I was under the impression that you could put a PREBAN upper on a POSTBAN lower.  I received this impression from talking to a few gun dealers at various gun shows.

Well, I read that you can only have '2 evils' on the weapon.  The 'evils' consist of:

-Pistol Grip
-Detachable Magazine
-Collapsing/Folding Stock
-Threaded Muzzle/Flash Surpressor
-Grenade Launcher
-Bayonet lug

Well, all Postban AR's have 2 of these 'evils'.  A pistol grip & detachable magazine.  So, therefore it would be illegal to put a preban upper on this postban lower correct? Most preban uppers have either a threaded/flash surpressor, or bayonet lug.

Can someone confirm this?  I thought you could, due to the 'PREBAN' upper being 'grandfathered' into the claus.

Can someone please clarify this?

Thanks,

Actually, it's a detachable magazine and ONE of those features - not any two of the features.  No detachable mag, and the rifle can have any features you like.  Detachable mag, and you get ONE frome the list of:
1) pistol grip
2) collapsing/folding stock
3) flash suppressor or threaded muzzle for flash suppressor
4) grenade launcher
5) bayonet lug

Physically a preban configured upper will fit on a post-ban lower, but you cannot legally assemble one that way if the lower can accept a detachable magazine and has a pistol grip.

But you can modify a pre-ban upper to remove the "evil" features and then legally attach it to your post-ban rifle.

The LOWER was "grandfathered" not the upper.  Lower receivers made into complete firearms before the band can have the evil features.  An upper has no serial number and is just a part in itself.  

hope this helps..and if I missed anything someone please help me.

medcop

That's the crux of your problem.  Info you got was bogus.  See above for the truth.

-hanko

no preban uppers on a post ban lowers, your post ban AR has a pistol grip and detach mag, you cant have any more evil features. I guess if the preban upper didnt have a bayo lug, flash hider or threaded barrel, it would be indistinguishable, from a post ban upper, but if thats the case you might as well get a post ban upper