Great debate coming up, I can feel it. It all depends on your perspective.
To a collector, the gun fitted with the worn out but original barrel would be worth more to him than if it had a nice shiny replacement.
To a shooter, the brought back to decent shooting condition rifle with a nice shiny replacement barrel would be worth more than one that is crapped out but original..
Depends what you want to do with it. Look at it, fondle it and imagine it shooting, or, shoot it and enjoy trying to hit bulls eyes.
Two different schools of thought.
I have two old Army Jeeps, both original. One just sits in the garage with a blown engine, the other I drive with a rebuilt replacement engine and transmission.
Both basically the same model. Which do you think that I value most, and which one do you think that I would sell first?
If a rifle in service was sent to the unit armourer with a worn out barrel, what would he do?
Bit of a contentious subject.
But do try some flat based bullets. There are some available made special a wee bit oversized. Some worn barrels still shoot well, or at least well enough to have fun.
You could always keep the old barrel and include it should you decide to sell. Not a big deal, the barrels, although very tight just screw in and screw out. Easy to change with the right tools.
Now I will duck and put my helmet on.