M4 metal build, APS gearbox

Hi guys,

I’m trying to build my new gel blaster with mostly metal parts. I started with a Gen9 and basically have nothing left after deciding to up upgrade the hand guard to metal, I’m sure others have been caught up in this :wink:
I have a metal m4 receiver and ABS gearbox. I’m confused about what mags, t peice, mag block (wells or Gen8/9), BD556?
Basically since I’m building from scratch should I go the Wells or Gen8/9 route or any other alternative.


Welcome Brad. When it comes to inserting metal things into an M4, there isn’t much @Rowan_Ralph hasn’t done.

So how do I get in touch with this mythical beast you call @Rowan_Ralph ?

You rang Brad lol.

What are you chasing out of your blaster?


Hi @Rowan_Ralph, did I capture the mythical one;-)
I have a metal m4 receiver and an outer barrel which I think takes gen 9 and maybe some other types of t peices. I want to use a APS gear box. I have already bought the mag contact kit for the gen 8/9. Basically I need to know what mag will fit in a metal M4 and what t- peice and outer barrel coupling to take the t - peice.
Thanks mate

i am currently doing a build like this as well not sure when i get some parts in i will help if i can see these links it may help you
for T piece

mag terminal block

hope that helps but if any one has done a build like this let us know


Has anybody out there had issues with their metal gearbox getting hot and hoe did you fix it?

If there is heat it’s from friction. I’d be checking your shims/ bushings and the the AOE of all the things.

Its been apart and back together several times do you think it could possibly be a problem with the metal housing itself. Maybe a quality control issue. Is this something you have come across?

have you lived that baby up so all the parts of the gearbox shell that make contact with any moving parts are lined up. I’d recommend superlube. . https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com.au%2Fulk%2Fitm%2F113103083962

I use that on my piston rail, gears, bearings and just silicone oil on the piston oring

Hi Brad_May,

That 's very awesome, I am very interesting what you are doing… Do you have whatsapp or Facebook ?

@Brad_May, can I ask what metal reciever and barrel youre using in this build?
I’ve been trying to find these.

I second the metal reciever. Its pretty much the only plastic left in my build.

Mates just go to wish.com or alliexpress. I got mine from wish for $115 delivered.

From what iv looked at, They only make Gen 8 M4A1 Metal gearbox shell.

So you say you started out with a Gen9 mostly, So what sorta gearbox/shell is it please, Iv looked everyware for a Gen9 Metal gearbox or shell, Hmmm, And the only thing that comes close was a standard Airsoft M4A1 gearbox that was a complete metal build.

Im keen to know what parts and the like you have used in your Gen9 build, Because I have a simular build in the works.

Sorry mate, I bought a gen 9 and I don’t think I have used a single gen 9 part in my upgrade. Metal M4 reeiver which you can get from wish.com or go diretly to the shop asiaairsoft. My gearbox is a APS metal version. Still trying to get this thing working so don’t use me as resource. It’s the t piece and the barrel connection which is the biggest issue.

check out the version 3 SHS m4 hopups their for Airsoft too

Mr.milkman, I’m just building a gel blaster not an airsoft so hopups won’t work as a t piece.
It would be nice but big brother has other ideas here in QLD.

23 posts were split to a new topic: Sourcing an APS gearbox