Went to the range today to zero my Eotech. It's mounted on the carry handle of a Colt MT6601C. The club I'm in will only allow 1 round in any rifle at a time. I was shooting at 50 yards with a friend spoting for me. It was zeroed quickly and I was shooting 1" or less groups. Then the group shifted 2 inches right and an inch high. Same tight group, just moved. I waited 2 or 3 minutes and fired another 5 rounds all in the x ring. All shooting was off of a shooting bench with a rest. There is nothing on the sight that is loose. My friend said maybe it shifted due to heat but the rifle was only about 105 degrees F as I was shooting very slowly. Any suggestions?

Is it securely mounted?

No joke, check the simple and obvious things first.

Mine came loose the first time at the range.

Yes. I can't find anything loose anywhere. I'm using the ARMS #2 mount. I know the AR is fine because if I use the irons it hits where aimed.
Have you ever heard of anyone else with an Eotech that did this?

I had one of the ones I dialed in come loose at the range as well. If you already checked that, shoot eo-tech a note and they'll get you squared away quickly. If you can post the problem once you hear from them it would be much appreciated!

I will contact Eotech and update. Thanks for the help

I had exactly the same problem occur with mine. It did fine until I mounted it on an Ultimak forward mount on an AK 47. At about 200 rounds the Sight (a brand new 552) began turning itself off. I took it off the gun and it cooled down. Put it back on and when the whole set up warmed up again same problem.

Shortly after that I removed the sight from the AK and put it back on an M4 pattern. Zero began shifting every time I would shoot it. I returned it to Eotech and they told me it was a defective windage mechanism. But I must say I got it back in less than one week and have had no problems since of any kind.

Well, I don't know.  I sent my EOTech back for repair because the damn thing wouldn't turn off.  When I received the sight from EOTech I simply mounted it back on my rifle(flat top) and it was still zeroed.  Kick ass IMHO.

Joe

ZX12R - I don't mean to highjack your thread but have you seen the 2004 ZX10R???  OMG is that thing awesome.  I may have to dump all my ARs and buy one [;)]