I'm thinking about buying a HK94A3 carbine and getting it registered as a SBR. Is it easier to just buy a new MP5 barrel or to get the long original 94's barrel cut down to the correct lenght? Does anybody know were I can buy the correct HK MP5 barrel? How about a good HK gunsmith, if I go the barrel cut down route. I've wanted a real MP5 for ten years and I figure this would be a cheaper route than paying $10,000+ for the classIII. Thanks for any help.

Well, I'm not completely confident in answering your question so I will refer you to the boards over at HK Pro. I know you will find you answers there.

Depends on how much you want to spend and how good you want it to look.  Obviously the cheapest route would be to have the bbl cut down.

But the best route IMHO would be to have it rebarreled with a nice 3-lugged bbl (or Navy bbl with lugs and threaded) from Murray Urbach.  When I bought my Navy bbl it was about 3 years ago, and it cost $225, so the price may have gone up, but it's still less than the $500 you'll pay for a used genuine HK bbl, and will do just as good of a job.

Of course you will have to pay to have the bbl installed and the gun refinished, but while you're at it, you could have the gun restamped 'MP5' and add the paddle mag release if you wish.  This will all cost you a bit, but if you go this route, you will have the closest copy of the real thing, minus a registered sear.

Good gunsmiths will charge a lot and will take a while, but it will be worth it in the end.  Murray Urbach, Terry Dyer (if you can get ahold of him) are the best two, but there are other good smiths out there.  

One to avoid is Jim Gravitt of Pro-tech engineering.