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TDC MAGNUS PRO hop-up chamber by 4UAD for GHK / VFC AR15 in black.
Designed exclusively for GHK / VFC AR15 gas blowback rifles such as M4, HK416A5 and MK18.
Precisely machined CNC chamber made from 6061 aluminum.
Vertical TDC system ensures perfectly stable and consistent hop-up pressure.
Enhanced self-centering barrel interface for maximum accuracy.
: UMAREX
UMAR036
Airsoft assault rifle HK416 A5 in GBBR version and Black finish. Umarex combines realistic details of a metal body with tuned internal parts by VFC. Fully licensed rifle with Heckler & Koch marking. Enhanced Gen3 with Hop-up adjusted via gas block, steel trigger mechanism, and stronger Blowback! The Only Easy Day Was Yesterday!
: UMAREX
UMAR037
Airsoft assault rifle HK416 A5 in GBBR version and Tan (RAL 8000) finish. Umarex combines realistic details of a metal body with tuned internal parts by VFC. Fully licensed rifle with Heckler & Koch marking. Enhanced Gen3 with Hop-up adjusted via gas block, steel trigger mechanism, and stronger Blowback! The Only Easy Day Was Yesterday!
4UAD002
High-quality 4UANTUM Friction hop-up bucking by 4UAD for GBB / VSR rifles. Redesigned nub for perfect range and accuracy. Capable of hop-up for heavy sniper BBs up to 0.48g. Traditional single-point nub with minimal room for BB misalignment. Accuracy, range, and precision, that’s what it’s all about!
4UAD006
4UANTUM SEAL Silicone Grease for Sealing by 4UAD in a transparent finish. High-viscosity sealing grease. Ideal for sealing repairs and preventing leaks from damaged O-rings. Suitable for electric AEGs, manual, GBB, CO2, and HPA gas guns. Content: 15 ml. Easy application with a pen applicator.
4UAD014
MAGNUS PRO AR replacement hop-up bucking sleeve by 4UANTUM in black. For gas airsoft rifles GHK / VFC AR15 such as M4, HK416A5 and MK18. Improves hop-up bucking stability and alignment. Better sealing and consistent performance with every shot.
Looking for the most accurate and most stable hop-up chamber for your GHK or VFC AR15 GBB rifle? Want to shoot farther with higher precision? Need to hit targets consistently at any distance while using heavier BBs? The 4UAD MAGNUS PRO is made exactly for that. This hop-up chamber represents the absolute peak of modern TDC designs. It is CNC machined from a solid block of 6061 aircraft-grade aluminum and uses a true TDC (Top Dead Center) mechanism, meaning the pressure on the bucking is applied straight from above and always evenly. Thanks to its patented self-centering tri-lug barrel lock, the inner barrel stays perfectly centered and fixed without any play. The design also includes a CNC bucking collar that keeps the bucking aligned and provides stable muzzle velocity. Adjusting the hop-up is extremely simple — the adjustment wheel is accessible through the ejection port, so you can fine-tune the setting without disassembling the rifle (using a 1.5 mm hex key or a pointed tool). The chamber is fully compatible with both GHK and VFC platforms (M4/AR15/HK416); for VFC systems, a dedicated spacer is included for perfect fitment. For anyone who demands consistent performance, perfectly straight flight paths, and long-term reliability, the MAGNUS PRO is the ultimate upgrade. Works best with the 4UANTUM Friction GBB bucking (not included).
Installation demo

Pair of pressure segments

Complete package contents
| Color | Black |
| Hop-Up chamber material | Metal |