Ordinarily, after firing a barrel in good condition, the metal fouling is so slight as to be hardly perceptible, and is easily removed by solvents.
However, due to the accumulation of metal fouling, pitting (little hollows in the metal) or the presence of dust, or other abrasives (substances that cause the metal to wear away by rubbing), the fouling may occur in clearly visible flakes or patches and be much more difficult to remove.
[1327]. How to remove metal fouling. After scrubbing out the bore with the soda solution, plug it from the breech with a cork at the front end of the chamber or where the rifling begins.
Slip one of the 2-inch sections of rubber hose over the muzzle down to the sight and fill with the standard Ordnance Department solution to at least one-half inch above the muzzle of the barrel.
Let it stand for 30 minutes, then pour out the solution, remove the hose and breech plug, and swab out thoroughly with soda solution to neutralize and remove all trace of ammonia and powder fouling.
Wipe the barrel clean, dry, and oil.
With few exceptions, one application is sufficient, but if all fouling is not removed, repeat the operation.
Hoppe's Nitro Solvent No. 9 will accomplish the same result even better and quicker and with much less labor.
[1328]. How to proceed in cleaning the bore.
To clean the bore after firing, proceed as follows: