4UAD 4UANTUM Magnus Pro Hop-Up Chamber, GHK / VFC M4 GBB Series
The 4UAD 4UANTUM Magnus Pro is a precision CNC-machined TDC hop-up chamber designed for compatible GHK V3 and VFC AR/M4 GBB rifles. Machined from a solid billet of 6061 aluminium, the chamber combines true vertical hop adjustment, self-centring inner-barrel retention and precise bucking alignment to provide a stable and repeatable hop-up setup.
The Magnus Pro is designed around one simple goal: keeping the inner barrel, hop-up bucking and pressure point correctly aligned. Reducing unwanted movement and variation between these components helps create a more consistent backspin and predictable BB trajectory.
True vertical TDC adjustment
The Magnus Pro uses a true TDC (Top Dead Center) adjustment system. As the hop-up is adjusted, the pressure mechanism moves vertically rather than changing the angle of the pressure point.
This means the hop-up pressure remains centred in the same position throughout the adjustment range, helping maintain an even backspin and reducing the possibility of unwanted side spin.
Self-centring tri-lug barrel locking
The chamber uses a self-centring three-point locking system to position and secure the inner barrel. Instead of simply holding the barrel in place from one direction, the tri-lug design centres it inside the chamber while locking it firmly against unwanted movement.
A precisely machined CNC bucking sleeve also supports the hop-up bucking, helping maintain its correct orientation and preventing it from twisting or shifting during use.
Easy adjustment through the ejection port
The Magnus Pro adjustment dial can be accessed directly through the replica's ejection port. Hop-up can be adjusted with a suitable pointed tool without removing the hop-up chamber or disassembling the rifle.
This makes fine adjustment significantly easier, especially when tuning the replica for different BB weights or environmental conditions.
GHK and VFC installation
-
GHK AR GBB V3: install without the included spacer
-
VFC AR/M4 GBB: install with the included spacer
Please note that GHK compatibility refers to the V3 AR GBB system. The chamber is not intended for the older GHK V2 system. Compatibility should also be checked before installation if the replica uses non-standard receiver, outer-barrel or hop-up components.
Recommended hop-up bucking
For the Magnus Pro chamber, we recommend the 4UAD 4UANTUM Friction Pro High Performance GBB Bucking. Its centred friction patch complements the Magnus Pro's TDC system and precise bucking alignment.
Features
- Precision CNC-machined hop-up chamber for compatible GHK V3 and VFC AR/M4 GBB rifles
- Machined from solid 6061 aluminium billet
- True vertical TDC hop-up adjustment
- Pressure point remains centred throughout the adjustment range
- Self-centring tri-lug inner-barrel locking system
- Helps keep the inner barrel firmly and consistently aligned
- CNC-machined bucking sleeve maintains correct bucking orientation
- Hop-up adjustment accessible through the ejection port
- Can be adjusted with a suitable pointed tool without disassembling the rifle
- Included spacer allows installation in VFC AR GBB systems
Compatibility
- GHK AR / M4 GBB V3 system - install without the included spacer
- VFC AR / M4 GBB system - install with the included spacer
- Not compatible with the older GHK V2 system
Not included
- Hop-up bucking
- Inner barrel
Installation instructions
Read the manufacturer's installation instructions before installation:
4UAD Magnus Pro AR installation guide
4UAD also provides a video guide for the Magnus Pro AR:
4UAD Magnus Pro AR installation video
Technical specifications
- Manufacturer: 4UAD
- Series: 4UANTUM
- Model: Magnus Pro AR
- Product type: TDC hop-up chamber
- Compatibility: GHK AR GBB V3 / VFC AR GBB
- Material: CNC-machined 6061 aluminium
- Hop-up adjustment: vertical TDC
- Inner-barrel retention: self-centring tri-lug system
- Adjustment access: through the ejection port
