Next we going to take a part our inner barel and hop up KSC M4A1 GBBR.
First remove 2 bolt which tight inner barel inside outer barrel. See 2 red arrow.
After you take out inner barrel, rotate hop up house in the direction of green arrows. Turn it very carefuly. until you see a small iron balls, beware falling!
See, this is tiny ball.
Place it in save container.
Now, remove part mark with green yellow, after securing tiny ball, pull hopup house.
Now, just pull out hop up rubber and the rest of part will fall off.
Here they are. Inner barrel, hop up house, hop up rubber.