Don't involve me on this one Pete, I prefer caustics and abrasives.
Give the bore a good scrub with Drain Cleaner(fast, as the caustic eats the cloth) followed by gear oil and sand mix.
For the timber, a good lathering of Black paint, applied with a coarse brush(shades of India)if it was good enough for the metal, should be good for wood too.
If you don't bother wiping out before the first shot, you can always locate your first shot on the target, a nice oily hole that a patch won't stick to.(remember to wear safety glasses though, the sand and oil make for smeary vision for awhile.)
P.S Rebarrel every week.