Howdy.
As some of you may know, I have been in the process of converting my Firing Line AK into an AK-104. I originally had the gun built on a Chinese parts kit left over from an Inrange Krinkov build and it looked like a Vietnam war trophy. I have replaced the old Norinco wood with a new set of wood from Global and replaced the Norinco barrel with a new Poly Tech barrel. The barrel has been chopped to 13 1/4" and I have soldered a 922r Krinkov brake in place. I also made a spacer to help fill the gap between the front sight and muzzle brake that doesn't exhist on the real AK-104 and it looks okay. If I ever build another -104 I think I'll see about cutting a Krinkov brake in half and welding a spacer in the brake itself so that it'll butt up against the gas block and still give me a legal barrel length. The gas port in the barrel is drilled at 1/8" and it is headspaced off a "GO" gauge from Brownell's.
The gun functions perfectly and shoots alright. I'm getting 4-5" groups at 100 yards with Wolf ammo. All that's left to do is attach a scope rail and refinish it with Brownell's baking laquer (as you can tell, I like Brownell's!).
Here's a link to some pics.
http://www.printroom.com/ViewAlbum.asp?userid=Tokarev&album_id=158414