Shotgun choke - will it improve your shooting? Here's how to judge.
doublegunshop.com Shotgun Chokes for 12 bore or 12 gauge guns.
Understanding Chokes Chokes and Choke Accessories | Briley
Mossberg Blog | The A,B,C's of Shotgun Chokes | O.F. Mossberg & Sons, Inc.
Shotgun Chokes Explained - a Guide to Markings, Sizes & Patterns | The Yorkshire Gent
Understanding Shotgun Chokes - How to Choose a Size for Hunting
Understanding Chokes Chokes and Choke Accessories | Briley
Shotguns
Choke (firearms) - Wikipedia
Shotgun chokes explained, from the 1983 edition of The Gun Digest. Very interesting read, for those who would like to know more about what their shot is going through. : r/Shotguns