The 14 Best M4 Scopes & Optics in 2021

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The military-issue M4 and M4A1 carbines have a lot in common with typical civilian AR-15 carbines. Other than the fire selector (M4s have a full-auto option, AR-15s are semi-auto only) and the barrel length, the two platforms are virtually identical, allowing them to use the same scopes and optics.

Whether you need an optic for hunting, target shooting, competition, close-quarters, or home defense, read on to learn about the best M4 scopes and optics you can buy today.

Best M4 Scopes & Optics

1. Aimpoint Micro T-2

aimpoint micro t-2

The Aimpoint Micro T-2 is one of the most popular red dot sights for AR-15s, M4s, and equivalent platforms.

The main appeal of the Micro T-2 is its form factor. It is an ultra-compact red dot sight, only 2.7” long and weighing no more than 3.3 oz., with the capabilities of a much larger product: up to 50,000 hours of autonomy on a single CR2032 battery.

When looking through the T-2, you will find a crisp, sharp, red center dot with a 2 MOA diameter. In addition, the top-quality, multi-coated, anti-reflex glass retains up to 70% of ambient light without discoloration, allowing you to see and engage targets with utmost clarity.

Specifications:

  • Optic type: Red dot sight
  • Magnification: 1x
  • Objective lens diameter: 18mm
  • Eye relief: Unlimited
  • Reticle system: Red dot, 2 MOA
  • Illumination: Yes, 8 daylight settings + 4 night-vision settings, requires 1 CR2032 battery
  • Length: 2.7”
  • Weight: 3.3 oz.
  • MSRP: $782 to $910 depending on mount options

2. EOTech EXPS3-0

eotech exps3-0

The EXPS3-0 by EOTech is one of the premier sight choices for civilian shooters, law enforcement officers, and warfighters equipped with the AR-15 or M4 platform worldwide.

Part of the EXPS family of compact holographic weapon sights, the EXPS3 is the latest iteration, with redesigned controls. The night vision switch and brightness adjustment switches are now on the left side instead of the rear end, letting users make changes on the fly with more natural motions.

The EXPS3-0 model features the classic EOTech One Dot reticle, featuring a close-quarters 68 MOA ring and a 1 MOA center dot, accurate at 50 and 200 yards with 5.56mm 62-grain ammunition.

Specifications:

  • Optic type: Holographic weapon sight
  • Magnification: 1x
  • Objective window size: 30.5mm x 21.6mm
  • Eye relief: Unlimited
  • Reticle system: EOTech One Dot
  • Illumination: Yes, 20 daylight settings, requires 1 CR123 battery
  • Length: 3.5”
  • Weight: 11.2 oz.
  • MSRP: $725

3. Vortex Crossfire II 1×22 Red Dot Sight

vortex crossfire ii 1x22 red dot sight

The Crossfire II red dot sight is a compact, lightweight optic, suitable for any AR-15 or M4 close-quarters or home defense build. The center dot is just what you’d expect from a quality red dot sight: bright red, 2 MOA, sharp and crisp, easy to acquire in CQB situations.

This sight features 11 brightness setting levels, powered by a single CR2032 battery included in the box. You can expect a battery life of about 50,000 hours when continuously powered on brightness setting 6.

The box also includes a rubber cover, a T-10 Torx wrench, and a stylish, skeletonized 1/3 co-witness mount, making the Crossfire II ready for installation on your carbine’s top rail right out of the box.

Specifications:

  • Optic type: Red dot sight
  • Magnification: 1x
  • Objective lens diameter: 22mm
  • Eye relief: Unlimited
  • Reticle system: Red dot, 2 MOA
  • Illumination: Yes, 11 settings, requires 1 CR2032 battery
  • Length: 2.5”
  • Weight: 5.2 oz.
  • MSRP: $219.99

4. Trijicon MRO

trijicon mro

The Trijicon Miniature Rifle Optic (MRO) provides shooters with a compact, lightweight red dot sight suitable for mounting on rifles, carbines, submachine guns, shotguns, and many other platforms.

The MRO employs a capless design, using sub-flush adjusting turrets instead of traditional caps. This design significantly reduces the risks of snagging or losing zero on the field.

In addition, the MRO also features intuitive, fully ambidextrous brightness settings, top-quality lenses with the best multi-coatings, and a long-lasting battery, averaging at 5 years for the red dot model and 1 year for the green dot version.

Specifications:

  • Optic type: Red dot sight
  • Magnification: 1x
  • Objective lens diameter: 25mm
  • Eye relief: Unlimited
  • Reticle system: Red or green dot, 2 MOA
  • Illumination: Yes, 8 settings, requires 1 CR2032 battery
  • Length: 2.6”
  • Weight: 4.1 oz.
  • MSRP: $579 to $749 depending on options

5. Aimpoint CompM5

aimpoint compm5

The Aimpoint CompM5 is the latest iteration in the Comp series of combat red dot sights, part of the same family as the US armed forces’ CompM2 (M68 CCO), frequently seen on military M4, M4A1, and M16 platforms.

As a modernized version of the classic CCO, the CompM5 offers the features you’d expect from an Aimpoint: a crisp 2 MOA red dot, an anodized aircraft-grade aluminum construction, fully multi-coated lenses offering up to 70% light transmission, and Aimpoint’s unmatched build quality.

Unlike many optics on the market, the CompM5 requires a AAA battery instead of a CR2032, lasting up to 50,000 hours. In addition, the sight is NVD compatible and supports Aimpoint magnifiers for reaching targets at extended distances.

Specifications:

  • Optic type: Red dot sight
  • Magnification: 1x
  • Objective lens diameter: 18mm
  • Eye relief: Unlimited
  • Reticle system: Red dot, 2 MOA
  • Illumination: Yes, 6 daylight settings + 4 night-vision settings, requires 1 AAA battery
  • Length: 3.4”
  • Weight: 8.4 oz.
  • MSRP: $828 to $991 depending on mount options

6. SIG Sauer Romeo-MSR

sig sauer romeo-msr

The SIG Sauer Romeo-MSR is an affordable red dot sight primarily intended for modern sporting rifles, offering features and build quality equivalent with much higher-priced optics, including SIG Sauer’s Romeo4 and Romeo5 sights.

Powered by a single CR1632 battery, the Romeo-MSR provides the shooter with a 2 MOA red or green dot (depending on the model) and 12 illumination settings: 1 and 2 are night-vision modes, 3 to 5 are low-light modes, and 6-12 are daylight-bright modes.

You can order the sight as a standalone unit or with a SIG skeletonized mount for quick installation on your AR’s top rail. Best of all, there is no price or autonomy difference between the red and green dot models; choose the dot color you find most useful, install on your rifle, and you’re ready to go.

Specifications:

  • Optic type: Red dot sight
  • Magnification: 1x
  • Objective lens diameter: 20mm
  • Eye relief: Unlimited
  • Reticle system: Red or green dot, 2 MOA
  • Illumination: Yes, 10 daylight settings + 2 night-vision settings, requires 1 CR1632 battery
  • Length: 3.1”
  • Weight: 4.9 oz.
  • MSRP: $159.99

7. EOTech EXPS2-2A

eotech exps2-2a

The EOTech EXPS2-0A is one of the most compact holographic sights on the market today, thanks to its advanced design and its ultra-short battery compartment. This unit requires only a single CR123 battery for power, providing the shooter with 1,000 continuous hours of operation.

Like all other EOTech holographic sights, the EXPS2-0A features an auto-shutdown system, automatically turning the reticle system off after 8 hours of inactivity. Keep in mind that the 8-hour timer resets every time you change the brightness settings.

Unlike a traditional red dot sight, the EXPS2-2A provides you with a complete reticle system consisting of a circle and two dots.

The center dot is 1 MOA in diameter and is accurate at 50 and 200 yards (with standard .223 / 5.56mm 62-grain ammunition). The lower dot is also 1 MOA in diameter, serving as your 500-yard aiming point. Surrounding both dots is a 68 MOA circle, intended for use in close-quarters combat.

Specifications:

  • Optic type: Holographic weapon sight
  • Magnification: 1x
  • Objective window size: 30.5mm x 21.6mm
  • Eye relief: Unlimited
  • Reticle system: EOTech Two Dot
  • Illumination: Yes, 20 daylight settings, requires 1 CR123 battery
  • Length: 3.8”
  • Weight: 11.2 oz.
  • MSRP: $619

8. EOTech 512

eotech 512

The EOTech 512 is the most popular 500-series sight and perhaps the most famous EOTech product overall, having been on the market for over 20 years. It is a classic choice for AR-15 and M4 platforms.

The long battery compartment accepts 2 AA batteries, available virtually everywhere worldwide. They provide the EOTech 512 with an average autonomy of 2,200 to 2,500 hours, depending on the battery used and the settings employed.

With 20 daylight settings, the EOTech 512 can easily be adapted to any light conditions from dawn until dusk. It also features the classic EOTech One Dot reticle, with a central 1 MOA red dot accurate at 50/200 yards (with standard .223/5.56mm 62-grain ammunition) and a 68 MOA circle ideal for close-quarters engagements.

Specifications:

  • Optic type: Holographic weapon sight
  • Magnification: 1x
  • Objective window size: 30.5mm x 21.6mm
  • Eye relief: Unlimited
  • Reticle system: EOTech One Dot
  • Illumination: Yes, 20 daylight settings, requires 2 AA batteries
  • Length: 5.6”
  • Weight: 11.5 oz.
  • MSRP: $499

9. SIG Sauer TANGO4 1-4x24mm

sig sauer tango4 1-4x24mm

The SIG Sauer TANGO4 1-4x24mm is the LPVO model in SIG’s TANGO4 line of hunting and competition riflescopes, ideally suited for modern 5.56mm and .308 carbines.

This version of the TANGO4 offers everything you’d expect from a compact, close- to medium-range LPVO: a magnification range of 1x to 4x, a 24mm objective lens, multi-coated glass with low dispersion, and a range of practical BDC reticle options, all projected on the first focal plane.

The TANGO4 1-4x24mm accepts standard 30mm scope rings and features ideal dimensions for mounting on the top rail of a typical AR-15 or M4 upper receiver. It’s the perfect choice if you’re looking for your first LPVO.

Specifications:

  • Optic type: Low power variable optic (LPVO)
  • Magnification: 1x – 4x
  • Objective lens diameter: 24mm
  • Eye relief: 3.3”
  • Reticle system: 3 options
    • 5.56/7.62 horseshoe dot, .300 BLK horseshoe dot, or MRAD Milling
  • Focal plane: First (all reticles)
  • Illumination: Yes, 8 daylight settings + 2 night-vision settings, requires 1 CR2032 battery
  • Length: 10”
  • Weight: 15.9 oz.
  • MSRP: $499

10. Vortex Viper PST Gen II 1-6x24mm

vortex viper pst gen ii 1-6x24mm

The 1-6x24mm version of the popular Vortex Viper PST Gen II line of riflescopes competes in the LPVO segment, offering a selection of features attractive to hunters, competition shooters, and any civilian looking for versatility and accuracy from 0 to 600 yards.

Inside the 30mm aluminum scope tube, you will find multi-coated glass with extra-low dispersion, providing maximum light transmission, true color display, and near-perfect visibility under daylight conditions.

The Viper PST Gen II 1-6x24mm uses the Vortex VMR-2 reticle system, available in two variants: the VMR-2 MRAD with milliradian hash marks, and the VMR-2 MOA, with MOA bullet drop compensation marks. Both reticle systems are on the second focal plane.

Specifications:

  • Optic type: Low power variable optic (LPVO)
  • Magnification: 1x – 6x
  • Objective lens diameter: 24mm
  • Eye relief: 3.8”
  • Reticle system: 2 options
    • Vortex VMR-2 MRAD or Vortex VMR-2 MPA
  • Focal plane: Second (all reticles)
  • Illumination: Yes, 10 daylight settings, requires 1 CR2032 battery
  • Length: 10.9”
  • Weight: 22.7 oz.
  • MSRP: $899.99

11. EOTech Vudu 1-6x24mm FFP

eotech vudu 1-6x24mm ffp

EOTech first entered the traditional riflescope market with the Vudu, a line of LPVOs explicitly designed for the AR-15, M4, and equivalent modern sporting rifles and carbines.

This model features premium-quality Japanese-made glass, easily adjustable turrets, and a highly versatile magnification range of 1x to 6x.

Three different reticle systems are available: the SR1 MRAD with milliradian marks and two BDC reticles; the SR2 for .223 platforms and the SR3 for .308 rifles.

The Vudu bridges the gap between holographic sights and riflescopes, offering true 1x magnification and red dot-like performance at the lowest magnification setting while allowing the shooter to accurately engage targets at extended distances (500 to 800 yards, depending on caliber).

Specifications:

  • Optic type: Low power variable optic (LPVO)
  • Magnification: 1x – 6x
  • Objective lens diameter: 24mm
  • Eye relief: 3.5”
  • Reticle system: 3 options
    • EOTech SR1 MRAD, EOTech SR2 5.56 BDC, or EOTech SR3 7.62 BDC
  • Focal plane: First (all reticles)
  • Illumination: Yes, 10 daylight settings, requires 1 CR2032 battery
  • Length: 10.63”
  • Weight: 19.75 oz.
  • MSRP: $1,399

12. Trijicon TA31-C ACOG 4x32mm

trijicon ta31-c acog 4x32mm

The Advanced Combat Optical Gunsight (ACOG) is Trijicon’s most well-known sight, first adopted by the US armed forces in 1987 and extensively utilized on M4 carbines, M16 rifles, and various other military weapons platforms.

The ACOG is a fixed-power 4x scope, featuring the well-known TA31 reticle system (with 5.56mm BDC marks accurate to 600 meters) and the TA51 mount, ready for mounting on your M4 or AR-15’s top rail.

Compact, lightweight, and battle-proven, the ACOG withstands the recoil impulses of any platform, from .22 LR rifles to .50 BMG heavy machine guns. The dual illumination system combines tritium and fiber optic to provide a bright aiming reticle under all lighting conditions.

Specifications:

  • Optic type: Fixed-power scope
  • Magnification: 4x
  • Objective lens diameter: 32mm
  • Eye relief: 1.5”
  • Reticle system: Trijicon TA31
  • Focal plane: Second
  • Illumination: Yes, 6 daylight settings, requires 1 AA battery
  • Length: 7.3”
  • Weight: 15.1 oz.
  • MSRP: $1,605

13. Leupold VX-Freedom Scout 1.5-4x28mm

leupold vx-freedom scout 1.5-4x28mm

The Leupold VX-Freedom Scout is one of the best riflescopes for shooters looking to turn their AR-15 into a hunting or scout rifle platform.

Although dimensionally similar to LPVOs, this scope’s minimum magnification setting is 1.5x, making it a traditional variable-power optic instead. The Twilight Light Management coatings protecting the glass ensure maximum light transmission even in low-light environments.

With a 28mm objective lens, a traditional duplex reticle, and Leupold’s exceptional Punisher-tested build quality, the VX-Freedom Scout is a simple, highly durable optic, ideally suited for intense daily use.

Specifications:

  • Optic type: Variable-power scope
  • Magnification: 1.5x – 4x
  • Objective lens diameter: 28mm
  • Eye relief: 1.5”
  • Reticle system: Leupold Duplex
  • Focal plane: Second
  • Illumination: No
  • Length: 11.2”
  • Weight: 9.6 oz.
  • MSRP: $349.99

14. Bushnell AR 3-9x40mm

bushnell ar 3-9x40mm

The Bushnell AR 3-9x40mm is the ideal riflescope for the shooter using their AR-15 as a long-distance target shooting or hunting platform.

It is a traditional variable-power scope, featuring a versatile magnification range (3x to 9x), a wide field of view (40mm objective lens), and fully multi-coated, fog-proof lenses.

The Bushnell AR comes with a power throw lever and the Drop Zone-223 BDC reticle system, intended explicitly for use with .223 / 5.56mm 62-grain projectiles. At the maximum magnification setting, the BDC marks are accurate at up to 500 yards.

Specifications:

  • Optic type: Variable-power scope
  • Magnification: 3x – 9x
  • Objective lens diameter: 40mm
  • Eye relief: 3.5”
  • Reticle system: Drop Zone-223
  • Focal plane: Second
  • Illumination: No
  • Length: 12”
  • Weight: 19 oz.
  • MSRP: $159.99

The Verdict

Choosing the right optic for your intended applications is critical if you want to get maximum effectiveness out of your rifle.

Fixed-power scopes are ideal for medium-range applications, whereas traditional variable-power optics are best suited for hunting or long-range target shooting.

For home defense and close-quarters combat applications, use one of the red dot or holographic sights. If you need a do-it-all platform suitable for every situation, choose one of the LPVOs.

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