EPeS Hop-up chamber M249

EPeS Hop-up Chamber for M249 introduces a revolutionary design developed after extensive research, combining high performance with simple operation. This version is specifically designed for M249 machine guns with a brick-type gearbox, including models from A&K, Retro Arms, Bullgear, and others.
Not compatible with the model A&K M60 and M249 Featherweight with a plastic body and V2 gearbox.
Fine adjustment of hop-up pressure can be done within a 360° range using the adjustment wheel, marked for easy orientation. The hop-up chamber features a perfectly tuned shape of the internal seating for the hop-up rubber collar, ensuring successful testing with various hop-up rubbers available in the market (EPeS recommends Maple Leaf rubbers).
The chamber is made from aircraft-grade aluminum EN AW 7075-T6 with an H+PTFE surface treatment, offering not only high manufacturing quality but also optimal performance.
Additionally, the chamber can be secured against rotation directly in the weapon body using the included worm screw. A CNC nozzle will not be included with the chamber. The recommended length of the nozzle is 21.4-22.0 mm (optimal length 21.6 mm), depending on other components in the weapon.

Innovative Chamber Mounting
For precise shooting and seamless feeding, it's essential that the chamber cannot rotate around its axis. The chamber is standardly fixed against rotation in its axis using a groove in the weapon's feeding chute.
An alternative method of fixing the chamber against rotation is using a thread at the top of the chamber near the adjustment ring for hop-up regulation. With the included worm screw, M3×12, the chamber can be fixed in the groove of the central part of the weapon body. This option is particularly suitable when the option of quick disassembly of the outer barrel is not used. If you want to remove the barrel using this method of chamber fixation, it is necessary to unscrew the fixing worm screw first.
The third option (for example, for access to the battery in the handguard) is to use the groove at the top of the chamber and fix the chamber directly in the part of the outer barrel housing. Modification of the housing is necessary, but it allows fixation of the chamber against rotation while maintaining axial movement in the direction of the spring pressure on the gearbox. This preserves the original function of quick disassembly of the outer barrel - this movement of the chamber is needed when locking the outer barrel into the weapon body.

Main Advantages of the M249 Chamber:

• Designed for M249 machine guns with a brick-type gearbox (A&K, Classic Army, Retro Arms, Bullgear, and others)
• Fine adjustment of hop-up pressure - a 360° range of the adjustment wheel
• Marked direction of hop-up regulation
• Perfectly tuned and long-developed shape of the internal seating for the hop-up rubber collar - successfully tested with most available hop-up rubbers on the market
• Construction of the seating for AEG hop rubbers with a standard length collar (e.g. Systema). For use with hop-up rubbers with a longer collar, use the included spacer - more on the issue of the length of the hop-up rubber collar
• Limitation of the play of the hop-up chamber in the gearbox hole using the included O-rings of two sizes
• Vertically seated pressure of the hop-up rubber - works great with Maple Leaf hop-up rubbers
• Groove at the top of the hop-up chamber for the possibility of fixing it in the outer barrel housing
• Possibility to secure the chamber against rotation directly in the weapon body using the included worm screw.
• Replaceable pin for the axial locking of the hop-up chamber in the feeder - if necessary, a longer pin can be installed to ensure a perfect fit.
• Made of aircraft-grade aluminum EN AW 7075-T6 with H+PTFE surface treatment
• Made in the Czech Republic

Package Contents:

• Hop-up chamber
• Adjustment ring for hop-up pressure
• Faced pressure roller of the hop-up
• 2× safety O-ring of the adjustment ring (9×1.5)
• 2× O-ring for limiting the play of the chamber in the gearbox hole (6×1 and 9×1)
• 2× spacer for the hop-up rubber collar (0.1 + 0.2 mm)
• Fixing screws for securing the barrel in the hop-up chamber (2× M3×5 + 2× M3×4 - belong to the upper and lower holes in the groove)
• Worm screw for fixing the hop-up chamber in the weapon body (M3×12)