* A typical factory 12-gauge barrel measures about .724 inch.
* Many popular turkey guns come with chokes with a .665 constriction, which shoots No. 5 or 6 lead shot extremely tight.
* Super-tight turkey chokes — such as those with .660 constrictions — shoot small shot, such as No. 6, best.
* Chokes with larger constrictions, such as .680, usually work best with larger shot — No. 4 or 5 — or in shotguns with back-bored barrels.
* Hevi-shot produces the tightest patterns through chokes with constrictions of about .675. In testing, Hevi-shot fired through a special .675-constriction tube produced an average pattern density of 94 percent. Hevi-shot fired through a factory full choke (.691 constriction) produced an average pattern density of 88 percent in a 30-inch circle at 40 yards.
* Hevi-shot fired through standard improved-cylinder chokes (.718 constriction) produced an average pattern density of 70 pecent, which is the industry standard for a “full” choke. When Hevi-shot is fired through chokes tighter than .665, pattern density begins to deteriorate.