Language is continuously in fluctuation. Dictionaries don't define our languages, they simply reflect what has become common usage. Webster's adds and changes new words and their definitions every year. The word "tweet" got a new definition added, not changed, a few yrs back. That was based on what the people were using in their vocabulary. Browsing Webster's will reveal many words with more than one definition.
They'll be those that believe that a word has only one meaning, while others will use it to describe something different. It's not law. It's whatever people come to use frequently enough that others understand them. People start using terms and words for other than their original definitions everyday. Some catch on and become common. Common useage defines a word or term.
Frankly, if you'd have asked 100 machinists that didn't know guns and gun terminology what they would call the process of cutting off barrels by the breach and boring the chambers, then soldering in some new barrels, I doubt you'd get many if any that would come up with "sleeving". I think most of that group would call what Teague is doing "sleeving" rather than "lining". But that word was already taken.

And what about those other Brit cousins that eat that haggis stuff? Yuk!
