Could you link the source of PLA switching from 12.7x108 to 12.7x99(50 BMG)? Are we talking about export rifle or what PLA uses? I understand why you don't want the rimmed 7.62x54 but it makes less sense for 12.7mm.The PLA has previously showed in a museum about their new weapons, three bolt action rifles, one in 7.62x51, other in .50 BMG or 12.7, and the other in 8.6
8.6 is .338 in another denomination. BTW, one way to tell the two machine guns apart, is that the GPMG has an beefier looking stock end.