The muzzle of mk2 is threaded, but 9mm doesn’t really need a flash hider. So I added a linear compensator aka noise re-direction device.
Works very well: the report becomes a lot less noticeable, especially with subsonic ammunition which doesn’t produce a secondary shockwave.
Accuracy observation: 100-147gr ammunition works well. 75gr or 158gr don’t, and neither do 50gr hypervelocity arounds. Lighter bullets show the best velocity gain, which means 100-110gr are probably optimal for the combination of accuracy, terminal effect and lighter felt recoil.