Whilst it is gorgeous externally its practically zero use to skirmish with. The green gas mags are underpowered and leak like a sieve. The Co2 mags make the gun way too hot to be legal at any field you may play on. This is why most WW2 airsoft players have gone with the PPS Kar98k or a springer built off of a VSR10. Its superbly built and more importantly has an inbuilt NPAS in the bolt to allow you to adjust the FPS. Mine goes anywhere between 270-500 on green gas, so no need for Co2 at all.
The only issue is finding one of the buggers/and the mags. I had to make do with a Chiang Kai Shek version which is the chinese copy of the German Gewehr 28 but still very visually similar. In fact, there is one the same on sale on this very forum currently (not mine).
In short, do not buy the G&G