Identifying the degree of choke
Choke tubes are often marked by small notches in the end of the tube , which allow the user to see what choke(s) is in the gun by looking at the muzzle. Browning and a number of other manufacturers use this system
Alway make sure that a shotgun is unloaded and the action is open whenever trying to identify a choke tube by its markings or when changing a choke tube.
Choke Tube Notch System
- Full - 1 notch
- Improved Modified - 2 notches
-
Modified - 3 notches
Improved Cylinder - 4 notches - Skeet - 5 notches
- Cylinder - 0 notches
Never fire a shotgun threaded for choke tubes without the choke tube(s) installed. Besides damaging the threads at the muzzle, the shot and wad column can catch on the threads creating dangerous pressures.
Shotgun Choke Tube Systems
The following Shotguns, which use screw in choke tubes, can use Winchester Win-Choke, Mossberg accu-choke or Browning Invector choke tubes interchangeably.
- Winchester Shotguns except Super X2 & Supreme
- Mossberg Model 500 and Model 9200
- Mossberg Maverick 88
- Browning pumps, semi autos and others shotguns labeled for use with the Browning invector choke tubes but not Invector Plus chokes.
- Miroku
- Stoeger Condor and Uplander model double barrel shotguns
- Thompson Center
- Smith & Wesson
- Weatherby - likely but less certain
- Charles Daly Over& Under current production
- Older Ruger shotguns
Cutts Compensator
Among the first changeable choke systems available for shotguns was the Cutts compensator, which was threaded to use Lyman choke tubes. These were put on a number of pump and semiauto shotguns starting in the 1940's and are still available today.
| Chart for Lyman Choke Tubes | |
|---|---|
| Degree of Choke | Lyman No. |
| Spreader or Skeet | .820 |
| Improved cylinder | .755 |
| Modified | .725 |
| Full | .705 |
| Super Full or Long Range #1 | .690 |
| Mag. Full or Long Range #2 | .680 |
Poly Choke
The poly choke was generally an after market add-on, although a number of Mossberg shotguns were equipped with them at the factory.
They use an adjustable collet, which can be adjusted for different choke settings which may or may not correspond to the markings on the device.
Shotguns with Poly chokes should be stored with the choke the fully open position to ensure that the steel petals don't gain a set .
The Poly Choke II is designed to screw into the existing choke threads of a shotgun barrel.
Identifying the degree of choke in a barrel
Most Shotguns sold today use changeable choke tubes however some older guns and some of the cheaper imported shotguns may have fixed choke barrels. Some barrels will have the degree of choke marked with letters such as IC (Improved Cylinder),M (Modified), F (Full) others may use the following marking system in which one or more asterisks are stamped on the barrel.
Markings For Barrels with Fixed Choke
- One asterisk "*" is Full choke
- Two asterisks is "**" Modified
- Three asterisks is "***" Improved Cylinder
- Four asterisks is generally Skeet "****"