Eotech's Lost Their Zero After 3 Years on AR's

[Silver Jack Hammer]

My police department bought about 45 new AR’s and mounted new Eotech’s on them about 3 years ago, they were zeroed. Now they all hit 5 inches to the left. Puzzling. Personally I declined the issued AR and kept my iron sighted 16” barrel Colt. The dept. bought the short stubby 10 inch barrels.

Anybody have any experience with this? I don’t know if it is due to the roof mount where the rifles have been laying on their sides while the patrol cars have been bumping down the roads lights and sirens for 3 years.

[Jailer]

You sure they're not counterfeits? Some of the clones out there look real close to the real deal.

I'd be contacting eotech for some assistance on this one. They shouldn't be out of zero from riding around in a roof rack.

[tomme boy]

Have you tried to re zero them? I don't like them. I like Aimpoints. Never had a problem with them.

Why did they chose a 10" model. Useless unless they are running a suppressor with it. I would not want to be anywhere near that while it is going off. Outside would not be that bad, but inside a structure would not be nice.

[scb]

I wouldn't think this is the case but, there was a problem years ago with m16's having bent barrels. It was found that the culprit was the rifle racks they were being locked into. If they ALL exhibit the SAME problem they might want to look into that.

[Larry Gibson]

All such sights (scopes, dot sights, etc.) can get knocked off zero. However I find it strange all are hitting 5" to the left. That tells me something is different other than the Eotech's. 1st, have the batteries been changed? mostly I'd suspect something different in the ammuntion. As an SF weapons/Operations/Intell NCO for many years I've tested enough different dot sights and lots of M193 and M855 in numerous ARs and M16s to know that a 5 moa POI change from different lots of ammuntion is not uncommom. That they all hit the same 5" left in this case of the original zero leans me in that direction.

I've used about all the dot sights and was impressed enough with the Eotech to buy my own before deploying to Iraq in '04/'05. Mine was mounted low over the front handguard of my M16A2 with a C.R.T.C. BC-Cam mount. That enabled the dot to be coaxial with the iron sights. After zeroing with the iron at 300 meters I adjusted the dot to sit on top of he front sight which then gave a 250 meter zero for th dot. When using the dot I mostly just looked over the top of the rear sight aperture. However, an instant check of the Eotech zero was easily made by simply using a normal sight alignment with the iron sights. If the dot was still sitting on top of the front sight it was good to go. I did rezero both as different lots of ammo were used but once zeroed I got enough of that lot of ammo for 2 basic loads at least....usually more. Once zeroed I never found a shift of zero with the Eotech in 16 months of hard use. I never had a battery problem with the AAs either.

Since returning home I have used the Eotech on several ARs with complete satisfaction. It currently is right beside me on my go to/traveling AR for varmint hunting and protection. The zero has not changed as long as I stick with the original load or lot of ammunition.

Again, given all of your ARs (45?) now hit the same 5" left I would suspect the ammo and not the Eotech's. Figure the odds of all of them malfunctioning exactly the same at the same time? Something else was changed that caused the zero shift.

Larry Gibson

[W.R.Buchanan]

The batteries are the other variable. Dot sights do weird things when the batteries start dying.

The one on my new Kel-Tec SU-16 had a dot that looked like a flower. It is a cheap UTG $30 sight, but just putting a new battery in it yesterday made the dot round and sharp again.

I did night ops in my front yard last night and it is amazing how fast you can aquire a target in the dark with this type of sight.

With 45 of them whacked out at the same time there is something else they have in common. It ain't the Eotech's.

Randy

[Lloyd Smale]

I too find it about impossible that all 45 are hitting 5 inches to the left. Did your dept happen to buy a differnt brand of ammo or maybe even are using ammo out of a differnt lot. Differnt ammo can move the point of aim that much. Im not a big fan of eotechs but id be the first to tell you that they are a quality sight.

[Silver Jack Hammer]

Thanks for your input. The rifles are being re-zeroed. If we can identify the culprit I'll pass it on. Right now were still scratching our heads.

[Moonie]

I'd bet on an ammo change

[garym1a2]

Any chance the same person zeroed all 45?

Thanks for your input. The rifles are being re-zeroed. If we can identify the culprit I'll pass it on. Right now were still scratching our heads.

[runfiverun]

i'd say that was some hellaconsistent manufacturing if they all stress relieved at the same time.
i'd say ammo too or the racks they are being carried in is causing issues.
the racks would cause gradual change.

[Artful]

Thanks for your input. The rifles are being re-zeroed. If we can identify the culprit I'll pass it on. Right now were still scratching our heads.

So did you figure out anything?