Solitary Man, I saw this when all the powder fouling was out. In other words, I removed all the powder fouling with CR10. Dried out the bore with several patches, then put my soaked patch with CR10 thru. Unfortunately, the range officer called for a cease fire. So I couldn' t touch the gun. Then after the cease fire about 15-20 min later, I saw all this red come out of the bore. And it was rust.