You haven't mentioned what product you are using to get rid of the copper. What you may be experiencing is that you THINK you have all the copper out of the barrel....but in fact, you don't. So, when you shoot the next 10, 20, or 30 rounds what you are getting is these bullets are simply piling up more copper on existing copper that's still in there.

So...the product that your using isn't really removing all the copper. So....if you haven't tried "Wipe-Out", then that's what you need to try. http://www.midwayusa.com/viewProduct...tNumber=784639 If you read some of the reviews on this, the guys who have looked in their bores with bore scopes tell the real story.

I have one gun that will copper up real fast if I don't use wipe out and the groups will open up fast.

Try it...what do you have to lose?