[Darklen]

There's 3 #1 phillips (+) screws under the handguard with nuts on the other side. Remove them and carefully slide the barrel assembly forward. Once removed, push the hopup assembly in and gently twist (can't remember which way) and the inner barrel will come out with the hop up assembly. There's a small plastic clip with three tabs on it on the bottom front of the hopup assembly, carefully pry it out and gently slide the barrel forward. If you're too rough, you can damage the hop up sleeve and/or loose the hopup bucking. Just do the reverse to reassemble.