Airsoft Atlanta got a barrel extension for AKs from Lancer Tactical... "Lancer Tactical Barrel Extension PBS-1 AK Faux Suppressor Black.  Uses 14mm CCW threads.  Looks great on the airsoft M4 or any other 14mm CCW threaded gun. Looks good on all types of guns.  Metal aluminum construction and high quality.  This PBD-1 is a beast!  Looks excellent on AK rifles.

For airsoft use only - does not actually suppress or dampen the sound.  You can use this to extend your inner barrel through."