Actualy you can not compare a sleeved gun to a gun built on a monoblock . There are many factors that have to be taken into consideration , type of lump join ,stength of braze age etc.Point is that sleeving can prolong the life of a gun for a quarter of the cost of new barrels . 40 years ago it was held that a sleeved barrel would have a life expectancy of around 20/25 years . I see guns that were sleeved in the early 60's that are still in reglar use .