Ok, I'm educating myself: Two items I copied a couple of year ago re chokes:
A 12 gauge barrel with no choke restriction at all has an interior dimension of .729 inches in diameter. The following table shows the amount of restriction that is given by applying any of the commonly used chokes:
Cylinder .000 in.
Skeet .005 in.
Improved Cylinder .010
Modified .020
Full choke .035
Thus to determine which choke you have on the shotgun, simply measure the actual interior diameter, then subtract that figure from .729.
If the actual diameter is .729 in., it is a Cylinder choke.
If the actual diameter is .724 in., it is a Skeet choke.
If the actual diameter is .719 in., it is an Improved Cylinder choke.
If the actual diameter is .709 in., it is a Modified choke.
If the actual diameter is .694 in., it is a Full choke.
======== and (European/Brit)
one refers to the choke in a barrel as being true cylinder, improved, quarter, half, three-quarter or full. Gunmakers talk about “points” of choke. They measure shotgun choke relative to the bore diameter (which may vary considerably within any designated bore size rather than at the muzzle alone).
One point equates to a constriction of one thousandth of an inch. Below is what one would expect in a 12-bore gun.
• True Cylinder 0-1 points
• Improved cylinder 3-6
• Quarter (American Improved) 8-12
• Half (American Modified) 17-23
• Three-quarters (Improved Modified) 25-30
• Full 35-40
• Super full 40+
I'll figure it out....so if the bore starts out at 720 rather than a standard 729, I just subtract .009? and maybe I do need one of those bore thingys.. I swore this would not be an obsession... all I need are three shootable SxS's... That's all I need!!!
Last edited by Argo44; 06/23/16 10:00 PM.
