for plugging the bore the hardware stores have a thing (can't think of the actual name) that is basically a rubber stopper with a bolt for a core and a metal washer on each end. Tighteneing the bolt conpresses the rubber enlarging its diameter forming a liquid proof seal.
I vouch for the Wipeout though as it is much easier. I have a rifle with a nasty bore and giving it 2 1/2hr treatment of wipeout made it shine. It is still pitted, but it got the crud out of the pits!
the blood runs free, the rain turns red, give me the wine, you keep the bread