Originally Posted by L473ncy
Note that TM, G&P, and CYMA/Echo1 M14 are TM compatible, G&G just went off and did their own thing.
Be aware that while G&P and Cyma are both version 7 design, i found the G&P to have subtle differences in the piston/spring guide assembly that made parts swapping cross compatibility a no-go. It's been a while since i looked into it, and i'm hardly a pro by any means, but when i bought a CYMA parts M14 to repair a G&P M14 DMR gearbox, it was a non-starter. One, or the other, is off-spec from TM.
It's still in pieces awaiting inspiration, for that reason.
As for the OP's original question, pestobanana is correct.