jOe,
Briley Manufacturing is just that, a manufacturing company. I previously requested from them thin wall chokes with 2" extending from the muzzle. Briley informed me they could not meet my special request. I understood because as a "manufacturing company" they make a profit producing many, many of the same items. While they can bore any size choke in reference to a specific barrel constriction, they were not "set up" or perhaps they simply did not have the "stock" to easily and efficiently produce my special request. I tend to think your special request fell into the same "not our normal business" range. There is an old adage that applys; "You never make any money on your first try." Yup, been there and done that too many times.
A good machinist/metal fabricator may be able to fulfill your request if he were to either copy (not necessarily ethical) or modify a set of Briley tubes. I think it would however be expensive to do so.
Good luck!
