The tubes usually called "liners" are thin and cannot be used with high pressure cartridges. The reason is that when reaming out the original barrel enough space must be left for the solder or whatever is used to keep the liner in place. That means the liner is smaller than the barrel, so it must be able, itself, to contain the pressure, otherwise the liner will expand in an irregular manner depending on the irregularities of the solder or epoxy.
When it is desired to "line" the barrel for use with high pressure ammunition, a standard lightweight barrel is machined down so it will fit into the original barrel. Unless the original barrel was quite thick, it becomes a thin shell. But the inner barrel (some call it an "insert", reserving the term "liner" for the low pressure kind) must be thick enough to hold the pressure. Not many gunsmiths will do that work and they usually do it with many caveats and cautions.
That kind of "insert" is usually used where the rifle is a collectors item and it is desired to keep the original barrel markings.
Jim