KWA M4A1 hopup/Barrel
 

So I went to upgrade my gun recently, and found that my upgraded barrel is larger than the KWA hop-up chamber. The barrel simply won't fit into the chamber with the hop-up rubber on. looking at the stock barren and my upgrade barrel side by side reveals a visible difference in size, not much, but it's there. Also the barrel I tried to install is a very tight fit in the outer barrel itself. so it's not just the hop-up rubber being too big.

my questions are these.

What barrels will fit the stock KWA hopup?
or
What hop-up units are compatible with the KWA gearbox since the air seal nozzle has a notch in it that fits into the KWA hop-up chamber?

Ive also heard standard TM airseal nozzles don't work with the KWA gearbox.. can anyone clarify this?

PS: does anyone know if D-boys m16 mags will fit in the KWA? I need a definite yes or no on this. Thanks!

what kind of barral you put in there?

i replaced my stock inner with a madbull and it works.

humm..

try lubeing the rubber when you slide it on.

Not sure what brand it is, Bought it from a guy here in town. I know it's a brass barrel. Like I said It's literally impossible to put the barrel in the chamber lube or not, if I force it it will shred my hopup, then I'm screwed.

Any barrels with fit inside a KWA hop up, all inner barrels have the same outer diameter, so why wouldn't all of them fit?

though prometheus barrels seem to be fatter by a teeny bit, and the KWA outer barrel is very tight on the inside(to reduce inner barrel wobble for better accuracy), so Promy barrels MIGHT not fit inside, never tried it myself.

There are NO compatible hop up unit with the KWA one, unfortunately.

and yes, dboys mags fit, but i dont gurantee feeding

Thank you Skladfin!

My barrel is likely a promethius then. My stock barrel pops right back into the hop chamber And doesn't feel sloppy by any means. It also fits nicely into the outer barrel where my upgraded barrel hardly fits and is almost wedged in.

Would you happen to know if i can use an aftermarket hop chamber with another airseal nozzle? I'd like to confirm if the rumours about other airseal nozzles not working is true.

yup, you can use aftermarket hop chamber with aftermarket airseal nozzle.

I tried a couple combinations

TM hop up unit + Modify nozzle

TM hop up unit + Dboys nozzle

there were some airseal problems with the modify one, I was losing close to 100FPS, Dboys one seemed to work fine though.