Roundball makes some excellent points. There is a lot that modern shotgun shooters can learn from "the old timers".
Two things that "r.b." did not touch on have to do with shot sizes and powder burning characteristics.
Optimum black powder shotshell loads for cylinder bores (no more than "volume for volume", powder to shot)tend to generate no more than 1100 f.p.s. and, quite often, anywhere from 100 to 250 f.p.s. less than that. To compensate for the reduced pellet energy that is generated by such loads it is a good idea to "come up" one to two shot sizes from "standard loads".
For example, if #6 shot is usually preferred for pheasants then #5 shot would most likely be preferred in "cylinder bore loads". The larger shot size would also indicate heavier shot charges in order to achieve something like the pellet count of the "old" smaller shot size.
Powder burning characteristics are of less moment than shot size but they are worth considering, nonetheless. "Low pressure" powders very often reduce shot deformation and, thus can help to "fill out" cylinder bore patterns. One of the best "l.p." powders is good old black powder, Fg or Ffg granulations preferred. Messy as "the old soot" is, there are good reasons why black powder ("drams equivalent") is still the shotgun powder that sets the standard for all the others.
Loads such have just been described are not limited in their applications to just "c.b." bored guns. They can also be deadly long-range loads in tightly-choked guns when lead or "lead density" shot is used. Both Don Zutz and Gough Thomas wrote about such loads. In a 2 2/4-inch 12-gauge case, for example, such loads would involve a 1 1/2-ounce shot charge sent out at 1100 f.p.s. or less. Zutz opined that the minimum shot size for such loads would be American #4s. (Thomas touted British #4s, which are almost identical to American #5s.) Zutz claimed that American #4s from such loads would be more than capable on large ducks and American #3s and #2s would be more than adequate for geese, assuming proper patterns could be generated in the guns being used.
Like "r.b." I would not be too quick to disparage the shooting abilities of cylider bore guns. Today's Sporting Clays shooters have rediscovered what many of the oldtimers always knew. It is amazing how far open-choked guns can "reach out" when they are properly loaded and when the shooter has confidence in their abilities to do so.
