If it still shoot great, who not just have a gunsmith shorten and thread the current barrel? As you have found out, what the barrel looks like on the inside does not always dictate how well it shoots.
If rust from touching the gun is a issue, then you can have the whole thing cerracoated after the barrel is shortened. Even if you swap to a stainless barrel, your action is still going to be blued steel.
Bookmarks