I've only taken a couple apart. There's some brain dumps and notes in the reviews section. Search and read those.
- the blow back design is technically quite good in that there seems to be little to no additional additional stress put on other parts (i.e. it probably won't mangle itself to death)
- basically a piggy back piston that moves a tin dustcover back and forth.
- very weak action...kind of annoying after the first minute or so
- proprietary mechbox shell, cylinder, dustcover and obviously piggy back part...the rest of the internals looked "sportline-ish"...mid to low end. 1 rifle had a very badly moulded cylinder head...maybe a 1 off mistake, don't know.
Search the other threads...there's lots written up about them.