFG.
Made a mental note to self to only buy monolithic uppers/rails or ones that bolt to the upper receiver in the future.

My thinking is something like that is occurring with your rifle.
Check the mount for the EOTech, and ensure it's rock solid.


Number 1: I love your signature. Was it from Mark Twain or Franklin?
Number 2 I am not sure I understand everything you said. I'll have to ask someone. Too technical for me. I am new to this. I know how to shoot only :) Here is what I have and eotech is on the rail.
What do I tighten? http://www.topgunsupply.com/smith-wesson-m-p-15r-5.45x39-rifle.html

nicoroshi
05-17-2010, 7:09 PM
The quote is from AnimalK from Glocktalk.

Seeing as you do not have a free floated front tube on your rifle... is the EOTech mounted far enough forward to be over or touching the forward grip?
If not then look into the other suggestions of barrel heating up (rapid fire) or pressure exerted on forward grip during firing.
My guess is the latter of the two.
(One of the main advantages of a free floating forward tube is better accuracy due to not being able to exert pressure on the barrel via the forward grip).

The Russian Rocket
05-17-2010, 7:17 PM
The quote is from AnimalK from Glocktalk.

is the EOTech mounted far enough forward to be over the forward grip?



yes my eotech is over the forward grip, not touching it of course. You think this is my problem?

nicoroshi
05-17-2010, 7:32 PM
I doubt it if it's not touching the the fore grip.

Look into the other suggestions of barrel heating up or pressure exerted on fore grip during firing.

Noah3683
05-17-2010, 9:21 PM
Eh you can see mine in my avatar. Half of it is mounted directly to my aluminum quad rail which gets much hotter in the area than the plastic handguards. I've never had this issue