www.imrpowder.com Hodgdon distributes Winchester, IMR plus Hodgdon powder. Specifically Sierra 160gr bullets weren't mention as one of the component bullets used in their test. Hodgdon used 160gr Nosler partitions starting load 60grs, max 64grs of IMR7828, 162 Hornady SP starting load 61grs, max 65grs of IMR7828. This caliber is one of my favorites and works well at the upper end at or near max loadings, it also is one that may give problems if loaded to lightly! William