TDC, light trigger pull (I don't know how to do it yet though, at least with stock assembly), and longer barrel if you want to turn it to a rifle completely.
For gas guns in general, you actually need to do adjustment too, to its spring knocker power to adjust the fps. But most of the time it is unnecessary since even with stock setting, the gas output is "overvolumed". A knock from its hammer is powerful enough for a 500mm++ inner barrel.
For gas guns in general, you actually need to do adjustment too, to its spring knocker power to adjust the fps. But most of the time it is unnecessary since even with stock setting, the gas output is "overvolumed". A knock from its hammer is powerful enough for a 500mm++ inner barrel.