I must just be lucky. Only double I've ever shot something loose on was a 12 bore Flues that as a young man (many years ago) I pounded with pigeon loads of 1-1/4 oz. and Alcan #5 powder. The rib extension loosened in its place between the breeches. Other than that I have an 80 year old Nitro Special 20 bore that's sound as a bell. I treat it gently for sure with more concern for the old wood than any mechanical areas. Have a few other Nitros (two 16's) made in 1924 and 1934. The toughest guns I've ever had were the old Stevens (Chickopee Falls guns) 5100 and a Fox Model B from Utica Savage's first year of production. It even has a serial #! Maybe not the prettiest guns but sure damned good tough old girls. Chuck from Torrence had a wonderful tutorial on relaying ribs. He is some great guy! One of my favorite posters along with Ted. Chopperlump