Chris,

At one time, someone talked about rifling the choke on a shotgun. I don't remember much of the discussion but if there is anyone who could rifle the choke and convert your shotgun into a paradox, that could be interesting.

Another option (and perhaps less expensive) would be to ream out the choke and install choke tubes flush with the muzzle which would allow you to install a rifled choke (or any other choke).

I installed a rifle choke on my Beretta A400 and was surprised how accurate it was.