Iron Brigade

Iron Brigade

Specifying A Holographic Sight

At first glance the sheer scope of the range of holographic sights can be intimidating. Each model, however has a unique combination of a small number of features. The features are as follows:

Compatability with night vision. There is no point in paying for night vision settings if you don’t need them. The XPS2, 512, 516 and 517 lack night vision.

Price. The cheapest Eotechs are those lacking NV settings – the XPS2, 512, 516 and 517 again.

Close mounting capability. To allow very close mounting of night vision devices, some Eotechs have their buttons moved to the left hand side of the unit from the back. These models are the EXPS series, 556 and 557 (the 516 and 517 have this feature but are not night vision capable).

Height of the sighting plane. To enable co-witnessing in the lower third of the sighting window and to allow greater compatability with NV units, Eotech ship some models with a 7mm riser.These are the 516, 517, 553, 555, 556 and 557. EXPS series sights are 7mm higher than the XPS..

Mounts. The holographic weapon sights come with one of three mounting systems – allen bolt, thumb screw or QD quick release lever. Thumb screw models include the XPS series and the 516, 517, 556 and 557. Throw lever QD models include the EXPS series, 553, and 555.

D-ring clearance. Some Eotechs are made so that their battery housing is cantilevered to clear the Delta ring (the ring that retains the handguard) on AR15/M16/M4 rifles. The XPS, EXPS, 516, 517, 556 and 557 are designed with this feature.

Length. Eotechs vary greatly in length. This is an important consideration with night vision rigs. The AA battery models are longest, followed by the CR123 battery models and the shortest are the XPS and EXPS models. The XPS and EXPS are 3.5″ long, the 553 4.9″, the 556 5.0″, the 512, 516 and 552 5.4″and the 517, 555 and 557 5.6″.

Ballistic reticle. Only three models have ballistically matched dots – the 557.AR223 is matched to the .223 round, the 552.XR308 to the .308 Winchester and the 552.XR500 to the .50 BMG. The 557.AR223 has side mounted brightness and NV buttons whereas on the 552.XR.308 they are mounted at the rear. The XPS2-2, XPS3-2 and EXPS3-2 offer a 2 dot reticle but this is not matched to a specific cartridge.

Batteries. Eotech have abandoned the use of ‘N’ batteries and now boast far greater battery lives. You need to choose between the AA and CR123 with some models only differing in which they use (for example the 553 and 555). The AA has significantly longer battery life when used with lithiums (1000hrs vs 600) but CR123 models are more compact. A single CR123 (transverse) is used in the XPS and EXPS series, two CR123s in the 516, 553 and 556 and two AAs in the 517, 552, 555 and 557.

DoD type classification. The main military use models are the 552 and 553 series – the latter specifically designed for and used by United States Special Forces COMand (SOCOM). The 555 is an AA battery 553 and thus shares its heritage.

Color. The 512 series is available in black, Mossy Oak and Advantage Timber camoflage. The 553.A65 is available in black or tan.

Integrated laser. Only the EOLAD series have integrated lasers.