Ed:
Another way to think about it is the .035 represents 35 points of constriction with each point equal to .001".
Each point of constriction then represents an internal diameter change of minus .001" from the diameter of the normal bore. A standard 12 gauge bore is .729". However, the current trend is to provide overbored 12 gauge barrels which are larger than .729" so as to reduce recoil and improve patterns.
Ed Ward
Another way to think about it is the .035 represents 35 points of constriction with each point equal to .001".
Each point of constriction then represents an internal diameter change of minus .001" from the diameter of the normal bore. A standard 12 gauge bore is .729". However, the current trend is to provide overbored 12 gauge barrels which are larger than .729" so as to reduce recoil and improve patterns.
Ed Ward