How many rounds you recon have gone through it? Also were they hand loads or factory, and if they're hand loads were they hot?
The problem with a Swift or any really overbore cartridge is they can burn the throat out if you shoot a lot of hot ammo in them or also if you shoot them til the barrel is real hot. You should give a Swift time to cool down when it begins to get hot.
Like was said, if the barrel is shot, you will be doing good to get $300 for it. If it's still shooting real good, maybe 450, possibly $500 depending on appearance. Like was said, sell the scope separately. If not you'll get hafl price for it all. Or keep the scope for later use.