Regardless of what gauge, action, chamber or shot size you select, the most critical part of optimizing your turkey gun is patterning. You really should pattern your gun before you hunt. If you use optics or sights they could be off. Even a factory-installed bead might not be dead-on. Furthermore, every gun/load/choke combo shoots a little differently. In some cases, standard 2-3/4-inch loads may actually pattern better than 3-inch loads in your gun. Or, harder, copper-plated shot may pattern better in a full or modified choke than in a super-full turkey choke. You may find your gun patterns better with Winchester, Remington, or Federal ammunition. The only way to find out is to practice, before you hunt.
Bob Humphrey is a certified wildlife biologist, registered Maine guide, award winning outdoor writer and turkey hunter of some renown. In addition to thousands of magazine articles, he’s authored two books on turkey hunting, available at: http://www.bobhumphrey.com/books.html