There is a great deal of confusion between marjoram and oregano. They are related plants, but are two different species. They also taste similar, although oregano often has a stronger flavor, and both contain high amounts of antioxidants. To make it even more confusing, cretan oregano, O. onites, is also called French or pot marjoram and Greek oregano, O. vulgare, is often called wild marjoram.
Cylinder choke is an unconstricted barrel. The shot pattern spreads quickly. Improved Cylinder choke has a slight constriction. It allows the shot pattern to spread fairly quickly. This is a good choice for quail, rabbits, and other upland game. Modified choke has moderate constriction. The shot stays together longer, making the pattern denser and more useful at longer ranges. This choke is used often for dove hunting and is the preferred choke when using steel shot to hunt for ducks or geese.
Choke is performance-based, often having very little to do with what a barrel or a screw-choke tube is marked. Choke is also not design-based or constriction-based. Though shotgunners have picked up on the word constriction, there is no such thing as a choke marked as to actual constriction.