For Cobray M/11 owners (not PM/11) you likely already know this, but
here is a great product:
FTF Industries: M-11/9 Thread Protector 3/4x10 tpi
For only $10 (+$5-shipping), it screws on, just solder. tack-weld, or whatever so it is on "for good," and you no longer have a threaded...