When I started with round ball loads, I used the 1 1/8th ounce loads for 2 3/4" AA cases, with SR4756 and SR7625.
Due to the lower pressures with these powders than are developed with trap powders like Red Dot, Green Dot, 700X or the other fast powders, I was able to carefully develop smokeless loads that duplicated the old black Powder 12 bore loads Greener mentioned, the 5 dram (136gr.) and 7 dram (191gr.) loads, running 1,350fps to 1,550fps.

Although duplicating those heavy 12 bore loads of the past, the recoil with the slower burning smokeless shotshell powders was perhaps 1/3rd of the BP loads.

Even better ballistics can be developed in most shotguns, smooth ore rifled by using Blue Dot, Longshot, Steel and Reloader 17 powders. Please refer to Lyman's shotshell loading books as well as Ed Huble's most excellent thread here at Nitroexpress.com entitled "12 GA from Hell".

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