Very tight Mega Monolithic Upper ???

[StoneTower]

You have to be careful with the heating freezing technique. I have used this method to put bearings on a shaft for a rotisserie that was for cooking 3 whole pigs/lambs at a time. Once the temperatures equalize, there is no way to remove the bearings. You may never be able to remove your barrel. You cannot heat or cool the completed part because they will both move in the same direction.