Proper cleaning methods

[roundball]

1) Steaming hot soapy water
2) Steaming hot water rinse
3) Get them bone dry with patches.
4) Let the residual heat work for a few more minutes.
5) Use sloppy wet patch of WD40 or Hoppes #9 BP PLUS;
6) Dry patch that out;
7) Repeatedly patch the bore with patches plastered with Natural Lube 1000.

Some rifles are 15+ years old now and the bores still look like new...my personal belief is that you have to be almost fanatical about achieving the 100% mark on every single millimeter of metal surface:

100% clean
100% dry
100% lubed

IMO, if we even a little careless and any step is not completed to the absolute 100% degree, a problem will begin to develop.