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Review - Tokyo Marui M4 SOPMOD

Updated: Jun 20, 2021


History of Tokyo Marui Co. Ltd (株式会社東京マルイ)

Tokyo Marui (TM) is a Japanese company that in 1992 was the first to create the AEG (Airsoft Electric Gun). Over the past near 30 years the company has gone from strength to strength and

their brand is one of the best known in airsoft circles, not only for a high price but also for their quality and reliability.

For more info - visit Tokyo Marui website.

For more background info - visit Tokyo Marui Wikipedia.


Why TM and the M4 SOPMOD?

The M4 SOPMOD (Special Operations Peculiar Modification) enables operators to adapt the M4 rifle to a chosen environment utilising a number of attachments, namely; optics, firearm add-ons (shotgun and under barrel grenade launcher), laser aiming modules, suppressors etc. Whilst this adaptability is not unique to the SOPMOD, the rifle variant in itself is unique. The SOPMOD dates back in it's earliest form to 1989 and over the years progressively improved on itself to provide armed forces with an adaptable and reliable weapon.

The evolution of the SOPMOD can be split into 3 'blocks' as described below;

SOPMOD BLOCK I - (Plus Platform Mods and Phased Replacements)

USSOCOM (United States Special Operations Command) developed the Special Operations Peculiar Modification (SOPMOD) Block I kit for the M4 carbines. The kit as pictured below features; a Rail Interface System (RIS) handguard developed by Knight’s Armament Company (KAC), a short M203 grenade launcher, a KAC suppressor, a KAC rear flip-up sight, crane stock, an Insight Technologies AN/PEQ-2A visible laser/infrared designator, a Trijicon ACOG and Reflex sights, and a night vision sight. With a large number of readily available accessories, this adaptable rifle quickly came into use by US special forces.

SOPMOD BLOCK II - (New and Combined Capabilities)

The Block II kit was created to allow enhanced and newly developed accessories to be used alongside the standard M4 SOPMOD. The initial new accessories included; an Enhanced Grenade Launcher Module (EGLM), Enhanced Combat Optical Gunsight (ECOS), and Clip-On Night Vision Device (CNVD). This further enabled the rifle to be fielded in low light, and no light environments. Additionally the newly developed and adopted Block II kit would feature new upper receivers specifically designed for long range and close quarters battle (CQB) requirements. The long range upper was referred to as the Special Purpose Reciever (SPR), whilst the close quarters upper was referred to as the CQB Reciever (CQBR). Accessories included and utilised include many names such as Knight's Armament Company, Daniel Defense, Lewis Machine & Tools and the Atlantic Research Marketing Systems (ARMS).

SOPMOD BLOCK III - (Emerging Capabilities)

The true details surrounding the Block 3 requirements, systems and accessories relates to the continued R&D effort of US defence contractors and bodies to continue to enhance the US military's weapon systems. Ongoing development of lightweight equipment such as high performance Night Vision equipment, thermal imaging and laser identification modules continue to drive R&D whilst ensuring that operators are provide the best equipment currently available.

SOPMOD Evolves

In the early 2000's the Special Purpose Rifle (SPR) became the MK12. Shortly after, the CQB variant became the MK18 CQBR (Close Quarters Battle Rifle).

At the same time, through research and development, a new rifle was designed to meet US special forces requirements and the SCAR (Special Operations Forces Combat Assault Rifle) produced by the Belgian company 'FN Herstal' was admitted to US armouries. Two SCAR variants were designed, one to utilise 5.56 ammunition and the other to utilise 7.62 ammunition. Whilst take up by the military was minimal, it was adopted across the globe in both a military and a law enforcement role.

As with time; rifles, manufacturers and enemies etc evolve, however as the M4 SOPMOD is as adaptable, reliable and continues to be a cost effective platform it continues to be used by USSOCOM.


Product details

Herein lies the product description from the TM website;

  • Length: 803mm / 878mm (28.15″-38.19″), Folded / Total

  • Weight: 3370g (9.04lbs)

  • Inner Barrel: 445mm

  • Magazine Capacity: 82rd Mid-Capacity magazine.

  • Required TM New Gen. Mags

  • Muzzle Velocity: 300 FPS (approx)

  • Thread Direction: 14mm Negative

  • Gearbox: Ver 2 Full Metal, Proprietary

  • Motor: Long Type

  • Fire Modes: Semi/Full-Auto, Safety

  • Battery: Tokyo Marui SOPMOD 8.4v 1300mAh Battery (Not included)

  • Hopup: Yes, Adjustable


Packaging Exterior

The rifle as standard is encased in a card box 34 x 11.5 x 3.5 with a picture of the rifle on the outside and 3 of the 4 sides featuring the SOPMOD and TM logos. The 4th side has the rifle serial number and TM award sticker on it to help further prove that this is indeed a TM rifle.

Packaging Interior

Inside the box there are 4 main sections;

  • Rifle

  • Operators manual & documents

  • Magazine

  • Accessories box

Alongside the 4 sections, there are a couple of paragraphs detailing the rifle characteristics and information (including spelling mistakes).


The rifle fits into a rifle shaped mould cut into the thick cardboard, and it can be seen that the rifle is further held in place by 2 velcro straps, one looping over the rail and the other over the stock. When the box is closed, the rifle is further held in place by sections of large polystyrene glued to the box lid, that fit around the rifle, again adding security. Like the majority of TM products and their packaging, care has been shown to get the rifle from the factory to you without it dislodging from the inside and potentially causing any damage.

Operators manual

The operators manual sits on the left hand side of the box under the barrel. The main document is the 'Operator's Manual' detailing in both Japanese and English the standard of use, hop adjustment, safety etc. The second document is a 'Supplementary explanation' which provides a 4 page in detail description of the SOPMOD battery. Also included underneath this section are a number of documents within a plastic wallet and are all in Japanese relating to personal safety and use of the rifle around others. The wallet also contains a set of standard paper shooting targets to test the rifle on.


This section contains 1 magazine, again fitting tightly into a cut out mould in the thick card base layer. To the right hand side of the magazine is some printed information relating to the rifles characteristics.

Accessories box

This small removable box contains;

  • Battery Connector

  • Bag of non-descript BBs labelled 'for testing'

  • Protective cap (for the flash hider)

  • Hex wrench (allen key)


Rifle Internals

The rifle as standard (and with all TMs) is out of the box a milsim/skirm ready rifle. The only upgrade at this time to the M4 SOPMOD was the replacement of the standard barrel with a Laylax (Prometheus) 6.03mm EG inner barrel at 363mm. I wanted to run a suppressor and therefore a longer inner barrel that protruded from the end of the outer barrel but was still protected by an attached suppressor seemed like a good choice.


Rifle Externals

The rifle body is cast from high grade aluminium as is the majority of the external parts. Altogether as stock, the M4 weighs in at 3.4kg (7.67lb). The real steel version weighs in slightly heavier at 3.51kg. The receivers are both anodized matt black and thus offer protection against slight scratches. Markings have been stamped into the metal receivers rather than stamped on.


The rifle comes with a short quad RIS (Rail Integrated System) rail. The RIS rail variant, simply means that the rail is attached to both the delta ring and the front sight post. Being quad rails and having 16 teeth per rail, this allows the operator to attach any number of accessories to make the rifle suitable for any operational environment. Each rail measures 17cm (6.69"), enough for a PEQ on top, foregrip underneath and a torch on the side. The rail when dismantled breaks into two parts, the 'upper' and the 'lower'. The upper rail constitutes 3 of the rails (top, left and right), whilst the lower (under barrel) is one rail. Each of the rails is at every 2nd groove marked with position markers ie on the top rail the 2nd groove starts at and increments by two ie T14, T16, T18 etc.


The body of the rifle is made up of two parts called 'receivers', the 'upper receiver' and the 'lower receiver'. Both upper and lower on both sides are marked with near real steel markings, safety, single, auto firing methods and TM markings etc. The receivers are both made of high grade aluminium.

On the left hand side of the lower receiver between the safety and the bolt release catch is stamped;




On the left hand side of the lower receiver on the magwell is stamped;



CAL. 5.56 MM.


On the right hand side of the lower receiver between the magazine release catch and the safety is stamped;




Unlike the TM HK416 the upper and lower receivers do not have serial numbers stamped which does take away from some of the realism, a small detail missed. Instead, the 'W406734' stamp on the magwell is an attempt at recreating a rifles unique issued serial number. The body of the rifle is rigid and it's manufactured quality provides a decent weight without it being too overbearing. The fitted charging handle provided is the standard M4 charging handle, but like most TM products, can be changed if required.


The stock attached to the rifle is a standard 6 point adjustable polymer crane stock. The stock is larger than a standard Magpul CTR (Compact/Type Restricted) stock, and is designed to house the TM standard SOPMOD nickel battery. The stock does allow a belt style sling to be fitted acting as a rear attachment point. This crane stock can easily be removed and replaced with the Magpul CTR stock if required. Recommendation is to ditch the TM SOPMOD style battery and replace with a 7.4v lipo battery.


The standard anodized black metal flash hider is screwed onto the outer barrel thread as seen in the second picture, but there is no miniature hex screw to firmly attach the flash hider to the outer barrel. The flash hider is a TM M4 design and is fitted CCW (Counter Clock Wise). Between the flash hider and the outer barrel sits a 2.5mm thick metal ring as shown in the 3rd and 4th images below, that allows the flash hider or a suppressor to be tightened to the outer barrel without causing damage and does provide a break between outer barrel and accessory when fitted.

The front post sight is clamped to the outer barrel and can be removed with some modification, by removing the two loaded pins as seen at the base of the front post in the 1st picture. When stock from the box, included and attached is a removable LMT (Lewis Machine & Tool) Rear Sight although it's without trademarks. The LMT allows the operator to make adjustments as per the real steel version using the windage dials to move the aiming reticule left and right or up and down if required. The LMT is fitted using the standard rail clamp.

The suppressor fitted is a SOCOM 556 R2 Surefire 5.56 QD reproduction (purchased separately). This is the main suppressor that I transfer between rifles and it's a near perfect imitation of the actual Surefire SOCOM 556 R2 suppressor. This is also the standard suppressor used by SEAL Teams' Bravo on their HK 416 rifles and a number of other rifles in their armoury.

The M4 SOPMOD uses proprietary TM magazines designed for use in the recoil system that provide added realism of the weapon stopping when the magazine is empty. The magazine (far left) that came with the M4 houses 82bbs as a mid cap. The bottom of the magazine is stamped with 'COLT AR-15 CAL 5.56 MM MADE IN JAPAN MARUI CO. LTD'. This magazine and stamping is identical to that of the magazine supplied with the TM 416 and thus is inter-changeable.


Firing range

The rifle was taken to the range to provide an accurate review of the firing capabilities of the M4 SOPMOD and what the stock internals (bar new inner barrel) enable the rifle to achieve. The weather on the range;

  • Precipitation: 23%

  • Humidity: 86%

  • Wind: 10mph

  • Visibility: Clear

  • Time: 20:00

  • Nuprol RZR bbs were used solely for all weights testing.

  • An XCortech X3200 MK3 chrono was used.

Semi Auto

The below table includes results for semi auto only using both FPS / Joules. It can be seen that the FPS flux differs across 10 shots minimally for all weights. From the results the SOPMOD performed best with the least FPS flux using .4s.


The average 10mph wind seen on the range, blew from Northwest to Northeast across the targets with worst effect approx 60% of the way downrange, therefore the SOPMOD was not able to be shot in a stable weather environment. Any results returned from the range in these conditions would not be a true reflection of the SOPMODs capabilities as a base measurement. This test will be retaken soon and blog updated.


Thoughts and opinion

As I have said in the TM HK416 review, Tokyo Marui have a fantastic reputation built over many years. They keep delivering quality products with high levels of detail and customer care that draw people in. Cost vs reliability is again a factor. The rifle overall is an effective addition to the armoury, especially when used in the DMR role. It's ability to share TM magazines with my 416 is beneficial and there is enough real estate to add most attachments to it. Keeping it light with a 4 x 90 scope, lightweight bipod and a PEQ box mean that it's ready for most situations. Again if you want a skirm/milsim ready rifle out of the box, this one is for you.

Yes the TM M4 SOPMOD costs more than other manufacturers, yes it has recoil and yes it is an effective weapon. I do recommend that if you want something slightly different from the standard 'short / mid' M4 but in keeping with Western forces armouries, I would encourage you to give the SOPMOD a go. I've found it to be a reliable and long reaching rifle and will certainly be using it into the near future alongside my 416.


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Final Note

I am not paid for my blogs by the manufacturers or companies that I purchase my items from. I am not offered freebies to promote a product. These blogs are purely written from my own experience in truth to help advise and inform others who may wish to purchase the items or understand more about them. If I am sent a freebie to review this will be stated at the beginning to make you aware.

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