I tested 4 powders for my Glock 23. Unique, AA#5, Power Pistol, and Winchester Super Field WSF using 165 jacketed HP's and FMJ's plus 155 Hornady XTP-HP's and RP 165 gr. Golden Sabers. My choice would be WSF 1st followed closely by Power Pistol and Unique and while AA#5 worked well it would be my last pick of the 4. All these powders performed well but WSF had noticeably less felt recoil and showed velocity that matched my reload data. All 4 more than half filled the case and would not allow a double charge. There are several good powders for 40SW but I've only tested these 4 and now load everything with WSF.