Hercules/Alliant Reloaders Guide used to (don't have a current one) have a chart that showed how long an ounce of shot would stack up in the various bores from .410 to 10 ga. Calculating the volume gave an average of around .288 CuIn. For a 1.00" bushing length this would give a dia of about .605" for a 1oz charge. Only thing is they specified neither shot size or alloy. Have often wondered if the different sizes of shot had bore sizes they fit more efficiently than others, but never tried to check it out. Might not mean much with sizes down around #8/#9 but as size increased it would seem likely to me.
Ps; Just read Jim's post. To carry that all the way out to an ounce 55 x 8 would give 440 grains or a "Whopping" error of 2.5 grains. That would equal abut 1 #5 or 2 #7½ size shot. If one needs more precision than that, they don't need to be messing around with a "Shotgun" anyway. Very handy & easy to remember Rule of Thumb Jim.
Last edited by 2-piper; 03/01/09 12:44 AM.
