Silver Paste, Dielectric grease, Noalox

[rodeo302]

I use a dielectric grease on my threads of my mutant it fits make it hit better and the threads are smoother but I can't tell you about the copper since mine is stainless.

 

[JeremyR]

I use noalox on my stainless telescopic mod, sigelie v3, and it works very well at improving conductivity and also inhibits corrosion. Actually you will have issues with the negative connection through the threads on the v3 if you don't use it. It's also used on copper telephone connections/ wires to prevent oxidation/corrosion.