Tim Hellsten basically here is a how to change your barrel
CAUTION CAUTION
work over a towel or a mat on a table there are lots of small parts that can and will spring forth and fall out you need them all there are no spare parts in the end of this....
NOTE you don't have to remove every allen bolt from the top rail just to change the inner barrel and hop up rubber.
NOTE if you do remove all the rails then WATCH there is a tiny spring and tiny brass nub thing under the rail.. this nubby and spring provides the clickey resistance you get in the hop dial...
NOTE keep track of what Allen bolt went were on the top rail if you mix them up and put longer ones in behind the hop toward the back of the gun then it will not cock and will not fire.....
1. Remove the 2 Allen screws after the hop up adjustment (toward the front of the rifle) Loosen the one directly before the hop up and remove the one that couples the 2 parts of the rail. You can leave the vack rail on If you remove it heed the earning about the spring and metal nub they will take flight
2. Remove the far back allen bolt NOTE there is a lock washer keep that don't loose it
3. flip the gun over and remove the bottom allen bolt in front of the magwell
4. carefully push up and forward a bit on the trigger guard and the whole assembly will come out leaving you with 2 parts
a. the body
b. the mechanism and barrel
NOTE there are pins in the trigger assembly they will probably just fall out... keep track of them you need them all
5. you will see a silver part on the front of the bolt housing with 2 allen bolts in it... this holds your outer barrel on
6. remove those too bolts and seperate your outer from the bolt housing
you will now see your inner (if stock) - some crappy little aluminum part and a joiner part then the brass tiny inner
NOTE. There is a joiner part that joins the inner barrel to an extension. Sometimes the joiner part fits tight inside the outer barrel. Take a rod and gently tap the joiner part out of the outer barrel It is tapered with the centre thicker then the edges It needs to tap out straight or it will get caught at the end of the barrel where there is a big slot Just be careful
Toss all that crap (so i lied there are spare parts)
7. slide out the inner and hop up assembly
8. undo the threaded retainer nut on the end of the hop up housing and then remove the barrel and hop up rubber from the hop up housing.
9. remove the hop up rubber and change barrels
10. reverse what you did to take it apart and boom new gun
3 spare parts. (assuming stock)
a. 1 mini inner barrel
b. 1 metal barrel joiner thingey
c. 1 aluminum extension part
that is it
here is a video
NPAS KC-02 / Full KC-02 Disassembly ! - YouTube