I had a second barrel fitted at the factory and would not do it again. At first it seems like a great deal BUT after you get a second scope, pay for shipping, insurance, the barrel and fitting it is almost worth getting a complete new rifle.
This might not be the case if you use open sights on the new barrel.
I prefer the new rifle approach as I then have a separate rifle on demand and it makes selling the rifle a lot easier etc.
Just my thoughts