When I think of DIY airsoft mods, I think of ‘someone’ sat down with a rusty file; bodging away while fending off gigantic marauding cats. Then finishing off with a bit of black marker pen, to hide the mess. Or, simply sweeping all the bits into a black plastic bin bag and sending it to someone who actually knows what they’re doing. Obviously we all have different skill sets, but sadly the above is what I’ve done in the past (and why I rarely do it anymore).
Elliot fitted a Madbull PWS rail on a Marui Recoil Shock for a friend. This is how you do it if you happen to be a qualified CNC Programmer and Operator. It’s great to be in a position to showcase the talent we have in the community and thanks go to Elliot for collaborating on this post.
1. Disassembled the scar to take measurements of the stock parts compared to the new madbull parts which required modification.
2. After I figured out what to do I gathered all necessary tools to complete the job they were:
4mm End Mill
M6x1.0mm tap + tap wrench
5mm HSS drill
6mm HSS drill
2 M5x0.8mm cap head screws
1 M6x1.0mm countersunk screw
3. After all tools were collected I set the vertical milling machine up with a machine vice and used parallels to sit the job straight.
4. I began to mill the piece either side so that the bottom scar rail could slot onto it.
5. After that I had to tap the existing 5mm hole with an M6 tap to create the thread.
6. Both the SCAR body and rails had to be drilled out to 5mm for clearance. This has to be done due to the stock front block having M4 tapped holes whereas the Madbull block has M5. The existing hole on front of the front rail needed to drilled to 6mm clearance so that the new countersunk screw could pass through.
7. The two cap head screws needed to fit in the existing counterbore of the side rails. I could not mod the rails themselves as they are not as sacrificial as screws are. The M5 heads are bigger than M4 which is why they needed turning down to 7mm.
8. After this had all been done, I deburred my work and started to put the pieces together.
9. I made sure everything was done up but not tightened up too much, as it’s only aluminium (which is a soft metal). The pieces slotted together beautifully, as if the rail had been made to fit.
It now sits on there very securely with no wobble what so ever.
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