Originally Posted by .45 Combat
What about just using a full choke, or a modified choke?
You would need to thread the end of a 18.5" to add the choke and the VCS can also add vent ports. I suppose you could find someone to do them both.
What you are indicating is essentially what the back boring acomplishes... they open up the existing bore diameter from the chamber end and the shot gets choked down as it gets to the non-bored area at the end of the barrel.
They think the back boring reduces some of the recoil because of the larger barrel diameter reducing some friction. It would be interesting to chronograph 00 B out of a VCS and non-VCS barrel. Reduced recoil rounds might be a less expensive option.