Nice chart http://www.glencovesportsshop.com/choke.htm

Choke is expressed as the difference between the bore and the constriction at the muzzle, either in thousandths or as a % (12g full choke .040, modified = .020 = half choke, IC = .010 = quarter choke)
The effect of that constriction can be measured as the percentage of pellets in a circle, usually at 40 yards but patterning at the distances one expects to shoot birds is important.
Because small bore guns (usually) have fewer pellets, the percentage will be the same for a given choke but the number of pellets on target/game will be less.
1 1/8 oz 8s = 461 70%= full= 323 pellets
3/4 oz 8s = 308 70%= 216
Therefore, for a clean kill/likely broken target the choke constriction may need to be greater for smallbores.

Last edited by Drew Hause; 12/14/09 04:20 PM.
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