To kick off with, you will need to know precisely what the thread size of the receiver is. I wasted a lot of time trying to find this out there in internet land and never found anything that conclusive. Then you need to find someone who will do a one-off machining job for you but they will need an exact spec if you do find someone. I took the easier option above, and packed out the airsoft can with decent sound deadening material. Worked fine.