T.N.T. Studios APS-X Hop-Up System Barrel and Bucking Set for KJW KC-02 Series Gas Blowback Rifles (Length: 510mm)

"Got the 380mm barrel and it comes right to the end of the thread adapter.

Raised fps by about 20fps. from ~440fps w/ .2s to 460fps w/ .2s. Otherwise completely stock.

Went from having trouble hopping .32g bbs to hopping .4s easily. I'm sure I can hop .46s now, but haven't tested it.

Accuracy increased significantly. Haven't done any testing on paper or anything but it's a noticeable change.

The biggest problem is that the bucking is an absolute pain to install. Had to put the bucking in the back of the hop up then put the barrel in and get it lined up.

"pros:
Only kc02 inner barrel and bucking that I could find that were made to fit the kc02 in its stock form.
It was able to hop bbs from .25 to .36 , I did not try heavier.
Cons:
Bbs of pretty much any weight still had inconsistent “fliers” off to the sides and straight up every few shots.
Not very accurate or consistent from shot to shot.
Bucking was A pain in the a## to install in the hop up unit.
Overall I feel like it’s okay if you’re on a budget and you’re okay with having some fliers. it will give you the hop that the kc02 lacks although sporadic. I recommend the rogueworx genesis kit, I’ve recently installed it and I’m seeing remarkably better results.