The only reason mechanically to remove a liner , is if the touch hole gets oversize and the accuracy begins to drop off. In years back , some guys began to use a 10 X 32 removable Allen lock screw with a hole drilled in the bottom. The idea was to make it easier to clean the rifle. Well , the constant heavy handed wrenching on the A-screw eventually ruined the threads in the barrel. That was enough reason to quit using A-screws for touch hole liners. Most m/l barrels are lead bearing steel alloy and can be soft ...............oldwood