Cylinder Head MK.II V2/3 Type, Uni

The AEG Mk.III uni V2/3 cylinder head is a universal part designed for V2 and V3 gearboxes from various manufacturers. Thanks to its medium-length nozzle tip, it is optimized for nozzles in the 20–24 mm range, typically used in AK, AR15, and similar platforms.

This model is available in two nozzle tip versions:

• Standard – nozzle tip diameter 5.35 mm
• Extra Fit – enlarged nozzle tip diameter 5.40 mm

The Extra Fit version reduces play between the cylinder head and the nozzle, significantly helping to prevent so-called mid-cap syndrome and improving feeding stability. The Standard version is the classic universal option for regular builds.

A major advantage of the Mk.III cylinder head is its increased tappet plate lift compared to standard cylinder head designs. This allows the use of a nozzle up to 1 mm longer, improving the seal between the nozzle and the hop-up bucking during the shot while also helping eliminate possible feeding issues without sacrificing proper function.

The unique mounting system ensures truly universal compatibility with both V2 and V3 gearboxes, while the locking pin holes are also designed for optimal fitment in Retro Arms gearboxes.

Compared to the older Mk.I version, the Mk.III brings several important improvements. It features H+PTFE surface treatment, an extended nozzle tip length, a revised nozzle tip diameter, and a redesigned impact pad for better energy distribution during piston impact.

The body of the cylinder head is made from EN AW 7075-T6 aerospace aluminum with H+PTFE coating, providing excellent sliding properties while maintaining high wear resistance.

Impact pad hardness options are available in several variants:

• 70 sh for springs up to SP130
• 80 sh for springs up to SP160
• 90 sh for springs SP170 and stronger

For high rate-of-fire and high-capacity guns, such as machine guns intended for long bursts, it is recommended to use one step lower spring strength relative to the selected impact pad hardness for added safety.

A version without impact pad is also available for easy use with a custom PU pad or Sorbopad depending on your build and AOE setup.

The product is made in the Czech Republic.

Key features:

• universal cylinder head for AEG V2 and V3 gearboxes
• suitable for 20–24 mm nozzles
• designed for AK, AR15, and similar platforms
• available versions:
  • Standard 5.35 mm
  • Extra Fit 5.40 mm
• Extra Fit reduces nozzle play and helps prevent mid-cap syndrome
• increased tappet plate lift
• allows the use of a nozzle up to 1 mm longer
• improved seal between the nozzle and hop-up bucking
• universal fit, also optimized for Retro Arms gearboxes
• made from EN AW 7075-T6
• H+PTFE surface treatment
• O-rings made of NBR 70 sh
• made in the Czech Republic