http://soldiersystems.net/2015/09/30/something-is-amiss-at-l3-warrior-systems-eotech excerpt from pdf: http://soldiersystems.net/blog1/wp-...ETY-OF-USE-MESSAGE-14-September-2015-Copy.pdf The purpose of this safety of use message is to inform the operational community that the Program Office has identified performance issues with the ECOS systems which may affect the aiming precision of these optical devices. The ECOS systems performance issue is Thermal Drift which affects point of aim point of impact as operating temperature changes Thermal Drift - After zeroing the ECOS systems at or near ambient temperature (73°F), the zero position will shift during operating temperature changes. The ECOS systems have the potential to shift approximately +/- 4 Minutes of Angle (MOA) at -40°F and 122°F. Due to thermal drift, the sight may not return to zero. The systems have the potential of approximately a +/- 2 MOA zero shift upon return to ambient (73°F) after being exposed to any temperature between -40°F and 122°F temperatures. Fading Reticle - The complete 65 MOA ring with 1 MOA dot reticle may not be visible to the operator throughout the entire viewing window of the ECOS-Q optic. The ECOS-Q system’s age and environmental exposure are factors which accelerate reticle dimming. Impact to operators is the holographic reticle may not be visible in all firing positions. Parallax Error – Parallax is an apparent change in the position of an object resulting from a change in position of the observer. The 65 MOA ring with 1 MOA dot reticle point of aim will appear to move in relation to your target during off-axis firing positions where maintaining cheek-weld and sight picture is not feasible. The ECOS-Q system has the potential of approximately 4 Minute of Angle (MOA) parallax error at 70°F and approximately 6 MOA parallax error at 5°F. Impact to the operators is the point of aim / point of impact will be affected by a MOA parallax error, in off-axis firing positions at all temperatures.