I don't know if this helps but it worked for me. I was having the same kinda problems with a brison 2.4 on my sig cap. Intermitent radio hits. I tried everything. It turned out to be the manual ign. switch i had bought. I bought a toggle switch from radio shack. It is the kind that you solder the wires onto the poles. I went with a cermark hd rx switch and it cured the problem.

I had used shrink wrap to cover any exposed wiring but i guess it wasn't good enough.