well old ed landers says to tap the barrel with a brass rod to see if it rings like a bell to check for lose ribs.
I hang the barrels by the hook from the forefinger of my left hand. I tap the ribs (top and bottom) about every 2" or 3" and note any dead spots. I look for signs of corrosion or gaps in any dead spots. There is always a dead spot by the loop and the hook.
I don't like the case coloring Ed Good has Ed Landers do to some of the actions of the doubles he buys and then sells. He bought them and they are his to with do as he pleases. But I think it diminishes the guns and I do not enjoy Ed Good's posts here nor do I find them helpful nor do they add to my knowledge of or enjoyment of my hobby.
Mike