The way the hughs ammendment works is, the only legally transferable machine guns were those that were on the registry in 1986. The total number of those registered machine guns was 175,977. There are no more. If your gun was not on that registry when the hughs ammendment passed, the answer is no.

But… god these rules are ridiculous.

For certain guns, if you have a legally registered full auto sear (the sear in this case is the firearm), you can put that in the appropriate nfa registered firearm (think sbr), anf then it would be legal.

This is normally how you see fully automatic hk95 and mp5s and registered colt recievers put into modern ar15 platforms.

It really is a shitshow when it comes to these laws. The real answer to all your question is money. If you have the cash equivalent to a brand new vehicle just sitting around, you can have a legal full auto gun. If you dont have those funds, dont bother. You wouldnt be able to afford the ammo for a fully automatic anyways.