Shotgun Choke Patterns and Information
The amount of choke in a barrel is determined by
subtracting the inside diameter of the choked area from the diameter of
the bore, both measured with special gauges. Choke is considered
Full if its choke diameter is .035 inches smaller than the bore.
Caution: Just because your gun delivers Modified (or
whatever) performance with one load doesn't necessarily mean it will do
the same with other loads. Also keep in mind that just because the barrel
of a gun or its screw-in choke was marked "Modified" or
"Improved Cylinder" at the factory does not mean it will deliver
Modified or Improved Cylinder choke performance with all loads.
Different loads from various manufacturers or even different loads from
the same manufacturer can vary. Even though the load you just tested
delivered Modified performance, another load might deliver Improved
Cylinder performance while the next might perform as if your gun is choked
either tighter or looser. Bottom line is shoot your gun at the paper
with different loads and make your own determination of what choke and
load is best suited for your shooting circumstances.