What are the best copper and powder cleaners? I picked up a Used 270wsm and the accuracy wasn’t up to snuff. I suspected a fouled bore, well I’m on day number 4 of scrubbing and soaking with butch’s bore shine and M-pro7. Even letting it soak over night and thru the day while I’m at work! No end in sight. I was starting to wonder if the barrel was cast iron and coming off on my patches. I have finally gotten down to blue patches so I know I’m getting copper now? Any suggestions?