Choosing A Red Dot Sight For A Rifle

Reflex or ‘red dot’ sights have become extremely popular with civilian shooters and are now ubiquitous throughout the militaries of the World. Three makes have come to dominate the market, each offering a different design philosophy, Aimpoint, Eotech and Trijicon.

The Swedish manufacturer Aimpoint opted for an almost indestructible ‘tube’ design in a range of red dot sights that are parallax from 50 meters out making the firer’s head position all but irrelevant. Aimpoints come in many sizes featuring dots of different sizes for different uses. The US Army having standardized the Aimpoint CompM2 as its M68 is now purchasing the improved Model CompM4s. Note the small ‘s’ in the manuracturer’s designation. Aimpoints offer a somewhat narrower field of vision than holographic units when used with in-line night vision, but offer a far greater battery life – on some recent models at lower reticle brightnesses this can be years! Most Aimpoints are 1X powered, but a flip to side magnifier is available to boost them to 3X in an instant. This gives the operator the flexibility to engage long range targets should these appear in an otherwise CQB scenario. You can easily ‘co-witness’ back up iron sights on a rifle in the lower third of the sight picture, so you can still shoot accurately even if your Aimpoint is broken or its aiming window obscured. An alternative is to use offset back up iron sights or a see thru mount, though the latter can position the sight too high for correct cheek weld. Some aimpoints come with mounts, but a many alternatives are available from Aimpoint and aftermarket suppliers to allow the Aimpoint to be used in almost any conceivable configuration.

Eotech follow a different philosophy, bringing fighter-jet style HUD technology to individual weapon sighting. This eliminates parallax error and makes for very rapid target engagement. Multi-dot reticles are available to match the trajectory of the .223 Remington (5.56x45mm NATO) and .308 Winchester (7.62X51mm NATO) rounds. The Eotechs will display the entire reticle even if all but a small part of the aiming window is obscured or even if it is entirely shattered. The Eotechs don’t lend themselves to having their optics protected from the elements. A aftermarket set of flip up lens covers is available but it adds three ounces to the weight of the unit and doesn’t seal as well as the flip ups on the Aimpoints. Holographic Weapon Sights use up batteries far faster than Aimpoints, with battery lives measured in the hundreds rather than tens of thousands of hours – an automatic cut off is provided set to eight hours and user configurable to four. Eotechs are considered somewhat less robust than Aimpoints, but enough for demanding military operations. Eotechs have been adopted by USSOCOM, the 1st Stryker Brigade and the 3rd Infantry and 10th Mountain Divisions. US Special Forces Command demanded and got a 66 foot water proof depth – HWS have survived at this depth for days. Endorsement of their suitability for marine environment came from the Royal Navy which adopted an HWS for the defensive Dillon Miniguns mounted on its warshops and the auxiliaries of the RFA. Again a flip-to-side magnifier can be purchased – Aimpoint and Eotech magnifiers being effectively interchangeable. In some models NV compatibility and iron sight co-witnessing is assisted by a 7mm riser. These models typically feature ‘cantilevered’ front ends to clear the delta rings of AR15/M16 type rifles. Most Eotechs are night vision compatible – the most modern featuring brightness and NV buttons on the side of the unit to allow the magnifier or NV to be mounted right up to the back of the sight. Eotechs come with their own mounts to suit Weaver and Picatinny rails – depending on budget and desired amount of rigidity/detachability these can be bolt, thumb screw or ARMS type quick detachable throw levers. Many Eotechs are available in models to suit either CR123 or AA batteries offering longer life vs easier availability. The 557 with G.23FTS magnifier is a good example of an Eotech Holographic Weapon Sight.

Trijicon’s range of magnifying reflex sights covers a huge range of magnifications, objective lens sizes and reticle colours and patterns. ACOGs magnify and thus, like telescopic sights, can suffer from parralax, although this is of little or no consequence at the ranges at which these sights are actually used. Magnification enables far greater target identification and engagement ranges than would be possible with unitary power optic. It is possible so use an ACOG with both eyes open, but, for closer range engagements, some now boast either peep and post back-up iron sights and/or mount a small 1X red dot sight on top. Such a sight has recently been chosen by the British Army for their new L129A1 7.62mm designated marksman’s rifle. The USMC finally made the jump to universal issue of magnifying optics with two ACOGs tailored to the M4 carbine and M16A4 rifle respectively. The M4 carbine uses the AN/PVQ-31B. ACOGs do not require batteries (apart from some of the RMR top mounted back-up red dot sights), being fitted with a tritium light source with an additional fiberoptic light gathering device in the dual illuminated models. Trijicon make the basic sight suitable for M16 carrying handles, then add an adapter for either Picatinny or Weaver rails. This is available in screw or lever operated quick release versions.

Trijicon ACOG, Aimpoint and Eotech sights have replaced iron sights throughout the US armed forces, dramatically increasing combat effectieness and marksmanship scores. They are all excellent but expensive, so deciding which one to purchase is a non-trivial decision. Both can be boosted to 3 or 4X with flip to side or detachable magnifiers. You should consider the degree of detachability, whether you want to co-witness and whether you intend to use the sight with a close mounted magnifier or NV device. ACOGs offer magnification in a rugged compact package at the cost of some loss of close range capability in the higher magnification models. The CQB capability of the Eotech and Aimpoint can be added to the ACOG by opting for a model with its own back up iron or mounting a red dot sight mounted on top, or by going for the very low magnification models (down to 1.5X). If you’re looking to replace a higher powered scope the higher magnification ACOGs make excellent replacements. These higher magnification models really benefit from an RMR back up red dot sight for closer engagements.

These three manufacturers produce absolutely top notch optics that will take everything front line service in the military will throw at them. All are relied upon in life or death situations on a day to day basis.

For deals on the AN/PVQ-31B go to combatopticsreviews.com

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