Which hopup for upgraded Gen8?

Ok, so I’ve installed this outer barrel:

Colour: Black
Material: Alloy
Size: (L) 35cm
Female/Male End Threads: 14mm
Outer Barrel Dimension: 19mm
Inner Diameter: 9.6mm

And this inner barrel:
Colour: Black/Red
Material: Alloy metal (Inner barrel), Plastic (TPC)
Inner Diameter: 7.4mm
Size: 27.5cm, 29cm, 33.5cm, 40cm, 47.5cm

into my Gen8 M4.

I suppose the recommended DK J8S hopup won’t work now, because the barrel sizes are different.
Which hopup should I get?

So is your outer barrel(35cms) is longer than your inner (33.5cms)? I dont know any that would work with the inner not sticking out 10mm

Sweetheart hopup is prob your only choise as it fits onto the inner barrel ans is not much bigger than the outter diameter of inner barrel

The sweetheart hop up is 10mm OD and that outer barrel is 9.6 id so it won’t fit without modification.
You could cut the outer barrel a bit shorter and use any standard 9.5mm hop up or one of the screw on ones such as the DK J10

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I’d go the path of least resistance and shorten the outer barrel as Rattler suggests… or install a longer inner barrel. Then you can run any of the barrel mounted hop ups. :+1:

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I’ve bought the same 35cm outer barrel but I got a 35cm inner barrel as well under advice from a seller off eBay so does this mean the original dk-j8s hop up won’t work with a screw on end cap, or would a gen9 hop up work with this upgraded barrel and let me put a screw on end cap over the top of it?

It should be ok because the hop up on the gen 8 slide fits inside the outer barrel.
Edit… Actually if the one you used is the one above it won’t fit sorry

So yes you will need a DK J9 or J10 and they won’t be perfect because the inner barrel won’t protrude into the hop up but they do still work

Thanks and will the screw on end caps go over the hop up and if so does it matter if I use an end cap of the AUG, will it fit?

I don’t know the AUG flash hider sorry.
I fitted a DK J10 into a flash hider that slides over a 19mm barrel and spot glued it in then the entire flash hider became a screw on hop up

This was the kit I bought, the DKJ10 was a perfect fit in the flash hider and I pushed it all the way in until it was flush with the back and made sure the hop up adjustment screw was in one of the cut outs so it can be adjusted , now the flash hider is a screw on hop up, You also get a silencer that screws on to the flash hider.

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Oh yeah that looks sic, what I grouse idea thanks for your help hopefully mine comes out looking half as good as that!


Here’s the whole blaster, it started life as a Kublai MK18 K2


And with the standard butt stock


That’s beautiful bro lot of time and tlc gone into that, I sorta like the original stock on it better. I’m only new to the game I got this m4a1 gen 8.5 as my first which i’m waiting on the last of my upgrade gearbox parts and ID tight bore barrel to come in and have just started the cosmetic side of things :grin:. I have also just splurged on one of those SKD Beretta 90-TWO’s 14.8v pistols the other day. I used to hop up my RC cars but find this alot more enjoyable. Have you had much experience painting the nylon parts if so do you need a spray that lets paint stick to it

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Yeah I also like the original stock :grin:
Oh yeah your hooked mate ! You will love messing with these and putting your own stamp on them, so much you can do.
Sorry I don’t have much experience in painting nylon because I love black :rofl:
I would really like to get into hydro dipping and maybe do a realtree camo job

Hell yeah that’d look sic as. I saw a ■■■ with fishbone, switches and releases etc pretty much all the accents in dark red looked evil😈 so def reckon I’ll get into painting, I haven’t seen this hydro dipping but will def look into it I taught myself how to spray a car this is on a whole different scale with heaps more details🤔 sounds like a fun challenge especially ATM lol not much else to do but go stir crazy lol🤯


Nice sounds like you’ve got the skills and drive necessary :+1:
I here ya with regards to stir crazy, my problem is I’ve got so many blasters that I don’t need any more :blush: Well maybe one more or possibly two :rofl:
Anyway welcome mate, have a good look around the forum there is so much great info here and plenty of knowledgeable guys to help with anything you need :wink:


C’mon Rattler… you know deep down you can never have enough blasters… :joy:


Lol I don’t have to look too deep to know that :rofl:
I keep making lists of parts and then saying to myself, stop !, what the hell are you going to do with another blaster when you allready can’t use the 12 you have now, but a little voice keeps saying, why not :blush: