the M21, a reflex sight we all know and recognize from photos of IDF rifles, has finally hit the airsoft market at an affordable price and is a good quality replica. Rather than drop a few hundred dollars on a surplus or brand new M21, you can now purchase a reproduction model for roughly $80 USD!

So before we get to the meat of this review and take an in depth look at the M21, let’s talk about some real world history!

Above image: the M21 equipped on the Tavor 21 rifle. Lower image: a soldier in the  IDF Caracal Battalion (Hebrew: גדוד קרקל‎‎) 

History of the M21

The M21 was designed in close collaboration with IDF special forces in the mid ’90s. The first of its kind was designed for close quarters combat. The company Meprolight, founded in 1990, is responsible for the M21 becoming the first successful optic to hit the market. It is standard issue across the board for the IDF and is now replacing their newer model: the M5. However, surpluses of  M21’s still float around in the ranks. The M21 replaced the pre-built-in optic on the Tar21, known as the MARS Red Dot Sight, and is also standard issue on the X95s.

The M21 closely resembles the Trijicon reflex sight, only larger and more distinct with the protective cage housing the front of the optic’s fiber optic. The IDF purchased a few of the Trijicon reflex optics before developing a home grown version. Both optics were produced around the same time, however the Trijicon never entered formal military service in the US military or the IDF.

The M21 features a fiber optic powered reticle during the day and tritium during the night, allowing the sight to seamlessly transition from day-to-night operations (although the optic is technically always on). The M21 is a 30mm sight, allowing both eyes to be open during engagements. The window is large, clear, and doesn’t impede the shooter’s view. The M21 is durable as all sin, and able to operate in all conditions.

Above: the repro-M21s on my own ARES Tavors ( All the IDF feels ).

AIM M21 Relex sight

As excited as I was at the time, I purchased two of these optics off of for $260 CAD including shipping (weak Canadian dollar). Both optics came well packaged in a solid cardboard box with the company name and logo on it.

The box contained:

  1. One Allen Key
  2. Micro-fibre cloth
  3. Kill-flash
  4. Rubber protective cover
  5. M21 reflex sight

The AIM M21 is a solid built reproduction featuring NO trademarks (legal reasons), a red fiber optic cage, and red refraction coating on the front of the lens. To my suprise, the main reticle,  is a “bull’s eye” over a 4.3 MOA dot — a nice touch if I may add. The right side of the optic features quick throw arms for quick and easy removal, and the left has two nuts which are adjustable. The top of the optic has your elevation adjustment point to the bottom right corner and the windage adjustment on the lower right side corner of the optic. Both adjustment screws “click” to indicate movement and are very sensitive — a HUGE plus for a repro.

The power source for this optic are two small batteries housed in the back right hand side of the M21, with a light sensor to the front lower left side of the optic. The battery compartment is connected by a fiber optic, which allows the sight to feature “autogating”. For an airsoft optic this is a big plus because it allows the optic to self-regulate the brightness level of the reticle vs you having to adjust accordingly using buttons. This allows for better combat use and less time toying with your gear. However, “washout” becomes an issue during urban combat or day-to-night operations. This repro will NOT function during the night due to the light sensor and no direct on-off switch. The battery compartment is accessible by removing the bottom rail plate, allowing you to change out the batteries when they run dry.

Above: the base “power” source for the (real) M21 on the right, and the (repro) on the left. Note the differences: the repro has the small battery compartment and the real has a tritium fiber optic. 


The AIM M21 is an excellent reproduction with a robust build, fantastic packaging, sharp reticle, clear glass, and quality price, which  make for a great purchase. I rate the optic a 4 out of 5, due to the washout issue and beacause the airsoft version is a true daytime optic. However, if you are looking for an affordable Israeli style optic for a project or just a solid reflex, you can’t go wrong with the AIM M21 reflex sight.

— Schoolboy out