Just a few thoughts:
---When you go to pull a ball with a ball puller, you have to get the puller well into the bullet. It usually takes me two or three tries while having the barrel clamped on a bench and me pushing like nuts and turning the ball puller.
---That barrel appears to be T\C. I'm judging that based upon the hook breach size, and the wedge key.
---The flash hole tap looks like it was done with an Ice pick and hammer. I'd question if it actually seals when the gun is fired. That can be repaired by drilling it out (size escapes me right now) putting a big plug in it, then drill and tap the plug for the new liner.
---If you choose to keep the existing vent liner check to see if the flash hole is drilled out to 1/16".
---For stuck balls, I've read where shooters use a CO2 discharge kit. It's not recommended to use an air compressor as you are "compressing" more oxygen into the barrel and should you have a static charge......BOOM!!. If you choose to do that point the barrel in a safe direction.....like into a concrete or block wall. That being said concrete or block walls will ricochet .....be very cautious of this.