Wondering if anyone is using or have used/tested the above platforms for PCC? I am currently using a CMMG Guard 9 and it has served me well, however... I am eyeing wether to purchase a SIG MPX or a JP GMR, I prefer the bolt action of the MPX my CMMG has a radial delayed blowback system which makes it extremely soft shooting. But there's hardlyt no aftermarket support for the CMMG but I love the platform. I'm leaning heavily to the Sig MPX but why does sig have to make it a propriatary mag? smh~ Anyway, anyone care to chime in? I'm sure this topic has been covered before but I'm just being anal with my future decision...