Anyone familiar with the Maruzen MP5K GBB? The Version I have at the house has a silencer with an extended barrel running the length of it. The inner barrels just but up against each other. when the silencer is threaded on it increases the overall barrel length about 5 inches. Of course this also negates any actual silencing of the gun. You would also have to make sure the barrels line up so there is no obstruction.
Just a thought...
