I have a post ban AK47 & AK74 and want to attach a basic "bird-cage" stayle muzzle brake to each one (as per BATF guidelines). I have the two MB's that are threaded and I just bought two MB adapters that attach to the barrels via 4 set pins each. Question #1: Since the outer diameter of the AK74 barrel is a bit smaller than the inner diameter of the adapter, is there a "spacer ring" or some other gap filler that I should use between the MB and adapter, or will the 4 set pins, once fully tightened, be suitable to secure the MB to the adapter? Question #2: Is there some sort of lubricant/sealant that should be spread onto the threads of the adapter and MB and set pins to prevent small open spaces in the threads that could allow gas build-up? I want to use this project as my intro to basic gunsmithing, so any and all suggestions are greatly appreciated!

When it comes to sealing seams the std slow set JB Weld is about 600+deg tough, quick set is only about 400 deg durable.
If you choose a larger dia attachment, the muzzle adaptors can be slid down to the front sight base and welded there. This leaves min damage to the actual bbl should you need to remove the attachment later.

Take a deep breath and wait 11 months before messing with muzzle devices on your AK.

The ban "will" expire. The question remains what will replace it.

CampyBob: If the bird-cage style isn't allowed, are the slant-style MB's OK? What types are allowed on post ban AK74's (I've seen several differnt styles catagorized specifically as AK74 MB's)? And if they are and are made in the US, would that count as a US part per the BATF guidelines? The 4 screws are set screws (tightened with a small Allen Wrench). Thanks very much for your help and suggestions.

Waiting 11 months for that ridiculous ban to expire sucks, but I'm thinking you may have a good suggestion there. But, as you said, "what" would replace it?? I've heard people saying that any and all AK's will soon be prohibited from importation, do you know if that's true or not?