I am currently working on a 50mm diameter silencer made out of a carbon tube. The total lengch can be chosen by yourself. Mine is ~250mm long.
The inside is acustic foam filled with different sized chambers to filter out most possible sound-frequencies. A compression chamber matched 4x the volume of a VSR barrel is the first chamber, so Influences of turbulences to the BBS flight path are minimized.
The silencer does not need a threading as is designed to be clamped on the outside of the VSR G Spec-Barrel.
Nevertheless it is not a real silencer but it looks awsome and for Airsoft/me it works great
If you are interested, PM me. Of course it is not that cheap as chinese ones...