If I recall correctly Holland&Holland does not recommend using hot water for cleaning barrels. Theory is the hotter the water the quicker rust surfaces as soon as the heat dried out the bore. I've always used just tap water with no issues with a good fitting jag - I like cotton flannel patches too. I agree a swipe or two with a bristle brush assures getting BP out of the corners. This is more difficult and risky with a ML though. The best thing I was turned onto many years ago at Friendship (NMLRA) was G-96. Outstanding oil, lubricant and preservative.
