Update: received the Briley 16 gauge choke tube wrench and it fits the Rizzini chokes perfectly.

Thanks again for the help :-)

p.s.
Postoak.....we own or have owned a few models of guns in common I'm sure. Model 12's? Superposed? Darne? Manufrance? Lugers? Hi-powers? The list goes on I'm sure of it.

Dustin.