I use BreakFree CLP.
After researching the military specifications for this stuff, I was freekin' AMAZED at what it did and what it was good for.
I've never experienced a speck of after-rust from using it after hot-water washing the gun. Brushing out the bore and chambers helps, but is mostly unnessary.
US Navy SEAL teams use nothing but a hotwater rinse and CLP after prolonged seawater immersion of their weapons.
The US Navy uses it on medium to large-caliber cannon. Before CLP was specified as THE item for cannons, sodium bicarbonate wash and lots of bore punching was required to keep bores corrosion-free. Many naval cannon munitions still use black powder charge initiators, as do rocket munitions.
The US Army uses as a one-step cleaner, lubricant, and protectant for all small arms through tank cannon.
If it is "good enough for government work", it's good enough for me.