with the 17.5 grain red dot in 7/8 12 ga load its well under max pressure in the shotgun reloading book at 7500psi (max shotgun pressure at 11500 sammi spec 2 3/4) Im using a mossburg 500 3" chamber, so only a year old it can take full sammi spec. It just seemed pretty concervative in the book with the low pressure
Ok guys i figured it out, a light turned on and looked right on the Alliant website and there online data says 20.5 grn for 9800psi on the rem hull, rem primer , or win AA hull with a winchester primer was 20 grn at 10200psi, as i have heard the cheddite primer is closely related to winchester primers, my 18.5 grn load is still well under there specs. Both at 1345fps