Hop-Up chamber for VFC-HK417 / SR25 / M110 / G28

T-N.T. CNC Hop-Up Chamber for VFC HK417 / M110 / SR25 / G28 and APFG XM7 is a precision upgrade chamber for GBB airsoft rifles. The design focuses on precise BB feeding, stable inner barrel positioning and broad compatibility with standard GBB hop-up buckings and inner barrels.

The kit includes a T-N.T. H.L.R. GBB 60° hop-up bucking and two different dedicated tensioners. This allows the contact configuration to be selected according to the bucking, BBs and desired hop-up characteristics.

The chamber supports standard GBB inner barrels featuring a third locking groove. The integrated bucking side-alignment design helps maintain consistent bucking positioning, while the chamber construction ensures precise BB feeding alignment.

The inner barrel is securely retained in the chamber by a U-Clip. The internal locating groove of the supplied U-Clip has a width of 7.0 mm.

Two types of dedicated tensioners:
- Flat tensioner with a narrow contact patch – provides a narrower contact area on the hop-up bucking.
- Curved tensioner with a wide contact patch – provides a wider contact area on the hop-up bucking.

Main features:
- Designed for VFC HK417 / M110 / SR25 / G28 and APFG XM7 GBB.
- Compatible with standard GBB hop-up buckings.
- Supports standard GBB inner barrels featuring a third locking groove.
- Bucking side alignment – helps maintain consistent bucking positioning.
- Precise BB feeding alignment – chamber design ensures correct alignment during BB feeding.
- U-Clip design – securely retains the inner barrel within the chamber.
- Two dedicated tensioners – allows a choice between narrow and wide contact patches.

Package contents:
- T-N.T. H.L.R. GBB 60° hop-up bucking – 1 pc
- T-N.T. VFC HK417 hop-up chamber assembly – 1 pc
- Dedicated tensioner – 2 pcs

Compatibility:
- VFC HK417 GBB
- VFC M110 GBB
- VFC SR25 GBB
- VFC G28 GBB
- APFG XM7 GBB
- Standard GBB hop-up buckings and corresponding GBB-spec inner barrels.

Important for APFG XM7:
When installing the chamber in an APFG XM7, the original XM7 hop-up nub must be used. The supplied dedicated tensioners intended for the other listed platforms should therefore not be used for the XM7 installation.

Inner barrel compatibility note:
The internal locating groove of the supplied U-Clip is 7.0 mm wide. If the corresponding locating groove on your inner barrel exceeds 7.0 mm in width, the U-Clip may not seat correctly. In this case, minor fitting may be required – either carefully enlarging the locating groove inside the U-Clip or reducing the width of the corresponding locating groove on the inner barrel.

Dimensions and manufacturing tolerances vary between inner barrel manufacturers, so direct drop-in compatibility with every aftermarket inner barrel cannot be guaranteed. Once correctly fitted, this does not negatively affect the function or performance of the assembly.

Hop-up pressure adjustment note:
The internal dimensions of VFC HK417, M110, SR25 and related platforms may vary slightly between models and production batches. If the hop-up contact pressure is insufficient after installation, the manufacturer recommends placing a spacer approximately 0.2–0.3 mm thick (for example, a piece of business card or playing card) beneath the front end of the original adjustment arm. This increases the pressure applied to the bucking and provides a greater hop-up adjustment range.

Installation note:
Due to differences in dimensions, manufacturing tolerances and machining methods among components from different manufacturers, direct compatibility with every aftermarket part cannot be guaranteed. In some installations, minor fitting, adjustment or modification may be required. Installation by users with basic mechanical and DIY experience or by a qualified airsoft technician is recommended.