Opinions on Remington conversion

[Tubac]

I have an original Remington New Army conversion that has lost it's collectable value.
It's been buffed and reblued, a non factory firing pin has been added, the hammer milled down to shoot centre fire rather than rimfire, and the barrel is cracked.
Would it be possible to get the barrel sleeved? Or would it be best to replace it, I have a NMA parts gun with a good barrel.
thankd for your help.
Jerry