I am not looking at converting to an alternate FCG. I think one or two US made parts and the gun would be compliant. More important are the denial features to make it acceptable to the ATF. The denials needed are something to keep it from going into full auto and a something to keep the trigger pack from being exchanged for one that is unmodified. The unique think about this FCG design is that the sear and disconnector functions are achieved with one part. There is no sear to remove like in the HK trigger packs.