so nobody gets any ideas,no I don't own any full auto stuff.I'm just curious bout them.I have checked the WWW. and I think what I'm looking at is right.The best I can figure out,it's ok to own machine gun parts,the internals of say a Thompson,50 cal BMG,Vickers ect. long as you don't have the unregistered receiver. But you can't have a drop in auto sear for an AR-15. The DIAS is the machine gun. I know we are talking about the ATF, but I can't see the logic in the thinking. It's been a while since I've seen a sales ad for a DIAS in shotgun news . But you see ads all the time for BMG rebuild kits. And saw one the other day for a Vickers. Oh well,just wondering...jwr