WE M4A1 Open Bolt GBBR; V3 System

WE
Code:
£479.99
  • Full metal construction
  • 6.04mm Tightbore inner barrel
  • V3 System - Steel parts, redesigned internals

If you're a realism seeker looking for the next step up from an AEG, the WE M4A1 Open Bolt GBBR; V3 System has your name on it! A considerable improvement over the previous WE Open Bolt M4 GBBR, the V3 improves reliability with choice steel internals, reinforcement in key places and a full internal redesign resulting in better rapid fire performance and long-term durability.

The most notable redesigns are its steel valve knocker and steel bolt catch contact surface, solving known issues with WE's previous designs and avoiding the immediate need for upgrades or bodge jobs. The trigger group has also been considerably reinforced, but the inner barrel and HOP-up bucking are still GBB/VSR spec, giving you access to some of the best upgrade parts in the business if you want to improve accuracy and range. The stock inner barrel is also now a 6.04mm tightbore, replacing the 6.08mm standard bore barrel of the previous version.

If you prioritise realism and like to work hard in-game like the real warriors do, the WE M4A1 Open Bolt GBBR; V3 System should be on your shopping list. With realistic 30-round magazines, violent recoil and a manual of arms almost identical to the real M4A1, this is a primary for the pros!

Full description

Description

If you're getting bored of AEGs and want more recoil and realism, the WE M4A1 Open Bolt GBBR; V3 System should be right up your street! A detailed full metal M4A1 replica, the M4A1 V3 represents a significant redesign of WE's original M4A1 Open Bolt GBBR, resulting in better long-term reliability, improved consistency and better gas efficiency during rapid strings of fire.

Improvements in the V3 include a redesigned bolt catch with a steel contact surface which locks on a large cutout in the redesigned bolt carrier, solving the previous version's issues with locking back reliably in the long term. The rubber parts have been upgraded with a cold-resistant formula, resulting in better gas efficiency and improved rapid fire performance. All the trigger components have been redesigned and reinforced, and the valve knocker is now steel, solving another common long-term weakness in the original WE M4 Open Bolt GBBR.

These changes, unfortunately, mean aftermarket upgrades from the previous version are not compatible with the V3, though we expect RA Tech, Dynamic Precision and other Taiwanese upgrade manufacturers will soon start catering to this new system. The inner barrel and HOP-up unit are still VSR/GBB compatible, meaning you have access to the best of the best when it comes to accuracy and range enhancements.

Starting at the front, we can find a birdcage flash hider made from steel mounted to the 14mm CCW male threads at the tip of the 14.5-inch outer barrel. The outer barrel profile perfectly matches the real steel "Heavy" M4A1 barrel profile, including its reinforced sections and M203 mount cutout. While the birdcage is the perfect device for an M4A1 replica and is flawlessly machined, it can be replaced with any 14mm CCW-compatible tracer unit or suppressor. If you're going for the M4A1 SOPMOD Block 1 look, we recommend the Big Dragon Knights Type QD Silencer.

Next up, we come to the M4A1 style triangular front sight post, which is constructed from steel and houses the front sight and mock bayonet lug. The bayonet lug is an important part of the realistic M4A1 shape and can also be used to mount a Dummy Bayonet, though ask the marshals before using your dummy bayonet in-game, particularly fixed to your primary! The front sight itself is adjustable for elevation using an M4/AR-15 front sight adjustment tool, and for less precise work up close, it can be used as an index point for rapid aiming when there is no time to align the sights.

Mounted to the bottom of the front sight assembly, we have our first sling point, which is a standard steel footman loop compatible with a wide variety of sling types. This can be paired with any of the 3 rear sling mounting options to fit a two-point rifle sling to take the burden off your arms or allow for easy transitions to a sidearm. The perk of a relatively old-school design is that all the sling points are built in, meaning no extra adapters are needed!

Following the front sight, we come to the handguard assembly, which is constructed from a combination of alloy, steel and high-density polymer. The handguards themselves are the standard 2-piece M4A1 type with a ribbed surface to enhance wet-weather handling. The handguards are held in place using a steel handguard cap at the front, and an alloy delta ring at the rear. The handguards are made in two parts, allowing you to remove the lower handguard and mount an M203 grenade launcher to the barrel for some extra firepower.

The modularity of the M4 platform is easily its best feature, and it is no surprise that it gained the nickname "Barbie for men" following its "SOPMOD Block 1" upgrade. This modularity also extends to exchanging external parts, and with an M4/AR-15 armourers' wrench, you can change the entire front set of the M4A1 and make it look like practically any M4/AR-15 variant out there. Even if you don't have an armourers' wrench, the delta ring front end is compatible with any 7-inch drop-in rail system or handguard set for delta rings, so if you want to change up the looks of your M4A1, you'll be happy to learn that it can be done without a single tool!

Moving rearward, we reach the receiver, which is a familiar M4/AR-15 layout with a few enhanced parts for a hint of modernity. The receiver is constructed from alloy with a matt black finish and is equipped with a stamped steel dust cover in the classic M4A1 style. At the rear of the receiver, we are also treated to a steel QD sling plate, allowing you to add a QD sling swivel and make use of a single-point sling.

The fire selector is located on the left side of the AEG and sits directly above the pistol grip to provide fast and easy access for right-handed shooters. The fire selector has a 90-degree throw between modes, making it quick to operate but not too easy to accidentally knock it and end up in the wrong fire mode. Each fire mode is indicated with standard M4A1 markings reading "SAFE - SEMI - AUTO" in nice, crisp engravings. Like many GBBRs, the WE M4A1 V3 cannot be put into the "SAFE" mode without first being cocked, just like a real M4!

The bolt catch is right where we would expect; on the left side of the receiver, smack bang in the centre. On a GBBR, the bolt catch works exactly like the real thing, allowing you to quickly return the bolt carrier to battery after a reload and avoid using the charging handle. One of the main improvements of the V3 system is its redesigned steel bolt catch contact surface, providing a more reliable lock-back when your mag is empty, especially in the long term.

The magazine release is on the right side of the magazine well and is ideally positioned to be pressed with the trigger finger from a firing grip for right-handed users. Left-handed users can use their support hand thumb to press the release, and this can be done quite fast with a little practice. The surface of the mag release is textured to provide the necessary gripping qualities, and is protected from accidental presses by the "magwell fence", a raised protrusion in the receiver which stops the mag release from catching on your gear as you move.

The HOP-up unit of the WE M4A1 V3 is located inside the upper receiver, similarly positioned to the previous WE Open Bolt M4A1. To access it, first put the fire selector switch into the "SEMI" position, then rack the charging handle. With the internal hammer cocked, push the rear receiver pin through from the left side. With this done, hinge the receiver open about the front pin and remove the bolt carrier, then the charging handle. The Grub key adjuster is just above the chamber, and thoughtfully, the correct Allen key to adjust it is included in the box.

The pistol grip is the legendary "A2" type, first seen on the M16A2 and common on military builds. The grip boasts textured panels on each side for improved traction and a finger ridge to help support and control the front end of the Shorty when held in the "high ready" position. The pistol grip is compatible with real steel and GBBR aftermarket replacements, should you have a preferred grip for your build.

Following the receiver, we reach the AR buffer tube, which is a common part found on the vast majority of M4/AR-15 AEGs and GBBRs. This buffer tube is constructed from alloy and provides 6 positions of adjustment for the pre-installed L.E. style stock, enough to suit any body type or loadout. The buffer tube system allows you to swap your stock out for any aftermarket M4/AR-15 stock simply and quickly, so if you get tired of the looks of the M4A1 in the future, swapping out the stock can style it up!

Inside, WE has learned a lot when it comes to GBBR internal design, as evidenced in this updated V3 system. As mentioned, the bolt catch has been redesigned to lock on a wider part of the bolt carrier and the contact surface is now steel, meaning more reliable lock-back in the long term. The rubber components have also been upgraded for cold resistance, reducing the negative effects of "cool-down" under rapid fire for improved accuracy and consistency downrange. The valve knocker is also made from steel, addressing a known weak point in the previous WE M4 GBBR system, and the trigger components and bolt carrier have also been reinforced in key places to extend lifespan.

Compatibility-wise, a lot has changed in the V3 M4, meaning aftermarket upgrades for the previous versions of WE's M4 GBBR are no longer compatible, nor are the previous generation of WE M4 GBBR magazines. The new magazine still features the "dry fire" mode, which can be activated by holding the tab at the left rear of the magazine down and sliding the textured button back to lock it in place. The inner barrel and HOP-up bucking are still VSR/GBB spec, giving you plenty of options for accuracy and range upgrades, and the stock inner barrel is now a 6.04mm tightbore example, providing better accuracy with good quality ammo and a slight FPS boost compared to the previous version's standard bore 6.08mm barrel.

If you want to get into the hard-recoiling GBBR life, the WE M4A1 Open Bolt GBBR; V3 System is a sure hit. With realism, recoil and immersion in equal measure with improved long-term reliability and durability, WE has finally perfected its popular GBBR platform!

Features

  • Full metal construction
  • Gas Blowback Rifle - Heavy recoil, realistic handling, low-cap mags - A rifle for the pros!
  • 6.04mm Tightbore inner barrel - Superb accuracy potential
  • V3 Internal System - Steel valve knocker & bolt catch, redesigned for reliability
  • 14mm CCW Male threaded outer barrel - Tracer/suppressor ready
  • "Heavy" profile M4A1 barrel - Complete with M203 cutout and reinforced sections
  • M4A1 Triangular front sight post/gas block - Iconic M4A1 styling
  • High-density polymer M4A1 ribbed handguards - Comfortable and lightweight
  • Delta ring handguard attachment method - Compatible with aftermarket handguards for delta rings
  • 20mm Picatinny railed receiver - Ready for a red dot sight or scope
  • 6-Position M4/AR-15 buffer tube - Adjust the stock to fit your body type and loadout
  • Low profile "milspec" charging handle - Reduced snag points, steel latch for rigidity
  • "A2" Finger ridged pistol grip - Ideal for military-style builds, compatible with aftermarket real steel AR grips
  • "LE" Sliding stock - The classic "Law Enforcement" M4A1 stock design often seen on US Army M4A1 rifles
  • Grub Key adjustable HOP-up - Inside the upper receiver, accessible with the receiver split
  • WE V3 System Improvements:
    • Steel valve knocker
    • Redesigned bolt catch with steel contact surface
    • Upgraded rubber components for cold resistance
    • Redesigned & reinforced trigger group
    • Redesigned upper & lower receiver
  • Compatibility:
  • Is this your first GBBR? If so, see the "Special Instructions" section below or our GBBR Guide

Package Includes

  • WE M4A1 Open Bolt GBBR; V3 System
    • 30rnd V3 Green Gas Magazine
    • Loading tool
    • Barrel nut wrench
    • HOP-up Allen key

Special Instructions

We recommend using NUPROL 1.0 or equivalent PSI gas during summer to stay within site FPS limits, switching to standard Green Gas or Red Gas during winter.

This is a Gas Blowback Rifle. GBBRs require maintenance and careful handling and we do not recommend them for new skirmishers. Things to watch out for if this is your first GBBR:

  • The rifle can be put into "Safe" mode without first being cocked, but CANNOT be cocked in "safe" mode. Generally, the best way to store a GBBR is with the magazine removed, the rifle uncocked, and the fire selector set to "semi". Do not, under any circumstances, pull the charging handle while the platform is in "Safe" as this will break the fire control group.
  • The HOP-up adjuster for this WE V3 system GBBR is inside the upper receiver and is accessible with the rifle in "field stripped" condition.
  • GBBRs need to be cocked before the first shot, just like a GBB pistol. It is important that you do not double-load a GBBR, as this can break the nozzle. We recommend clearing the chamber of BBs with a cleaning rod in the event that you finish firing mid-magazine and the bolt does not lock back and show an empty chamber.
  • The faster you shoot a GBBR, the less accurate it will be. This is due to pressure variance as the gas reservoir cools down. Full auto is basically for fun, and these rifles run far better when used in semi-auto mode.
  • Like a GBB pistol, GBBR magazines require maintenance. We recommend leaving a small amount of gas inside the magazine when stored and not storing the magazines in a cold or damp environment. Magazine seals and valves will need lubrication and to be kept clear of dust and debris.

Specification

General

Weapon Construction External
Weapon Type
Assault Rifle
Over 18 Only Icon
Over 18
Yes
Icon UKARA - United Kingdom Airsoft Retailer Association
Defence / UKARA Required
Yes, No,
FPS Icon
FPS, using 0.20g BB
Approx.330fps ± 10%, using 0.20g BB
Site Legal Icon
Site Legal, using 0.20g BB
Yes
Screwdriver Icon
Pre-Built
Yes
Package
Included Items
  • Magazine
  • Tools
  • Loading tool
Skill Level Icon
User Skill Level
Advanced Player
Patrol Base - Warning Icon
Warnings
This GBBR cannot be put into the SAFE mode without first cocking the rifle. Do not force the selector into safe whilst the weapon is not cocked.

Weight and Dimension

Weight KG Icon
Weight (KG)
Approx. 2.646kg
Weapon Length Collapsed
Length (Collapsed)
77cm
Weapon Length Extended
Length (Extended)
85cm

Construction

Colour Wheel Greyscale
Primary Colour
Black
Construction Icon
Construction
Steel flash hider, handguard cap, barrel nut, dust cover, body pins & castle nut. Alloy outer barrel, front sight, receiver, carry handle & buffer tube. High density polymer stock, handguard & grip
Weapon Construction External
External Construction
Polymer
Alloy
Aluminium
Steel
Gearbox Icon
Internal Construction
Polymer
Alloy
Aluminium
Steel
Brass

Weapon Specific

Power Source Icon
Powered By
Electric
Blowback Icon
Blowback
Gas Blowback
Weapon Platform
Weapon Platform
Assault Rifle, M4 / AR-15 / M16, WE M4 GBBR,
Magazine Style Icon
Magazine Style
Long Gun Magazine, Assault Rifle, M4 / AR Platform, WE M4/AR-15 GBBR Magazine [V3 ONLY],
Fire Select Icon
Fire Selector
PatrolBase | Fire Select Safe
Safe
Patrol Base | Fire Select - Semi Automatic
Semi Automatic
Patrol Base | Full Automatic
Full Automatic
Weapon Safety Features Icon
Safety Features
Trigger Lock
Shooter Configuration Icon
Shooter Configuration
Right Handed
Weapon Configuration Icon
Weapon Configuration
Standard
Weapon Scale Icon
Weapon Scale
1:1
Suggested BB Weight
Suggested BB Weight
0.25g

Hop-Up

Hop-Up Unit Icon
Hop-Up Unit
Yes
Hop-Up Unit Adjuster Icon
Hop-Up Adjuster
Grub Key
Hop-Up Unit Location Icon
Hop-Up Location
Above the chamber, accessible with the platform in "Field Stripped" condition (receiver open, bolt & charging handle removed)

Furniture

Weapon Furniture Icon
Furniture
  • Railed Receiver
  • Finger Ridged Pistol Grip
  • AR Buffer Tube
  • Sliding Stock
  • Ghost Ring Ironsight
  • Bird Cage Flash Hider
  • Threaded Outer Barrel
  • Removable Carry Handle
  • sling points front and rear
  • AR Triangle front sight with sling loop
  • Bayonet lug
  • Ribbed handguards
  • Foldable trigger guard
Rail System Icon
Rail System
20mm RIS / RAS, 20mm Railed Receiver,
Icon Stock Positions
Stock Setting
Sliding, Multi-Position,
Weapon Length Extended
Stock Positions
6 Position
Sight Type Icon
Sight Type
Iron Sights, Aperture Iron Sight,
Sling Plate Icon
Sling Options
Stock, Loop, Gas Block,

Barrel

Outer Barrel Length (in)
14.5''
Icon Thread Type
Outer Barrel Thread Type
Male
Icon Thread Direction
Outer Barrel Thread Direction
CCW (Counter Clockwise)
Outer Barrel Thread Size
Outer Barrel Thread Size
14mm
Inner Barrel Diameter
Inner Barrel Diameter
6.04mm
Inner Barrel Length
Inner Barrel Length
370mm

Magazine Specific

Magazine Type
Magazine Type
Gas, Low Capacity,
Magazine BB Capacity
Magazine BB Capacity
Approx. 30 Rounds
Magazine BB Fill Method
Magazine BB Fill Method
Speed Loader
Magazine BB Fill Location
Magazine BB Fill Location
Top
Magazine Gas Fill Location
Magazine Gas Fill Location
Bottom
Magazine Gas Type
Magazine Gas Type
Green Gas

Gas Gun Specific

Gas Can Icon
Gas Compatability
Summer Gas, Green Gas, Red Gas,
Gas Can Icon
Gas Recommendation
Green Gas

Pistol Specific

Construction Icon
Slide Material
Alloy
Icon Pistol Slide
Pistol Slide Type
Bolt Carrier

Product Testing Data

Notepad Icon
Test Description
330 FPS +/- 10%
Notepad Icon
Tested Using
0.20g Delta Armory Diamond BBs & NUPROL 1.0 Blue Gas
Notepad Icon
Test Date
03/07/2025

Size guide

Joule Charts

Special Instructions

These table can be used as a reference to see if the BB weight you are using will be over acceptable Joulage limits at some Airsoft Sites in the UK. To check if the weight can be used chrono your weapon using the BB you intend to use, and then compare it to the chart.

FPS, Power and Joule Limits can vary from site to site, so please get in touch with where you're going to play with in advance to avoid disappointment.

Suggested limits are based on Joulage Limit rules used Halo Mill: Proving Grounds, with a 350fps limit for Automatic Replicas, 400fps for Semi-Automatic Replicas, and 500fps for Bolt Action Replicas.

Tap the tabs below to open the relevant chart for your replica.

Suggested limits are based on Joulage Limit rules used Halo Mill: Proving Grounds, and is the equivalent of 350fps, using 0.20g BB resulting in an upper limit of 1.14j.

Velocity BB Weight (Grams)
FPS 0.20 0.25 0.28 0.30 0.32 0.36 0.40 0.43 0.45 0.50
250 0.58 0.73 0.81 0.87 0.93 1.05 1.16 1.25 1.31 1.45
260 0.63 0.79 0.88 0.94 1.00 1.13 1.26 1.35 1.41 1.57
270 0.68 0.85 0.95 1.02 1.08 1.22 1.35 1.46 1.52 1.69
280 0.73 0.91 1.02 1.09 1.17 1.31 1.46 1.57 1.64 1.82
290 0.78 0.98 1.09 1.17 1.25 1.41 1.56 1.68 1.76 1.95
300 0.84 1.05 1.17 1.25 1.34 1.51 1.67 1.80 1.88 2.09
310 0.89 1.12 1.25 1.34 1.43 1.61 1.79 1.92 2.01 2.23
320 0.95 1.19 1.33 1.43 1.52 1.71 1.90 2.05 2.14 2.38
325 0.98 1.23 1.37 1.47 1.57 1.77 1.96 2.11 2.21 2.45
328 1.00 1.25 1.40 1.50 1.60 1.80 2.00 2.15 2.25 2.50
330 1.01 1.26 1.42 1.52 1.62 1.82 2.02 2.18 2.28 2.53
335 1.04 1.30 1.46 1.56 1.67 1.88 2.09 2.24 2.35 2.61
340 1.07 1.34 1.50 1.61 1.72 1.93 2.15 2.31 2.42 2.68
345 1.11 1.38 1.55 1.66 1.77 1.99 2.21 2.38 2.49 2.76
350 1.14 1.42 1.59 1.71 1.82 2.05 2.28 2.45 2.56 2.85
355 1.17 1.46 1.64 1.76 1.87 2.11 2.34 2.52 2.63 2.93
360 1.20 1.51 1.69 1.81 1.93 2.17 2.41 2.59 2.71 3.01

Suggested limits are based on Joulage Limit rules used at Halo Mill: Proving Grounds, and is the equivalent of 400fps, using 0.20g BB resulting in an upper limit of 1.49j.

Velocity BB Weight (Grams)
FPS 0.20 0.25 0.28 0.30 0.32 0.36 0.40 0.43 0.45 0.50
250 0.58 0.73 0.81 0.87 0.93 1.05 1.16 1.25 1.31 1.45
260 0.63 0.79 0.88 0.94 1.00 1.13 1.26 1.35 1.41 1.57
270 0.68 0.85 0.95 1.02 1.08 1.22 1.35 1.46 1.52 1.69
280 0.73 0.91 1.02 1.09 1.17 1.31 1.46 1.57 1.64 1.82
290 0.78 0.98 1.09 1.17 1.25 1.41 1.56 1.68 1.76 1.95
300 0.84 1.05 1.17 1.25 1.34 1.51 1.67 1.80 1.88 2.09
310 0.89 1.12 1.25 1.34 1.43 1.61 1.79 1.92 2.01 2.23
320 0.95 1.19 1.33 1.43 1.52 1.71 1.90 2.05 2.14 2.38
330 1.01 1.26 1.42 1.52 1.62 1.82 2.02 2.18 2.28 2.53
340 1.07 1.34 1.50 1.61 1.72 1.93 2.15 2.31 2.42 2.68
350 1.14 1.42 1.59 1.71 1.82 2.05 2.28 2.45 2.56 2.85
360 1.20 1.51 1.69 1.81 1.93 2.17 2.41 2.59 2.71 3.01
370 1.27 1.59 1.78 1.91 2.03 2.29 2.54 2.73 2.86 3.18
380 1.34 1.68 1.88 2.01 2.15 2.41 2.68 2.88 3.02 3.35
390 1.41 1.77 1.98 2.12 2.26 2.54 2.83 3.04 3.18 3.53
400 1.49 1.86 2.08 2.23 2.38 2.68 2.97 3.20 3.34 3.72
410 1.56 1.95 2.19 2.34 2.50 2.81 3.12 3.36 3.51 3.90

Suggested limits are based on Joulage Limit rules used at Halo Mill: Proving Grounds, and is the equivalent of 500fps, using 0.20g BB resulting in an upper limit of 2.32j.

Velocity BB Weight (Grams)
FPS 0.20 0.25 0.28 0.30 0.32 0.36 0.40 0.43 0.45 0.50
250 0.58 0.73 0.81 0.87 0.93 1.05 1.16 1.25 1.31 1.45
260 0.63 0.79 0.88 0.94 1.00 1.13 1.26 1.35 1.41 1.57
270 0.68 0.85 0.95 1.02 1.08 1.22 1.35 1.46 1.52 1.69
280 0.73 0.91 1.02 1.09 1.17 1.31 1.46 1.57 1.64 1.82
290 0.78 0.98 1.09 1.17 1.25 1.41 1.56 1.68 1.76 1.95
300 0.84 1.05 1.17 1.25 1.34 1.51 1.67 1.80 1.88 2.09
310 0.89 1.12 1.25 1.34 1.43 1.61 1.79 1.92 2.01 2.23
320 0.95 1.19 1.33 1.43 1.52 1.71 1.90 2.05 2.14 2.38
330 1.01 1.26 1.42 1.52 1.62 1.82 2.02 2.18 2.28 2.53
340 1.07 1.34 1.50 1.61 1.72 1.93 2.15 2.31 2.42 2.68
350 1.14 1.42 1.59 1.71 1.82 2.05 2.28 2.45 2.56 2.85
360 1.20 1.51 1.69 1.81 1.93 2.17 2.41 2.59 2.71 3.01
370 1.27 1.59 1.78 1.91 2.03 2.29 2.54 2.73 2.86 3.18
380 1.34 1.68 1.88 2.01 2.15 2.41 2.68 2.88 3.02 3.35
390 1.41 1.77 1.98 2.12 2.26 2.54 2.83 3.04 3.18 3.53
400 1.49 1.86 2.08 2.23 2.38 2.68 2.97 3.20 3.34 3.72
410 1.56 1.95 2.19 2.34 2.50 2.81 3.12 3.36 3.51 3.90
420 1.64 2.05 2.29 2.46 2.62 2.95 3.28 3.52 3.69 4.10
430 1.72 2.15 2.40 2.58 2.75 3.09 3.44 3.69 3.86 4.29
440 1.80 2.25 2.52 2.70 2.88 3.24 3.60 3.87 4.05 4.50
450 1.88 2.35 2.63 2.82 3.01 3.39 3.76 4.04 4.23 4.70
460 1.97 2.46 2.75 2.95 3.15 3.54 3.93 4.23 4.42 4.91
470 2.05 2.57 2.87 3.08 3.28 3.69 4.10 4.41 4.62 5.13
480 2.14 2.68 3.00 3.21 3.42 3.85 4.28 4.60 4.82 5.35
490 2.23 2.79 3.12 3.35 3.57 4.02 4.46 4.80 5.02 5.58
500 2.32 2.90 3.25 3.48 3.72 4.18 4.65 4.99 5.23 5.81
510 2.42 3.02 3.38 3.62 3.87 4.35 4.83 5.20 5.44 6.04