Externals: Handguards, Stocks & Receivers

Handguards, stocks and grips

A new handguard is the most visible external upgrade: a slim M-LOK or KeyMod rail saves weight over a quad Picatinny RIS and gives you mounting slots exactly where you want a light or a grip. Stocks change length of pull and battery space; a crane stock holds a nunchuck battery, a PDW stock makes a carbine compact. Pistol grips with a different angle and a motor plate that lets you adjust motor height improve comfort and trigger response at the same time.

Receivers and outer barrels

A metal receiver set replaces a polymer body for stiffness and a solid feel, and licensed versions carry real trademarks. Outer barrels in different lengths let you build a long rifle or a short CQB gun on the same lower, with a 14 mm CCW thread for a suppressor; the thread filter lists CW and CCW options. Flash hiders, gas blocks and barrel nuts complete the front end.

Compatibility between brands

Most M4 AEG externals follow the Tokyo Marui standard and fit between brands, but receiver pins, buffer tube threads and handguard nuts vary enough to check the product notes. AK, G36, MP5 and SCAR parts are more brand-specific, and GBB rifles use their own dimensions. Use the platform and rail system filters, and remember that externals are unrestricted parts with no age limit even though the complete guns are not.