How to fix a ringed chamber in a 32-40?

[guntech]

Do you know who could make a custom reamer for a moderate price?

Have Dave Manson make a custom reamer that will cut the chamber large enough to get rid of that ring without changing the head space... then it will not show up when you fire a case and it will extract just fine. Resizing will work the brass a little but you can always anneal the top of the case to compensate for those few thou.