Originally Posted by ILLusion
If you want to get an M4 GBB, building (or buying a pre-built one) that is at skirmishing quality plus 5 mags is a HUGE investment. You are easily looking at around $2500+ just to get started, and that's before you've added on any real extras to customize the look of the piece.
But besides that, the blowback features of GBB M4s is FUN AS HELL! You can not beat the experience.
G&P WOC is probably the easiest way of getting something skirmish-able for the WA platform, or a WE M4. But you are looking at expensive mags, and you are going to adopt a totally different style of playing...