I bought a bore scope a while back. Although it did seem to be an aid in telling the level of copper foul, your patches will tell you if its clean or not if using a good bore cleaner.
What a bore scope did tell me, was the reason a barrel may not shot or why a barrel may shoot good. With that said I am sure I have barrels that look like a million dollars and still my not shoot 5. moa and others that look like crap and shoot lights out.
I was working with a gun I orginally bought for the action. Decided to see if it would shoot, well it didnt. I swapped scopes, different loads but it was all over the place. Buddy of mine said you need a bore scope so I bought one. Did having a bore scope enlighten my mind. Also told me the rifle I was trying to make shoot had the throat shot out.
Another thing it I've gained from a bore scope is how good some factory barrels look. I have a 550 CZ 375 H&H that looks really good. Same for a Factory Win take off barrel a buddy of mine gave me. Both shoot really good.
Looking at the two rifles Douglas barrels I have, its pretty obvious they are not lapped, or at least look that way to me. One shoots decent, the other maybe shoots 1.5-2 inch groups. Compared to a Shilen the douglas barrels aren't even close. Some of the Shilens I looked at have not been shot so not sure of the outcome. But my guess they will shoot.
Last thing I was able to glean was the crown. Before I was looking at crowns using a light and magnifing glass, looking at a crown with a bore scope is much better picture for me.
A Wi Fi bore scope that connects to an iPad is a handy tool. Wish I would have bough one years back. Best 100 bucks I've spent on Amazon in a while.
Thanks Billy