The older one-piece-bolt barrels will not unlock in the newer frames. Remove the trigger guard too, and then from the bottom use a big screwdriver to push the bolt back into the lug. The barrel can then be lifted out, but be careful as the bolt will still be under pressure from the screwdriver.
Now order a two0piece-bolt and spring from T/C and replace the old bolt. Don't ask me how I discovered all this almost 20 years ago.....
