If I'm not mistaken or misunderstanding you here, the short sections of rib at the breech often include the rib extension or dolls head. As such, they are a part of the locking or breeching mechanism and subject to firing forces. It is my understanding that this area is commonly joined with braze or silver solder. A proper repair in this area will require different material and method, and more heat which would possibly melt the lower temp solder holding the long rib. I hope we can get a more learned opinion on this before you jump in with screws and J-B Weld. I think some of the guys here are confusing the lifting of a small section of the long rib with the short section that starts at the rib extension and ends usually over the chambers. Is this where the short rib is lifting...over the chambers around the forcing cone area?
