GHK G5 Foldable stock adaptor

Boost Me

This is a complete replacement stock for the GHK G5 airsoft rifle. It is designed to be lightweight and to lock in both the extended and collapsed positions

Hardware required:
4mm x 25mm steel pin
2 x M3x16mm Countersinks
2 x M3x18mm Countersinks
6.5mm OD (MAX) x 13.5mm (MAX SOLID HEIGHT) spring. IMPORTANT: use the strongest spring available to you for this! I originally wanted to use pen springs for this design but quickly found that the stronger the spring, the more reliable then mechanism was

All parts are already oriented correctly

Post Processing instructions:

Stock Catch. PLA
Clear any support you have for the overhang and square hole

MCX Stock Adaptor. PLA
Clear off the support. Drill the 2 through holes that line up with each other using a 4mm drill bit

MCX Catch. PLA
Clear any support you have for the overhang and the spring hole. Use a 4.2mm drill bit to drill out the through-hole

MCX Stock. PLA
Clear off the support. The 2 holes on the butt-end of the stock need drilling with a 4.2mm drill bit then tapping to M5. Main hinge pin hole may need drilling out with 6mm drill bit.

MCX Stock (1). PLA
Clear off any support. The 2 holes on the butt-end of the stock need drilling with a 4.2mm drill bit then tapping to M5. All 4 small holes will need to be drilled with a 2.5mm drill bit, then tapped with an M3 tap.

Butt. TPU
Print in TPU with no supports

Assembly method:

Step 1.
Remove the old stock catch. This is the one by the ejection port that holds the stock in the folded position. To do this you will need to use a 3mm allen key. Simply undo this screw and set to one side, don’t lose this as you will need it to reattach the new catch. The old catch is most likely going to still be firmly attached, as from factory a small amount of glue is applied to these parts. Use a pair of pliers to gently wiggle and pull the old catch off and it should come free. Once this is done, clean up and excess glue and simply screw “Stock catch” in its place. See photo for new catch in place.

Step 2.
Remove the old stock. Firstly you will need to remove the small circlip holding the stock hinge pin in place, this is found on the underside of the pin. Be careful not to lose or damage this as you will need it later for the reassembly, however if you do you can buy replacements on websites such as eBay; https://www.ebay.co.uk/itm/144556706094, the size of these being 3.2mm.
Remove the stock hinge pin and the old stock should fall freely off

Step 3.
Assembling the stock adaptor. Take the parts “MCX Stock Adaptor” and “MCX Catch”. You will also need the 4mm x 25mm pin and the spring. Place the spring into the recessed holes in both printed parts, push together until the smaller holes all line up, then push the 4mm pin through both printed parts, locking them together. The “MCX Catch” should move freely, with the spring returning it to the same position each time.

Step 4.
Assembling the body of the stock. Take “MCX Stock 1” and “MCX Stock 2” and "Butt", along with 2 x M3x16mm Countersinks, and 2 x M3x18mm Countersinks. Place the 2 printed parts over each other with the large flats meeting in the middle, with the butt between the 2 and the far end. The butt should slide onto the pins sticking out of the two stock halves. Add some superglue onto the flats of the stock halves to help bond the 2 together. Before the glue sets add the 4 bolts. The 2 16mm long bolts go at the butt end, the 2 18mm go at the hinge end. Tighten all bolts down and let the glue cure

Step 5.
Final assembly of the stock upgrade. Take the sub-assembly containing “MCX Stock Adaptor” and attach it to the rear of your G5. You will need to hook the tab into the hole, and give it a bit of pressure until it snaps into place, with the vertical holes lining up with the G5’s vertical hinge holes.
Place the stock assembly so that the main hinge hole lines up with the G5’s vertical hinge holes, it should be nestled inside of the “MCX Stock Adaptor” assembly. Take the original G5 hinge pin and puah it through from the top side of the gun, making sure it sits fully down with the top face flush to the top of the gun, then, reattach the hinge pin retaining circlip.
Give the stock a few goes to make sure everything is working as it should

Enjoy!