I don't have one, but I know that what they are mostly talking about is when you have the lower disengaged from the upper, but with the front pin in.  The massive weight of that upper can break or damage your lower, if you are not carefull.

As to the legality question, you just turned a semi-auto into a single shot by adding the upper.  Nooo problem!

I MIGHT have bought one, but if I did I probably wouldnt say so. What with the future ban and the ATF readin the site and all. :)
ok, ok, ok...the tin foil hat is off.
Yeah I have one and Larry is a great guy to deal with.
The disclaimer is a basic requirement for this monster. The ONLY time you will have a problem is if mishandling it while reloading the chamber.
Remember this is a breach loading, screw bolt configuration. Th lower has to be released by it's rear pin and the bolt unscrewed. Slow? Yes but you arent paying for a bolt action either.
In this state the lower is suceptible to damage if it is twisted while still mounted on the upper. But you know what? it's no dfferent than if you did the same thing with any AR15 upper!
Dont let anyone scare you about the Alum. lower not handling the stress. I have seen NO damage to mine at all after several hundred rounds. It all has to do with the direction of recoil and the ammount felt after the monster of a brake is done with it's job. Feels like a 12 guage single shot. In fact I'm pondering some modifications to my brake for more recoil. It is a toy after all and MOST impressive to anyone that see's it or shoots it. It's as tall as I am and I usually have a line of folks wanting to try it.
I looked at it like this, I can get a lower stripped for $80. If it destroys my lower I'm only out that much and I'll sell it. I still have it and will not sell it unless it is to upgrade to another .50.
Hit me off line if you have any specific questions. I dont work for them but I will tell you like it is.
jneal

Spend an extra $700 and get a complete rifle, the .50 BFG, from Serbu.
[url]www.serbu.com[/url]

Watson's has been the one and only .50 I've ever shot and only 1rd :( but it was HELLA COOL I've been around people with .50s before and always wanted one, now I must have!

Damage to the lower is something I've thought about also but, do the math lower=hundred bucks ww50=1200 you have a 5bmg rifle for 1300 bucks. assuming you have enough money to buy the amount of cartridges or the equipment to reload them, to actually stress or break the lower whats a hundred bucks? Buy it! you know you want to, get me one too.

I don't believe there is a wood-stocked BFG, but Mark Serbu has a Aluminum/Titanium lightweight prototype that is a real eye popper.

[img]members.aol.com/markserbu/bfgcar1.jpg[/img]

You might be surprised with your FFL.  One charged me $25 to accept and transfer my .50.  I would like to get an NAA Guardian in .380, soon. I will buy it from that dealer to show my appreciation.

One day all guns may be banned, some sooner than later.  We must stand up and fight it, sooner not later.  I don't see the .50 being reclassified as a DD just yet, but you can be sure that there will be an enormous push to ban .50 AP ammo, one way or the other.
If the .50 was classified as a DD, you would be expected to [b]get[/b] your upper serialized and registered.  Or, you would have a $1300 hunk of steel under your bed, and nowhere to take it.  Also, don't think that they wouldn't look over Watson's sales records, to track down those uppers.  

[img]www.statearms.com/images/Shorty.jpg[/img]

[url]www.statearms.com[/url]

lockandload:
try this co.
New Helvetia Trade. 2215 ‘J' Street
Sacramento CA. Call 916-446-2737 or email [email protected]

Also called GFFC corp. They have stripped Oly's for $89. Shipping is $10/order

Most of my lowers are Oly's and I have never had a problem. Btw...these are forged.
jneal