Cleaning Copper Fouling from a Historic Perspective
by Kirk Lawson
In an earlier series of articles, I discussed a few historic methods of cleaning and some historic recipes, as well as some modern ones, for cleaning solutions. One historic method hailing from the U.S. Army mentioned issues with copper fouling but did not discuss it in detail.
Cleaning copper fouling then, as now, was achieved with a combination of good old "elbow grease" and a copper solvent solution. Here is one common solvent solution from Outdoor Life, Volume XLI., January, 1918, Number 1.
ARMS AND AMMUNITION QUERIES
Can you give formula for removing metal fouling from rifle barrel. My Newton smooth bore has fouled with pure copper jacket bullet. I have seen published stronger ammonia and ammonia persulphate formula, but can’t locate it in my back numbers—C. R. Danielson, San Francisco, Cal.
Answer.—The formula for removing metal fouling is as follows: Stronger ammonia, 1 fld. oz.; ammonium carbonate, 25 grs.; ammonium dichromate, 5 grs.; ammonium persulphate, 50 grs. A bite of prevention might not be amiss in this case. When you have your rifle out to shoot always look thru the barrel and see that the here is perfectly bright from one end to the other. Sometimes an oxidization will set up near the muzzle, giving the muzzle end of the bore a dirty appearance. This can be readily wiped out with a cloth rag, but if not wiped out will most certainly produce metal fouling in large quantities. Many have had trouble from shooting rifles without making sure their barrels are bright at this point—Editor. [sic]