Typically rather than moving the rear sight back and cutting the barrel and threading, I back bore into the original bore, thread internally, then thread in an extension long enough that the 1/2X28 threads protrude from the end of the barrel enough to mount the silencer.
Not as purty as the move sight, cut barrel short, thread barrel use cut off piece of barrel to make a matching profile thread protector, but some only care about function not purty.