general all-round hunting shotgun, without having excess weight. Shotguns having fixed chokes intended for geese, in contrast, are often found with full choke barrels, in longer lengths, and are much heavier, being intended for fixed use within a blind against distant targets. Defensive shotguns with fixed chokes generally have a cylinder bore choke. Likewise, shotguns intended primarily for use with slugs invariably also are found with a choke that is a cylinder bore. Dram equivalence "Dram" equivalence is sometimes still used as a measure of the powder charge power in a shotgun shell. Today, it is an anachronistic equivalence that represents the equivalent power of a shotgun shell containing this equivalent amount of black-powder measured in drams avoirdupois. A dram in the avoirdupois system is the mass of pound or ounce or 27.3 grains. The reasoning behind this archaic equivalence is that when smokeless powder first came out, some method of establishing an equivalence with common shotgun shell loads was needed in order to sell a box of shotgun shells. For example, a shotgun shell containing a 3 or 3 1/2 dram load of black-powder was a common hunting field load, and a heavy full power load would have contained about a 4 to 4-1/2 dram load, whereas a shotgun shell containing only a 2 dram load of black-powder was a common target practice load. A hunter looking for a field or full power load familiar with black-powder shotgun loads would have known exactly what the equivalence of the shotgun shells would have been in the newly introduced smokeless powder. Today, however, this represents a poorly understood equivalence of the powder charge power in a shotgun shell. To further complicate matters, "dram" equivalence was only defined for 12 gauge shotgun shells, and only for lead shot, although it has often been used for describing other gauges of shells, and even steel shot loaded shells. Furthermore, "dram" equivalence only came around about 15 years after smokeless powder had been introduced, long after the need for an equivalence had started to fade, and actual black-powder loaded shotshells had largely vanished. In practice, "dram" equivalence today most commonly equates just to a velocity rating equivalence in fps (feet-per-second), while assuming lead shot. A secondary impact of this equivalence was that common shotgun shells needed to stay the same size, physically, e.g., 2-1/2 or 2-3/4-inch shells, in order to be used in pre-existing shotguns