Rail System for CYMA PP-19 Bizon (AIRSOFT)

thingiverse

Designed this rail system for the CYMA PP-19 Bizon so I could run an optic without the bulk and inconvenience of a side-mount. I've uploaded a 'slim' top section for some pistol-type optics and a 'standard' top section that can be used with any picatinny optic. Unless you need the slim rail, the standard is recommended. The CYMA PP19 uses a 'short' front block which means the standard AK sight rail adapter will not fit. A standard AK side mount will fit, but would need to come off to access the battery compartment etc. This system allows the dust cover to be removed without disturbing your sight, is extremely minimal, and is offset rearward for better eye relief. I split the print into two separate pieces which are bolted together due to the complex geometry involved. This also allows for different upper sections to be designed by myself and others. The lower section re-uses a screw from the factory rear sight but you will need to find a m4x22mm bolt and nut for the front of it. The upper part is attached to the lower by two m4X10mm bolts & nuts. To install this rail system remove the rear sight and sight-spring underneath. Fit the lower section into the sight block - the lower section is tight by design, some careful filing may be needed for a good fit. Once it's fitted, secure it with the screw that formerly held the rear sight spring and thread the long M4 through the side of the sight block. Make sure you installed the nuts for the upper section first! The upper section simply bolts onto the lower and should be centered / held true by the fasteners. Re-check these bolts periodically - PLA can compress over time and loosen up the rail system. The slim upper section has a ~1.75x12mm slot cut in it at a 14 degree angle so an optic protector can be fabricated from a sheet of 1/16" polycarbonate: leave an ~12mm wide and 10mm long tab on the bottom that can be inserted into the rail system. The shield can be glued in or simply 'friction fit'. Recommended printing at 0.1mm layer height, 1.2mm shell thickness, and 45% infill. To my knowledge the PP19 is the only AEG this rail system will fit on - if you happen to know of any other AEGs that use the same short front block please let us know!