I've been testing all of my mods for voltage drop. My methods are crude, I can't control for as many variables as Mooch can. But it gives me an idea of which mods hit the hardest.
Of course I took pics. Here is group 2, all of whom had voltage drops no higher than around 200mv, and no lower than about 100mv.
Left to right:
Slim Piece clone, brass
Tesla M2 clone, cast aluminum
Kennedy Vindicator 20700, stainless steel
Timesvape Keene mod, copper
Vindicator 21 clone, stainless steel
Tesla M6 clone, cast aluminum
A-Mod SMPL, copper