I have a colt 7.62x39 upper with barrel marked c mp 7.62x39 1/12 H Bar. What do i need to do to convert this to .223? I believe it is preban.Any help is appreciated

Just pull the barrel off the upper and replace it with a 5.56 barrel.  If you also have the 7.62 bolt in it, you'll have to swap the bolt over too, but the bolt carrier assy is interchangable.[:D]

There are no pre-ban uppers, only rifles or lowers.  

Your best solution is to swap the entire upper receiver, I'm sure there are folks who'd love a 7.62x39 marked barrel and upper.  Be sure you don't create an illegal semiautomatic assault weapon if this rifle isn't a legal one.

-- Chuck

Why not just have a complete 223 upper? swap uppers, all done... 7.62 on 1 day, 223 the next.

Don't forget the magazine for 223/556.

where is the best place to pick up a new upper receiver asembly?

www.model1sales.com   www.jtdistributing.com

I would go with a Bushmaster complete upper preban assembly (flash suppressor, bayonet lug):

[url]http://www.bushmaster.com/shopping/uppers/pre-ban/Default.asp[/url]

Just make sure your lower (Colt? Bushmaster? Olympic? PWA?) is indeed a preban (check the serial number), and that it was a complete rifle prior to the ban.

If you have a Colt lower, then you might want a Colt upper receiver group, but those get pretty pricey.  Specialized Armament Warehouse (SAW) has those:

[url]http://www.sawlesales.com/[/url]

Post in the Wanted to Trade in EE forums. Someone will definately take you up on a swap in no time at all.