I have nylon and metal M4s, what’s the way to extend the barrel to full lenght on either…?
Is there a kit or parts available somewhere…?
1 Like
Bit of an involved process depending upon how much longer you want the barrels.
Will need to work out inner barrel length first, along with how much inner barrel you want exposed for accessories such as hopups/flash hiders.
CYMA handguards/inner outer barrels/barrel nuts and locking mechanisms are all designed specifically for that combination to all fit together firmly.
Will be looking to find the appropriate length/design handguard to suit, along with outer barrel, barrel nut/t-piece adaptor etc to suit whichever handguard you choose.
Those clamp on type ones like in your pic are the easiest way to go 
All my gear came from Australian and overseas suppliers, which is just a matter of researching the internet until you find what suits your build.
Not as hard as it sounds, but not as simple either! 
Do you just want to extend the outer barrel or run a longer handguard?
I just use an XM-177 moderator on my CYMA M4 to give it the longer barrel look. Same blaster as your two.
Fits over an 11mm hop up, so swapping between short and long means just screwing off the moderator and screwing on a flash hider… no inner barrel swapping, same hop up, much easier.
Other than that, pretty much what Doc says… if you don’t like the moderator look you can always screw a short outer barrel extension onto the existing outer, readily available on ebay… but they don’t fit over a hop up so you’d need to fit a longer inner barrel to suit.
Or you can replace the whole outer barrel with a longer one. 
1 Like
Something like this, then add a longer inner barrel, and change to a full cylinder of you want to do it all properly… Of course you can just use the barrel extension and it will work.
More like this…length wise…
So you want to put on a longer handguard.
Plenty of options… screw off the delta ring and screw on the longer handguard of your choice with an inner and outer barrel length to suit. 
1 Like
If you stick a suppressor on like the one you pictured, that will gain you outer barrel length, then find the right handguard to go over the suppressor as you have pictured and you shouldn’t have to muck with anything else. Suppressor usually around 120-150mm long so add a bit of length and look cool.
Maybe if that satisfies your wants