How is the .303 you are finding for hangfires?
The silver looking jacket material is cupro-nickel and the source of the great lumpy looking, accuracy destroying, fouling common in early smokeless guns. The "Ordnance Department Metal Fouling Solution" , commonly known as "Ammonia Dope," was the answer, sort-of, when the problem arose in the US Army.
Cupro-nickel was fine in the Krag but the increased velocity of the .30-06 cartridge the fouling quickly built up to problem levels. The dope would dissolve the metal fouling alright, but it was tricky to use. The "dope" was poured into a rifle barrel with a "corked chamber". A piece of rubber tubing was placed over the muzzle to allow the dope to cover the muzzle and prevent any air getting to any metal exposed to the dope. Any contact with air would ruin the barrel within a few minutes. Needless to say, Ammonia Dope was not exactly a welcome solution to
the problem, but came under the heading of "what price accuracy". If the chamber plug became dislodged while the solution was in the bore, the stuff would run down into the receiver and cause extreme rusting wherever it touched the metal. At best the dope was a nuisance and at worst, a disaster. The formula for the dope for those of you who are curious was:
- Ammonia Persulphate 1 ounce
- Ammonia Carbonate 200 grains
- Stronger Ammonia Water (28%) 6 ounces
- Water 4 ounces
The solution had to be made up fresh for each use. If the dope became "stale" it became corrosive to the barrel. After a 20-minute treatment, the solution had to be immediately poured from the bore. The bore was then dried and oiled. This treatment dissolved the metal fouling and left the bore pristine for further firing. Needless to say, the troops (and competition rifle shooters) looked for alternative methods of reducing the irritating cupro-nickel fouling. The British used a cleaner called Motty Paste which was a form of jeweler's rouge which had to be used along with a lot of elbow grease to scrub it out.
Gilding metal proved to be the eventual answer.