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A duck hunter from Illinois named Fred Kimble is credited with the invention of the choke tube back in 1866. However, the idea of a choke tube did not start to slowly catch on until around 1959 when Winchester produced their Model 59 with a Versalite choke system. Eventually manufactures started to produce and tweak choke systems into what we have today.
Choke tubes are small tubes, usually a few inches long that constrict the disbursement of shot as it exits the barrel. The way choke is determined is by subtracting the diameter of the bore of a choke tube from the diameter of the bore of the barrel. Let’s say the diameter of the inside of a 12 gauge barrel is .720, and the diameter of the choke tube is .700. That is a .20 of an inch constriction of the shot as it exits the barrel which makes this choke a “Modified” choke size.
The chart below shows the diameter of the many different size chokes.
| CHOKE SIZE |
10/12/16/20 GAUGE |
20/410 GAUGE |
| Cylinder |
.000 |
.000 |
| Light Skeet |
.003 |
.003 |
| Skeet |
.005 |
.005 |
| Improved Skeet |
.007 |
.007 |
| Improved Cylinder |
.010 |
.009 |
| Light Modified |
.015 |
.012 |
| Modified |
.020 |
.015 |
| Improved Modified |
.025 |
.018 |
| Light Full |
.030 |
.021 |
| Full |
.035 |
.024 |
| Extra Full |
.040 |
.027 |
| Super Full |
.050 |
NA |
This chart shows the percentage of shot that is placed inside of a 30” circle fired from various distances indicated in the three columns.
| CHOKE SIZE |
20 Yards |
30 Yards |
40 Yards |
| Cylinder Bore |
80% |
60% |
40% |
| Improved Cylinder |
100% |
77% |
55% |
| Modified |
100% |
83% |
60% |
| Improved Modified |
100% |
91% |
65% |
| Full |
100% |
100% |
70% |
What does all of this mean? A tighter choke, “Full” for example, will keep the pellets in a tighter pattern as opposed to “Cylinder” which will spread the shot pattern out. A Full choke would be used for making a long distance shot; since the pellets are grouped tightly they will travel farther and keep more pellets in the kill zone. A Cylinder choke will quickly spread the pellets which will provide good coverage of pellets in the kill zone for close shots.
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