Rifle copper filing removal with Breakthrough copper solvent

This is a used rifle a friend bought. It wouldn't group. So I bought a 12 dollar endoscope and found copper fouling. I used Breakthrough copper solvent on it and seems to work pretty well. Time to test it out again to see if accuracy improved. Codys .270

This video is not affiliated with nor do I make a red cent from this product.
( Breakthrough) I at this time do not endorse it nor decline that it does work. Unless they want to send me some then well talk. LOL