Washington State fuzz...
Because of my recent relocation, this was major concern.
The state regulation concerning unlawful firearms and parts contraband includes the phase "...or any part designed and intended solely and exclusively for use in a machine gun..."
At first blush it sounds like any 1919 parts. But thanks to the BATFE semi approval documentation, the only parts exclusive to a MG are those that apply only to the FA. That would be the un-modified trigger and the sear (oh, and that pesky FA reciever). The remainder are "designed and intended" for the approved SA. A sleazy move to stiffle kit builders, no doubt.
Still, its one of many tactics used out here spook gunowners and shooters. Most shooters are tight lipped about shooting spots on government lands. The one rifle club that I have visited has suffered, like many, encrochment with new neighbors un-freindly to shooting.
I haven't shot "Rolling Thunder" for two years.
So, I haven't heard of any legal confrontations concerning the 1919 in WA. I hope I'm not the one to experiance such an event when I do finally shoot.