The numbers on a choke tube indicate the constriction of the choke tube to a thousand of an inch. For example, the numbers written on a modified choke tube will be 0.705”.
These numbers are a quick way to identify the choke size without having to measure the inside diameter. Other numbers that may be listed on a choke tube include the gauge of the shotgun, pellet size, and model number.
Related – Looking for a new choke tube? Check out the top picks here.
12 Gauge Choke Tube Numbers
| 12 Gauge Choke Type | Diameter |
|---|---|
| Cylinder | 0.729 |
| Skeet | 0.719 |
| Improved Cylinder | 0.716 |
| Modified | 0.705 |
| Improved Modified | 0.695 |
| Full | 0.685 |
20 Gauge Choke Tube Numbers
| 20 Gauge Choke Type | Diameter |
|---|---|
| Cylinder | 0.625 |
| Skeet | 0.621 |
| Improved Cylinder | 0.603 |
| Modified | 0.595 |
| Improved Modified | 0.590 |
| Full | 0.585 |
16 Gauge Choke Tube Numbers
| 16 Gauge Choke Type | Diameter |
|---|---|
| Cylinder | 0.673 |
| Skeet | 0.665 |
| Improved Cylinder | 0.661 |
| Modified | 0.657 |
| Full | 0.624 |
10 Gauge Choke Tube Numbers
| 10 Gauge Choke Type | Diameter |
|---|---|
| Cylinder | 0.775 |
| Improved Cylinder | 0.768 |
| Modified | 0.758 |
| Full | 0.740 |
| Turkey | 0.730 |
For choke sizes of other gauges and brands, see this chart.
Numbers on Choke Tubes
The most common number on a choke tube is the choke size. Both factory and aftermarket choke tubes show the diameter of the choke etched into the outside of the choke.
In order to read the numbers, the choke tube will need to be removed from the barrel. This can be done with a choke wrench used to unscrew the choke.
Choke Tubes Without Numbers
The numbers on a choke tube can become worn or illegible over time. The only way to determine a choke size at this point is to measure the inside diameter of the choke with calipers.
Another way to determine choke size is to look for markings on the end of the choke. Vertical lines can designate the choke size without even having to remove it from the barrel.
Bottom Line
The numbers on a choke tube mean the size of the choke. These measurements are listed to a thousand of an inch. Choke tube numbers are etched into the side walls of the choke.
Popular choke numbers are Cylinder (0.726), Skeet (0.721), Improved Skeet (0.716), Improved Cylinder (0.711), Light Modified (0.706), Modified (0.701), Improved Modified (0.696), Light Full (0.691), Full (0.686), and Xtra Full (0.681).