Ok heres a questions. I'm not sure of the legality of it so if it gets locked, oh well. Someone a coupe days ago asked about a m-16 someone had taken home from vietnam and in some way it landed in someone of his friends hands. Could that person with the unreg'd full-auto m-16 replace the tigger group and bolt with a semi-auto kit and have it be legal?

Since the position of the ATF is "once a MG, allways a MG", he'll probably have to replace the receiver as well.

Right now he owns and illegal unregistered machinegun. The only way to make it legal would be to destroy the receiver. However, I believe that legislation is on the horizon that will allow veterans to register war trophies instead of having to destroy them. But, since the gun is basically stolen government property it might not make any difference either way.

The best thing to do is call up ATF and confess.
That way you don't have to worry about it anymore.

The next best thing to do would be to get rid of/destroy the M16 lower and parts and replace them with a semi auto lower and parts.

Another possibility (not necessarily the legal thing) would be to separate the upper from the lower and then strip the lower. Stash the lower away somewhere and the parts away somewhere else.  Buy a semi auto lower and build with semi auto parts.

your right about the legistlation.but from what I understand they would have to been deployed outside the states before 1968.

I am not a lawyer, but I watched Matlock a few times...

Regarding the topic of stolen property-- I believe the statute of limitations would apply for the person who "stole it".

Since your "friend" is still in posession of an unregistered machine gun, I guess he could possibly be charged with having an unregistered machine gun, and (knowingly) being in posession of stolen property, and all of this involves a firearm (to make it worse: a stolen unregistered machine gun) which could make the charges more severe.

He should do something-- at least melt down the M16 parts and receiver, or turn it in to the authorities before getting busted, since you posted this on an OPEN FORUM.

"Statute of Limitations" does not apply to stolen property, because possessing stolen items is an ongoing offense.

To illustrate this, you have a kilo of Cocaine. It was made in 1965 (as evidenced by a manufacturer's label or whatever. Let just say that everyone agrees that it was made in 1965). Your state has a 10-year statute of limitations for controlled substances felonies (including possessing cocaine). You get caught with it now. You are still guilty of possessing cocaine, because the cocaine is still cocaine regardless of when it was manufactured. If you were the one who made it back in 1965, you probably can not get dinged for making it, but you can still get convicted for possessing it.

Likewise, stolen property stays stolen forever until it is returned to its rightful owner or otherwise disposed of via a court order.

That's pretty much what I said.