Cylinder head AEG Mk.II uni V2/3 – standard – EF

• Medium length nozzle guide rod – optimal for nozzle length in 20–24 mm range (AK, AR15 or similar type)
• Extra Fit nozzle guide rod with enlarged diameter of 5.40 mm (standard version with diameter of 5.35 mm also available). The increased diameter of the nozzle guide rod eliminates nozzle play and significantly helps to prevent "mid-cap syndrome".
• Increased tappet plate stroke length compared with standard cylinder heads
  • Allows for the use of up to 1 mm longer nozzle in order to provide a tighter fit between the nozzle and hop-up bucking during shooting
  • Removes potential feeding issues while retaining perfect tightness between the nozzle and hop-up bucking during shooting
• Unique system for the mounting of the cylinder head inside the gearbox makes this cylinder head a truly universal solution for V2 and V3 gearboxes from different manufacturers
• Mounting pin holes are designed for optimal fit into the RetroArms gearboxes
• Rubber impact pads made from polyurethane (PU) rubber with 70, 80 and 90 sh hardness with maximized impact area - 3 mm thickness
  • 70 sh for springs of up to SP130 strength
  • 80 sh for springs of up to SP160 strength
  • 90 sh for springs of SP170 strength and higher
  • For high fire rate and high-capacity guns (for example machine guns), where 100+BB bursts can be expected, we recommend using a spring one level weaker than stated above (e.g. maximum spring strength of SP120 for 70 sh hardness)
• Available also in version without the impact rubber pad in order to be used with other available PU impact pads or Sorbopad in selected hardness, according to selected spring and pad height in order to adjust AOE
• Compared with Mk.I version, Mk. II has an added H+PTFE surface finish, longer nozzle pilot, adjusted nozzle pilot diameter and reworked impact rubber pad design for a more efficient impact force distribution
• Made from EN AW 7075-T6 aircraft-grade duralumin with proven H+PTFE surface finish for ideal sliding properties while retaining high abrasion resistance of the surface
• The Impact rubber pad is made from polyurethane (PU) rubber in selected hardness and O-rings are made from NBR 70 sh
• Made in the Czech Republic

Package contents

• 1 cylinder head with glued on impact rubber pad in selected hardness, fitted with two O-rings (21×1,5)
• 2 fixing grub screw M3×3
• 2 fixing grub screw M3×2

EPeS cylinder head offers two unique design solutions:

Increased tappet plate stroke

Compared with standard cylinder head designs, the surface which stops the tappet plate in its rearmost position has been moved towards the rear of the cylinder head. With adequate tappet plate (e.g. SHS) or with cam that increases the length of the stroke, it is possible to use a nozzle up to 1 mm longer than in standard designs. This innovation will be especially welcomed by the owners of the V2 gearboxes, as V3 is already designed with longer tappet plate stroke length.

You can then, e.g. in AR15 setups, use 22 mm long nozzle which offers tighter sealing of the nozzle to hop-up contact (or rather nozzle to hop-up bucking lip). The longer nozzle also helps to improve the feeding process in problematic cases and therefore solves the eternal dilemma: "A longer nozzle will provide better tightness, but the gun won't feed BBs as reliably or it will stop feeding at all. A shorter nozzle will feed reliably, but it will lose performance." With the EPeS airsoft Mk.II cylinder head you no longer need to make compromises. Instead, you can pick both choices: high performance and reliable feeding.

Unique system for fitting the cylinder head inside the gearbox

The EPeS airsoft Mk.II cylinder head has two M3 threads for grub bolts. These bolts are driven from the front of the cylinder head and allow for smaller pin holes for the gearbox mounting pins. This way, the cylinder head can always be placed neatly on the front plate of the gearbox with no allowance. This ensures the issue-free operation of the air system without performance losses or other common problems leading to early wearing out of the parts.

Loosely fitting cylinder head allows for too large axial sway of the nozzle. This effect introduces a host of issues (loss of performance, inconsistent performance, nozzle jams in the hop-up chamber, feeding issues, etc.). Additionally, it also introduces uneven contact between the cylinder head and piston head impact rubber pads, which can damage the piston head or the piston itself.

Installation of the cylinder head is easy. By tightening the front grub screw, the size of the hole for the gearbox mounting pin is adjusted (and also the amount of allowance space for the mounting pin).. Keep adjusting by trial and error until you reach the tight fit of the cylinder head. This mechanism allows for a truly universal solution for seating the cylinder head in most of the available gearboxes. The default position of the pinholes is optimized for gearboxes from the Czech manufacturer Retro Arms.
Attention: We strongly recommend affixing the grub bolts using a high strength thread locking glue.

Example of cylinder modification to take advantage of the maximum tappet plate stroke of the EPES cylinder head: