My buddy,ever helpful,gave me a box of Hornady 150 BTSP,since I had some 4064 for my 303,I tried them. After getting to 51.5gr and one big messy hole,I had to buy 4# of IMR-4064 and a couple of boxs of 150 BTSPs.When I mentioned the group,he said the old match load was 52.0gr.