The corrosive effects of shooting black powder or modern substitutes, comes from the byproduct of corrosive salts produced when the powder charge and primer are fired. These salts are deposited in the fouling and microscopic poors of the bore and if left uncleaned will attack the ferrous metal of the bore causing rust.
By chemical nature the corrosive salts are acidic on the PH scale of 0-14. Anything below PH=7 is acidic and anything above PH=7 is basic. Drinking water falls in the neutral PH range of 7.
The most common way to neutralize corrosive salts is to dissolve them in enough water, or other neutral Ph median, so they chemically breakdown and the entire solution reaches a neutral PH level of 7.
Another way to raise the PH level of acidic solutions is the use of Basic medians, like Hydroxides. Ammonia, Baking Soda (Sodium Bi-Carbonate), Soda Ash (Sodium Carbonate) and Caustic Soda's are several Hydroxides that can be found in the home or hardware store. This is why a lot of people use Windex or Ammonia based window cleaners when swabbing the bore between shots, it helps to neutralize the corrosive salts in the bore.
Murphys Oil Soap has a basic PH, higher than 7, most likely due to a Hydroxide being used in the formula. When you add the M.O.S. to your cleaning water bucket you will raise the PH of the water, which help to chemically neutralize the acidic salts in the bore in addition to the dilution method of plain water. Simply adding a few table spoons of baking soda will do the same thing if you prefer to use a detergent like dishwashing soap instead of M.O.S.
Cold vs Hot water, age old debate here and lots of opinions from all sides. Most of us use a lubricant that stays soft making loading, swabbing and cleaning easier. The lubricant is soft and coats the metal, very tiny particles of corrosive salts will penetrate the lube and enter the poors of the metal from one shot to the next. Hot water will help open these poors up allowing the salts to be chemically neutralized or diluted to a neutral PH level with a hot water only cleaning.
Peroxides in your cleaning solutions...
Peroxides are oxidizers and will promote the oxidization process of the acidic salts, this leads to rust when the salts are in contact with metals.
Most people use the 3% Hydrogen Peroxide found in the medicine chest or pharmacy. You actually have 97% water and 3% H.P. which is pretty mild but still strong enough by its self to promote the oxidization process of the acidic salts. If you doubt this, then pour some on a fresh cut and watch it bubble and fizz, this is the oxidization process in action as it reacts with the acids in the body.
Most people dilute the Hydrogen Peroxide into other medians, like Water, Murphys Oil Soap or Ammonia based window cleaners which pretty much neutralizes and kills out the peroxide, and some of the hydroxides, in the solution within a short period of time.
By mixing Hydrogen Peroxide with your Hydroxide and water based cleaning solutions you are reducing its neutralization effects to a degree. Using plain water would be cheaper, and safer to the metal, just use more of it.
If you use Window cleaners to swab between shots then DO NOT USE Vinegar based cleaners. Vinegar is nothing more than a diluted form of Acetic Acid, which is on the lower end of the PH scale and like the corrosive salts its acidic in nature. Using a Vinegar solution would just compound the problem of trying to neutralize the acidic salts in the bore.
I use Murphys Oil Soap in hot water because it both cleans and chemically neutralizes the corrosive salts at the same time. Followded by a hot water flush, drying and lube.
Regulis7