Sherman used some boutique components for many of his loads. It seemed to consist of components that he conveniently had on hand, not stuff that the rest of us may have or even be familiar with. A basic knowledge of powder burning rates would leave us rather free to create light target loads by adjusting 12 gauge loads, and use powders we have on hand. If we were to use a standard twelve gauge target load of 1 1/8 ounces of shot, enough Red Dot to give us about 1200 fps at about 9000 psi, such a combination would work as well in a slightly bigger hole, kind of like shooting the same load in an overbored 12 gauge target gun. Yup, the pressure would be a bit lower, but it should still be high enough for good sound and reliable ignition. Real heavy waterfowl loads should be tested, but lighter loads just aren't going to blow up a good ten gauge if you duplicate 12 gauge components and shot weights. A modern overbored twelve is .750 in the bore. A nominal ten gauge bore is .775, about the same difference between a nominal twelve and an overbored twelve. I actually pump up my ten gauge loads from twelve gauge specs, but just a little. Remember, you didn't hear it here. By the way, don't bother to search for 57 size primers for old ten gauge hulls. Just ream the primer pockets, just a little, and seat the 209 size primers so you can more easily duplicate the twelve gauge loads.
