Custer said:
I use 50-50 ammonia after shooting corrosive ammo. I was thinking of hydrogen peroxide as a possibility of really cleaning up an old bore.
I have a drawing of that gizmo. One of the projects I'd like to try if I ever get the time.
Very simple to make and I can describe it quickly.
Take a rod, preferably stainless steel. A car antenna works best from the junkyard or you can rip one off of a neighbor's car you don't like.
Wrap the very bottom with shrink wrap tubing and then about every 4-6 inches it should have a wrap too. That keeps it from contacting the barrel.
Get some rubber stoppers (rubber corks) for the breech end of your barrels. Plug the breach and fill with amonia.
Put the rod down the barrel and hook a positive lead to the rod. Neagative to the gun.
My Dad uses a battery charger for a car set on 6 volts or you can do 12. Some guys use 3 volts and 2 C or D batteries. If you use the the battery charger you need to check the mix more often. He goes about 5-10 minutes and empties the barrel. Black brackish crap comes running out of the barrel and it might take 4-5 cycles to get it mirror like. He used this on our Mosins which looked clean, but were not any where near clean.
I have a rod ready to go, but I have not used mine yet even though I have a battery charger.
Doing a semi-auto you will have to figure a way to pug the gas port of course.