At  a gun show this weekend I thought seriously about delving in to the full auto world.  There was a guy selling MP5 stripped lowers for $550.00.  Is this reasonable?  Is there anything special I have to do besides pay the $200.00 tax to own a full auto weapon?  

The lower, if I remember correctly is not the registered part. The receiver is.

A complete registered MP5, IIRC, will run in excess of $8500

MP5s are NOT the lower.  That is nothing more than the trigger group.  The part registered for FA is either 1) the upper reciever, or 2) the FA sear.

What you were looking at for that price was neither.  

A registered reciever is going for around $8,000 to 12,000 depending on condition and options.  

MP5s built on an autosear go for about $7000 to 9,000.  

You can buy the sear alone with good ones for about $4500-5000.  Install them with a few mods to a HK91, 93, 94 for FA in multiple weapons.

If this is your first FA, I would buy an assembled functional weapon that is ALREADY on a Form 3 or Form 4 with ATF.  Go to the forums at www.subguns.com.  This is the penultimate FA website.

It was probably one of the SW-5 receivers.  FAC sells them for around $450-$500, I think.

Rocko