Patterns are shot with 2 3/4" ammunition in 3" chambers. The following average pattern percentages are expected in Browning barrels when shot with lead ammunition at 40 yards:

 

DESCRIPTION	PATTERN PERCENTAGE
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%
INVECTOR, STD/PLUS CHOKE, 12, X-FULL	75-85%
INVECTOR, STD/PLUS CHOKE, 12, FULL	55-85%
INVECTOR, STD/PLUS CHOKE, 12, LIGHT FULL	50-70%
INVECTOR, STD/PLUS CHOKE, 12, IMOD	45-75%
INVECTOR, STD/PLUS CHOKE, 12, MOD	35-65%
INVECTOR, STD/PLUS CHOKE, 12, LMOD	30-60%
INVECTOR, STD/PLUS CHOKE, 12, IC	25-55%
INVECTOR, STD/PLUS CHOKE, 12, SK	20-45%
INVECTOR, STD/PLUS CHOKE, 12, CYL	15-45%

1. Specifications outlined above would also apply to 2 1/2" .410 ammunition in 3" chambers.
2. Where facilities do not exist for patterning 28 gauge open chokes at 40 yards, 25 yard patterning may be substituted with percentages     adjusted proportionately.
3. Double Barrel Guns -- Where one barrel has a different choke than the other, the more open choke should not shoot a tighter pattern than  the tighter choke.
4. Steel Shot -- normally steel shot shoots one choke size tighter than lead in the same choke tube. 

 To see what choke tubes are available for your shotgun, you can either look in our online catalog or refer to your owner's manual.