Jim:

Thank you - I saw the info you provided the link to, but I can tell you with certainty that my Narragansett copy will not accept a .648" ball and more than about 55 grains of powder, even when an attempt is made to press the powder forward into the chamber before closing the breech - any more (and, usually, some of that amount) is scraped upward and out by the closure of the breech.

mhb - MIke