The twang noise when you fire your VSR based rifle has a distinct metal twaaaaang, usually caused by the metal parts vibrating together.

Theres a simple way to reduce this to just the thud of the piston hitting the cylinder head by wrapping the spring guide with some PTFE tape.

It appears how ever i may have put slightly to much on as i do encounter some slight resistance working the bolt, something that no one else has mentioned.