The 
G&G TR4-18
 is a high-performance, full-metal electric airsoft rifle (AEG) that is part of G&G's "Top Tech" advanced line, known for its reliable internals and realistic features like a pneumatic blowback system
 
Key Features
Construction: The rifle features a durable, mostly metal construction, including the receiver, barrel assembly, and RIS handguard, giving it a solid, realistic feel.
Pneumatic Blowback: It utilizes G&G's pneumatic blowback system, which uses air pressure to simulate a realistic recoil action without putting extra strain on the gearbox or the battery, unlike some electric blowback systems.
Internal Components: The TR4-18 boasts strong internal components, including a full metal Version 2 gearbox with 8mm ball bearings, a high-torque motor, and a 6.03mm tight-bore inner barrel for improved accuracy. Some models also include a built-in MOSFET for Li-Po battery protection.
Adjustable Features: It includes a 6-position adjustable Crane-style stock for battery storage, a full-length top rail for mounting optics, and an adjustable hop-up unit.
Functioning Controls: A unique feature is the functioning forward assist, which acts as a spring tension release to prolong the spring's life when storing the rifle. It also has a functional charging handle and bolt catch mechanism. 
Performance and User Experience
Performance: Reviewers praise the G&G TR4-18 for excellent out-of-the-box performance, with consistent accuracy and good range, capable of hitting targets at significant distances.
Aesthetics: The rifle is based on the Heckler & Koch HK416 model and has a high-quality finish.
Ease of Use: It is considered user-friendly for both intermediate and veteran players and is wired to the rear for easier battery installation in the stock.
Magazine Compatibility: The included 450-round high-capacity magazine is compatible with most other M4/M16 series airsoft AEG magazines, offering flexibility for accessories. 
Technical Specifications
Specification 
Details
Length
790mm - 885mm (adjustable)
Weight
~2900g (around 6.4 lbs)
Inner Barrel Length
357mm (carbine version); 275mm (light/short version)
Muzzle Velocity
310-340 FPS with 0.20g BBs (some versions may reach 380-390 FPS)
Magazine Capacity
450 BBs (Hi-Capacity)
Power Source
Electric (AEG), Li-Po ready with MOSFET
Fire Modes
Safe / Semi-Auto / Full-Auto
Hop-Up
Adjustable
Thread Direction
14mm Negative (Counter-Clockwise)