I understand the thing about the grooves missing for it locking into place but comparing the barrel against an AEG barrel it appears as if the only change is that there is that groove for the bucking to slip into and another groove for a metal "C-clip".
The closest barrel that I can compare it against is this Falcon 6.03 but I know it's not the same:
http://shop.ehobbyasia.com/upgrade-p...338-500mm.html
It appears as if the barrel is a hybrid cross between a VSR or other GBB barrel and an AEG barrel.... I'll see if I can modify it and come up with some favourable results. Basically the idea is to dremel those grooves in. Remember, it's easier to remove material than to replace it so hopefully this works out. I'll do it slowly and if it works I'll post up pics showing people how to do it.