"Unfortunately, there were more fundamental flaws in the process with commensurate effects on longevity. Once lined, the barrels cannot be heated because it would melt the adhesive. Therefore, loose ribs or loops cannot not be repaired. Sometimes, the liners twist in the barrels. Other complaints included a rivveling effect developing in the outer skin. This has been attributed to the cooling and heating of the barrels during use and the different rates of expansion and contraction at molecular level of the three sandwiched components – the liner, the original barrel steel and the thin gap filled with adhesive."
"Barrel makers started reporting that dented barrels which had been lined were impossible to repair. The hard lining and the soft outer skin reacted differently to dent raising techniques and dents could not be raised acceptably. The result was often scrapped barrels."
Anyone who has shot a tube O/U know tubes can change the gun feel. But when you have a set of barrels which can not have dents repaired and may have rivveling or ribs impossible to relay it becomes a one way operation. It works until it does not work. Then you have a set of barrels you may not even be able to sleeve.
