Chemical removal of cupro-nickel fouling from rifle bores is described. Method quoted from U.S. Army publication of the World War I period involves preparation of cleaning solution by dissolving 60 grains of ammonium persulfate in 4 ounces of water then adding 6 ounces of 28% ammonia. The solution should be stored in a tightly corked bottle. For use, a small quantity of the solution is swabbed into the bore, followed by a sal soda solution. If allowed to dry on steel, attack and damage can be expected. -- AATA