Anyone have a Chart for Choke sizes

[7.62mm]

Just got a 20 gauge with fixed choke, just trying to figure out what the choke in this shotgun is, I get .595 with the micrometer, any help would be appreciated. I have done some google searches, but haven't found what I am looking for.

Thanks

 

[catnthehatt]

http://www.brownells.com/aspx/NS/GunTech/NewsletterArchive.aspx?p=0&t=1&i=720
try this
Cat