I would not shoot the dented barrel until it has been fixed. Have a competent workman who uses steel plugs lift the dent for you - the hydraulic ones do not do as good a job. Sometimes simpler really is better.

The mold you have is quite undersize for the bore - usually best results are seen with a bullet half to one thou under the smooth portion. I have not seen a Paradox with this much removed from the bores. If you go to a larger bullet, there's no telling what will happen when it gets to the choke.

Make sure you use the correct alloy of 1 in 15. The ductility of the bullet needs to be correct to go through the choke and perform on game.

Is the gun proofed with 2 3/4" chambers? If not, and it has been reamed to 2 3/4", it's out of proof.