Last yr my grandson got a 28 ga semi auto and his dad did also. This year I purchased a 28 ga O/U. The receipe I am using is 13 gm Alliant 20/28 (new to me), Win AA HS hulls, Win 209 primers, and Win AA HS wads. They have different brands of semi auto 28 ga shotguns. My problem is that this load will not totally cycle their guns. It begins to open the discharge but does not have enough power to totally eject the shells. Any suggestions with 20/28? How about with other powders? The PSI is listed as 11,670. Many thanks.