And the other thing, the book is wrong many, many times
Jack Puglisi use say to me, the book was great most of the time and a "curse" other times , you could have a gun right as rain (as he use to say) but the book says a gun has 30" barrels but the gun you are looking at has 28" and they have not been cut with the end of rib matting, but now the gun is cursed because the book says so
There are many misprints in "The Book". Just food for thought.