MilSim Labs 40mm BullPup Launcher (airsoft)

We have deprecated our 40mm bullpup, while we still have the molds and will make them made to order if people want, it was time to let this out for the printing crowd

Designed as a resin cast kit molded off 3d printed masters it comes from an era when 3d printers had little control over wall thickness and infill so I don't have any print settings, you are on your own as to what would be stable enuff to hold up to the forces involved

Build video https://www.youtube.com/watch?v=dxU_VrkY_WI
use video https://www.youtube.com/watch?v=aitEjiQFT94
Crono video showing 2x the FPS vs a long m 203 barrel https://www.youtube.com/watch?v=VER1k6xFqVA

The firing pin and trigger have some legs that need cut off, they are the remnant of pour spouts that were used when it was a molded item, you can see how they are supposed to look in the build video

you will need

super glue
1/4" safety pin for the breach lock http://www.homedepot.com/p/Everbilt-1-4-in-x-2-in-Zinc-Plated-Round-Head-Wire-Lock-Pin-807468/204276210?N=5yc1vZc2d3

a ¼” bolt and lock nut or ¼” safety pin or (preferred)

a ¼”odX1.25” Steel Post and Screw aka Chicago Screws/Barrel Nut for the breach pivot

3 M3 X25mm bolts and 2 m3 hex nuts

16-24” of 1.5” sch 40 pvc pipe (18" was found to be about prime)

rubbing alcohol and paper towels
sandpaper, sharp knife, file

sand and clean ALL surfaces with alcohol or the paint will not stick, I have found drywall sanding screens to work very well for this plastic.

Put one m3 bolt through the breach and firing pin to hold the pin in place
use the other m3 bolts to mount the sights to the rail, it should be a tight fit and allow the bolt the cut its own threads as it goes in, the hex nuts allow you to adjust the tension on the sight to your liking
glue the chamber in place over the pipe
after glue sets attach the breach with your hardware of choice

shoulder the launcher and hold the grip up to it, mark it where it's comfortable to you.
glue the fiberglass rod to the trigger to form the trigger linkage
with the breach open, put the trigger in the grip and threw the whole in the chamber, place the grip on your marks, set the trigger so you have enough space to comfortably get you finger in front of it and mark the fiberglass rod where it comes out of the breach.
Cut the rod at the mark and sand the end so it’s a bit rounded.
Put the linkage through the hole in the chamber and glue the grip down over the trigger at your marks
shoulder the launcher and place the sights on top, move them around till you find a spot you like, check that when looking through the top hole you can see clearly and the barrel doesn’t block your line of sight, for me, this happens when the rail is placed about 6” back from the muzzle, mark and glue down
remove the front/rear sight and breach
give a quick wipe down to remove any fingerprints or grime that may have happened while assembling and paint in your color of choice, make sure not to go too heavy near the fiberglass rod, you don’t want to cause it to stick to the barrel and ruin your project.
let dry and reassemble the parts

A word on the sites
at 100'
the bottom hole gives you a 1-degree angle, aiming point 1.7’ above level

the middle hole is 6.1 degrees aiming point 9’ higher than the bottom hole

the top hole is 11.1 degrees aiming point 9’ higher then the middle hole

the left and right windage posts are 7' in either direction from the center post
so 1/2 that at 50', +50% for 150 and double for 200'
should help you adjust when you miss a shot