There was a fellow in Canadaicon who had a quantity of the galvanized steel funnels used by Britishicon troops to clean their rifles with boiling water. From what I gather, one of these funnels was issued to each squad, and after brewing up their tea, the men would use the funnel to pour a pint or so of boiling water down the bore, and then use their pull-through to run an oiled patch through the bore.
I bought one of the funnels several years ago, and it works great. When I go to shoot my No.4, I take a quart-size thermos bottle full of hot water with me to the range, and after shooting, use the funnel to pour the hot water down the bore. By the time I get home, the barrel has cooled off a bit, and I run a patch wet with Hoppe's Number 9 through it, followed by one or two dry patches, and I'm all done. Elapsed time, maybe 5 minutes.