Here's one of Dogs and Doubles site:

http://www.dogsanddoubles.com/2013/04/good-gun-alert-an-awesome-16-gauge-j-p-sauer-hammergun/


CAL: 170 D BERN
CAL; 168 D BERN

Not sure if the D BERN is a higher grade pattern welded tube that the S BERN.

DD: do you have a more in-focus image?

Kind Regards,

Raimey
rse