WE M4 DIY NPAS Float Valve

Following this video, these are premade STLs for rocket valves with various internal diameters for control of muzzle velocity.  The stock valve is 4.5mm, I use the 4mm one here in the UK and last chrono was 344, 343, 346, 348 so they function perfectly fine. 

All you need is a pin/thin nail, a lighter, and a 10mm M3 grub screw.