You should be able to find lots of threads on turkey loads in this forum and in the
Muzzleloading Hunting. Another great place to start is Forum member George's
Blackpowder Notebook website, and in particular the articles
Blackpowder Shotgun Basics and
The Versatile Smoothbore .
To summarize my observations in what has been reported here and elsewhere, the "equal volume load" with the same measure for powder and shot is a good starting place, but for the tight pattern required for turkey, in cylinder bores many have used the trade-off between pattern density and shot velocity and found their optimum with shot loads varying from 1.1/4 to 1.1/2 times the volume of powder used. For example, with 62gr/2.1/4dr of powder, an equal volume load would be 7/8oz of shot; 1/4 more by volume would be about a 75gr/2.3/4dr powder measure for 1.1/8oz of shot, 1/3 more would be about an 82gr/3dr measure for 1.1/4oz of shot, and 1/2 more would be an 89gr/3.1/4dr measure for 1.3/8oz. Note, however, that the comparatively narrow diameter of a powder measure tends to throw a lighter shot charge than the traditional equivalents marked on the fatter combination shot and powder scoops, and this difference increases as the shot size increases. As I said, the increased pattern density has to be balanced against a decrease in penetration and you have to find the optimum for your firelock as you load it. Some use larger shot than they would use in a modern gun - #6 at the smaller end and often #5 or #4 - to carry the energy better if the velocity is very low.
Also, hard/magnum shot helps get as much out of the pattern and the penetration as one can, and if one is willing to be less traditional/authentic in one's loads, some form of shot protection (paper, card, or, for some, plastic) often helps wring everything one can get out of the pattern.
Regards,
Joel
