Mag prime isn’t a deal breaker for most.
Always handy to have some decent wire on hand and soldering supplies.
That is something I would not bother with unless you are a die hard and really want it.
But it’s up to you, we normally go robustness which the blow back and mag prime are not for high volume game days.
ETU mag prime are the go not mechanical as you tend to smash the micro switch being Rambo trying to get some 
All my experience with electric blowback has been disabling it for performance and reliability as most of my builds have requirement of improving both those categories.
Electric blowback doesn’t have a realistic amount of travel, most people wanting blowback as a feature and “realism” here just go for the gas blowback route… AEGs are always geared towards firing thousands of rounds per game and long term reliability… Here in Australia at least.
As for mag prime, I am not familiar with where the switch is and how the charging handle operates it… but you may be able to add something in to activate the switch without affecting the piston/blowback area. Could also move the switch perhaps?
Or just get a T238 basic ETU with auto prime and then you don’t have the hassle 
There’s no mosfet here lmao
sanctions = no parts/accessories/full metal builds/
a real colt carry handle is like 500 us dollars my guy
now imagine if you find some other dupe stuff for these , the problem is the price of those scammers , and other things
i was paying nearly 100$ for a metal tg arp9 gearbox that i wanted so i cancelled it… ( that gearbox had the switch burnt off )
parts are only available from broken guns
Cudos to ihobby. Ordered J12 gearbox late Tuesday night. Arrived, normal post, Thursday lunchtime. J12 functioning again. 245fps.
Steyr now has ihobby screw on hopup with flash hider. Looks lot better than suppressor on the end of barrel
here’s the mag prime btw , and the gearbox opened ( credits to grimfoxyt channel )
what should i do now ?
Thats the switch for the mag prime, there would have been a plate or something that sits in the track and pokes down behind the piston to act as the blowback, but that same plate is what the charging handle pulls on to press the mag prime switch, so if you’ve removed that plate completely there’s nothing to press the switch anymore to actively the priming.
You can grind off the tab that hits the piston to remove blowback without affecting the. Other functions but that’s a permanent fix.
now , i need a blowback plate , so what’s the compatible blowback plate for this thing ?
the blowback’s something like this snip example
Couldn’t say what plate is used for that specific model, they’re kinda all different unfortunately.
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The plate looks like sijun , will sijun fit this ? its an fjs m4 , fjs uses the same strategy as sijun according to akgelblaster , so atp i could maybe run sijun dust covers and sijun metal blowback in this thing , even the charging handles so similar
AKG would know more about those ones than me, I’d trust them if they say they’re compatible.
Charging handle are usually more specific to receivers rather than gearboxes.
You are going the wrong way about it. When you pull things like that apart always take pics on your phone as you pull bits apart.
Look at your original post Fjs m4 cqbr block 1 review
You have all the parts already and anything aftermarket will likely not fit. It is delicate to get the blow back installed. Why like I originally said we get rid of them as we do high volume and that trinketry does not hold up.
Look at the parts you hopefully have still and take better pictures and we will try help.
Something about the charging handle went bye bye, well it won’t work without that nor will it with any aftermarket one,
Recommend not cross manufacturers as they differ greatly. To save you money.
It may look the same, but is it? Have you mic’d it up?
We are not sure where you are heading, what was wrong with the OG blowback? You’ve got to be gentle with them and 2S only or they shit the bed.
Your M4 looks great. Inspired me to get out my Cyma M4 Sporter and fix the loose stock. Now thats done, ive had a few shots but then stopped and thought about the state of the gearbox lube.
I am loath to pull apart the box as I have never been able to reassemble one correctly. Is there an easy way to get some lube though to the teeth without a full disassembly?
No… not really.
It’s a good time to do your routine inspection of the gears, bearings, springs, etc anyway. Nothing lasts forever with these things, and a bit of preventitive maintenance goes a long way.
No guts, no glory… plenty of turorials on assembling a V2 box on Youtube. 
i am gentle with them , i do my best to do anything but , i wanted to do a custom gel blaster on this nylon gearbox , now i’ve decided to add a mosfet to fix that blowback problem , now i need mosfet recommendations , gun’s shell , receiver and any external thing + t-piece is going to get cnc machined in steel to match the real m4 aesthetics and a 100% volume rainbow cylinder and a new inner / outer barrel is going to get added ( edit : i will cnc also the nylon gearbox shell lol )
this is the blowback , its not that resolute ( my blowbacks completely broke , so i wanted to disable it to prevent further problems and then i screwed the mechanism up
Go on, @Maiphut
I dare ya. 
@Commando_Elitium it looks to me like you’re heading down the path of a completely custom build with parts that are 100% bespoke as they’re remade in different material to the original OEM parts.
Good luck to you if you can pull it off, and I’ll doff my hat to you if you do… and I’ve got a lifetime of toolmaking behind me.
One thing I do know is that we’re not going to be much help to you while the project is still at this concept stage. If you’re talking about the rather ambitious task of machining full metal components based on the original nylon parts, good luck, amigo.
I’m not saying you can’t do it… anything’s possible given access to the right machinery, but if I were you I’d have to ask myself “why” when the original parts are more than adequate to meet the requirements of the design brief.
I’m not sure how losing mag prime in an attempt to disable blowback requires remanufacture of parts in steel. 
well , thanks man but i don’t wanna do it a blowback again
Now i need a mosfet recommendation ( i will import some of it from china maybe ) and then I will make the thing
but the cnc will arrive next year , recently it got released from chinese customs clearance and will take time to come here ( a cnc expert from sweden is coming to iran to setup the thing , and that will take exactly 1 years or even less but my exams doesn’t let me the time it comes
well , if the cnc comes ( cause i want to get a job there and work , lmao ) i may mass produce this concept in a ultra realistic way but W/ SN Like SN0000001 or SN1038329 so i can ship it internationally and for export ( no larping but this is a 50% thing cause i’m producing them with mil-spec alloys like 4150 CMV that is used for real guns )
Have you done the courses to run a CNC Lathe 
, because I have and it it aint no weekend deal that is for sure.
Not having a go at you but you seem like you need to lower your aim a bit.
Aim for the stars, keep agl below the clouds.
It’s something way beyond me because I am a maintence Fitter and Turner, welder, machinist for decades since I was a kid and what you are talking seems to me not achievable nor worth it for the end result.
Just trying to help you not go down a big rabbit hole and end up blowing money. It’s all good, by all means please reply. Apologies if I seem angry but I am not. Brightened my morning up that is for sure
He’s 15 @Maiphut @Friendly_Fire, still at school, no job etc.
Wasn’t very popular on the Akgelblaster Discord for all sorts of talks and claims, but everyone has to have dreams in life I suppose! 