For me the peroxide is reacting to remove the surfactants in Butches Bore Shine. I picked this method up from Speedy.
I only do it because I want every last trace of everything out of there. Down to white metal clean.
I only want that so that I can dry pre-foul.
It takes anywhere from 3-8shts to burn petroleum products out of a bore, and lay a new fouling layer.
To work around this, folks choose to leave their barrels dirty. I would not do that beyond a week or two of hunting.
The reason being that carbon takes a set with time, and I doubt primer residue is 'good' for bores.
I also don't like leaving oil in bores. It is useless to prevent corrosion, and can migrate down into the chamber/action/ bedding.
So I just keep my guns clean and dry.