The 17.1 should be the bore diameter. That's about .673, somewhat overbored for a 16ga. Which means you won't want to try and measure choke with one of the "drop-in" gauges because you'll get a misleading result.

Agree with Argo that anything starting with K is odd in French. Might be a German or Dutch name indicating the type of steel used? Although that would be odd coming after "choke".

Last edited by L. Brown; 08/13/16 12:11 PM.