Choke Tube Identification

Browning choke tubes use several systems for identification. Some are useful in the field, and others when the choke tube is out. Choke tubes supplied with your Browning shotgun often have notches in the top edge which can help you determine the choke constriction. Generally you will need to remove it an read the inscription on the side of the tube. Below are a few helps:

GENERAL ABBREVIATIONS

(as found on product listings)

DESCRIPTIONS

XF

Extra Full

XF TRAP or X-FULL TRAP  

Extra Full Trap Shooting Choke

X FULL TKY-TRAP

Dual use extra full tube for turkey or trap shooting

X FULL TKY

Extra Full Turkey Hunting Choke

F

Full

LF or LFULL

Light Full

IMOD or IM or IMP MOD or I MOD

Improved Modified

MOD or M

Modified

LMOD or LM  or LT MOD or L MOD

Light Modified

IMP CYL or IC  

Improved Cylinder

SK or EXT SKT

Skeet

CYL or C

Cylinder (sometimes incorrectly abbreviated to CLY)

SPREADER

Special tube with a form of "rifling" that spreads the pattern rapidly, for close in upland hunting

RIF DEER

Rifled Deer Tube (for shooting slugs, primarily sabots)

 

 

NOTCHES IN RIM OF TUBE 

(OEM Invector and Invector Plus, not found on extended tubes)

I

Full lead or steel, but may be too tight for good steel performance

II

Modified lead, Improved Modifed Steel

III

Improved Cylinder lead, Improved Cylinder Steel

IIII

Skeet lead, Modifed Steel

NONE, no notch

Cylinder lead, Improved Cylinder Steel

 

 

SPECIALTY DESIGNATIONS

 

LONG

Tight constriction tube used for longer ranges, mostly referring to steel shot

MED

Medium constriction for medium ranges with steel shot

CLOSE or CLOSE RANGE

Very open choke tube used for close range shooting with steel shot. 

 

 

OTHER ABBREVIATIONS

 

WF

Waterfowl

TKY

Turkey

INV PLUS

Invector Plus choke tubes

INV

Invector Tubes (Standard Invector)

EXT

Extended choke tube that extends beyond the muzzle

INV DS

Invector-DS Choke Tube System

TNT

Timber and Teal (helically spun to spin shot)

General Pattern Percentages for each Choke Designation

Number of pellets in a 30" circle at 30 yards. Varies with shot size and/or lead vs. steel shot. Steel patterns generally exhibit a higher percentabe in the circle.  IMPORTANT: The following values are approximate. They do vary between gauges and the type, lenght and design of the choke tube. 

12 GAUGE

75%-85% -- Extra Full Trap

55%-85% -- Full 

30%-60% -- Light Modified

45%-75% -- Improved Modified

35%-65% -- Modified

30%-60% -- Light Modified

25%-55% -- Improved Cylinder

20%-45% -- Skeet 

15%-45% -- Cylinder

Very open -- Spreader

 

20 GAUGE 

55%-85% -- Full     

45%-75% -- Improved Modified   I

35%-65% -- Modified

30%-60% -- Light Modified  

25%-55% -- Improved Cylinder

20%-45% -- Skeet 

The Listing is the Exact Listing of Abbreviations and Choke Constrictions for Browning Invector-DS Tubes.

INVECTOR-DS CHOKE, 12, FULL 75-80%
INVECTOR-DS CHOKE, 12, LIGHT FULL 70-75%
INVECTOR-DS CHOKE, 12, IMOD 65-75%
INVECTOR-DS CHOKE, 12, MOD 55-65%
INVECTOR-DS CHOKE, 12, LMOD 45-55%
INVECTOR-DS CHOKE, 12, IC 40-45%
INVECTOR-DS CHOKE, 12, SK 35-40%

INVECTOR-DS CHOKE, 12, FULL, EXTENDED 75-80%
INVECTOR-DS CHOKE, 12, LIGHT FULL, EXTENDED 70-75%
INVECTOR-DS CHOKE, 12, IMOD, EXTENDED 65-75%
INVECTOR-DS CHOKE, 12, MOD, EXTENDED 55-65%
INVECTOR-DS CHOKE, 12, LMOD, EXTENDED 45-55%
INVECTOR-DS CHOKE, 12, IC, EXTENDED 40-45%
INVECTOR-DS CHOKE, 12, SK, EXTENDED 35-40%