RE: Which powder should I use?
It has not been mentioned yet; but Ballistol is another choice for patch lube. It can be used just as it comes from the can and also works well as a barrel preservative after cleaning. It will mix with water and as such if there is any trace of water in the barrel after cleaning when it mixes with the Ballistol it will not rust the bore. If you are not familiar with the product it is very old originally came from the German army and works on metal, wood, leather and is basically non polluting and some say you can even eat it without causing major problems. Smells somewhat like licorice. Personally I do not recommend trying to eat it (don't like licorice anyway). It is a little hard to find, but I bought mine mailorder from a Google on the internet.