Recently, the SOF WPMO at NSWC Crane has issued a warning about EOTech optics, saying that they experience problems with temperature sensitivity and shifting zero. SoldierSystems.net reports (only a portion of the article is duplicated below, please click through and read the whole thing):

Over the past few weeks, three separate issues have come to our attention regarding EOTech’s line of Holographic Weapon Sights (HWS). While we initially thought they weren’t related as they came up one by one, we realized they were all connected once we had looked into all three. Consequently, we believe they should be presented together, along with the source documentation.

Safety Of Use Message Issued
Although it’s the last one we uncovered, we’ll begin with the most glaring piece of information. On 14 September, the SOF Weapons Program Management Office at NSWC Crane released a Safety of Use Message regarding issues with EOTech’s Enhanced Combat Optical Sights (ECOS), which is how they refer to HWS. This certainly caught our attention as the PMO is responsible for USSOCOM weapons. That message ultimately serves as the linchpin, tying together the other two issues we’ll soon address.

This critical bit of information would have been a stand-alone article, but it added credence to the others and offered coherence to some otherwise inexplicable issues. It also allowed us to concentrate on the facts presented in the various documentation. We will introduce the other issues after you get a chance to read the SOUM, which was obtained by Soldier Systems Daily. The Message has no date-time-group but was transmitted via official email traffic to SOF units on 14 September, 2015 and there are no markings limiting distribution.

Click to view .pdfWhile there is a great deal of information in the SOUM, two glaring issues stick out. The first is the reliability of the HWS in extreme temperatures, referred to as “Thermal Drift”. The PMO has noted a +/- 4 MOA shift at -40 Deg F and 122 Deg F. Second, is the concern over the claim by EOTech that their HWS are parallax free which was the subject of a previous Safety of Use Message from the same office issued 16 March, 2015. In this case they noted between 4 and 6 MOA parallax error depending on temperature conditions. Despite the PMO working with EOTech to rectify the issues, they still have not been resolved.

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Putting It All Together
As you can see, the three pieces of information certainly seem related when presented together. In the same quarter, EOTech changed their HWS user manuals and acknowledged in an SEC filing, “aggregate liability of $26 million in anticipation of a settlement related to a product specification matter regarding a holographic weapon sight product…” In the next quarter, USSOCOM issues a Safety Of Use Message that addresses the very information removed from the HWS user manuals.

Data Was Right There In The Open
The documentation was readily available prior to its publication here, to anyone who knew where to look. While EOTech has made no public statements so far, regarding the issues with the performance of their family of HWS, they certainly haven’t hidden them either. To the contrary, we wouldn’t have discovered the issues so easily if they’d tried to hide them. They’ve published new versions of their user manuals and made them available to the public, as well as making an SEC filing which is public record and acknowledges there is an issue afoot. While it would be nice to see EOTech publicly acknowledge the issue, it would be interesting to find out how long they’ve known about it. Regardless, the only thing that remains up in the air, is whether L3 Communications will be required to pay that $26 million, to whom they would pay it, and if there will be any additional stipulations.

Let’s Hope They Fix It
In closing, we suggest that both commercial and military users of EOTech HWS read the SOUM, since EOTech has still not specifically addressed its customers regarding the issues. We hope that they do soon and offer a solution to rectify these issues.

In the same price bracket as red dot optics from well-respect manufacturers such as Aimpoint and Trijicon, EOTechs have received polarized reputation, tending to be either loved or hated. While those who favor other brands may certainly feel better about their choices, I doubt most casual civilian EOTech users will notice any problems; they seem mostly to concern military and law enforcement users who use their rifles and optics in a wide range of conditions.