I don't know if you guys have tired these two products, but they are "super" cleaners:
1) Bore Tech - Eliminator (very fast copper remover - no ammonia)
2) Slip 2000* - Carbon Cutter (Non-Toxic / removes only carbon)
I have been using these of lately and they work very well, so well in fact, that I don't use Montana Extreme, Butch's Bore Shine, Barnes or Shooters Choice anymore.
*Slip 2000 was used on a badly fouled spark plug, I let the plug soak in the solution for 10 minutes. Removed plug and no carbon was present on the plug!