Ive never owned a 12 gauge with 14 gauge bore in the tubes, but, have owned several that were 11 gauge. I suppose the quest was to improve the performance of ammunition that was still loaded with felt wads and an actual explosive (black powder) propellant. I believe the 12 20 concept took that to an extreme, but, have never owned one of those guns, either.
Maybe someone, here, has and can report how it works?
I think a lot of the magic bore and choke enhancements that were promoted and sold over the years were no more than marketing hype.
Best,
Ted
