7MM WSM velocities
After reading a post about WSM loads, I got curious about what velocities Mine is cranking out. I borrowed my pals CHRONY that we have used to develop loads in the past and was quite amazed. I tested 2 bullets, the nosler 160accubond and the speer 145 grand slam. The nosler had 72 grains of MAGPRO behind it and it registered 3289 to 3350 fps
The grand slam had 73 grains of MAGPRO behind it and it clocked 3300 to 3350.
The H4350 was behind a hornady 139 grain BTSP and it wasnt consistent. 3189 to 32?? if I remember correctly. The tests were inconclusive with the h4350, it wasnt real accurate and the wind was blowing the CHRONY off the table at that point.
I am truly amazed with the 160 grain loads. That is an unexpected velocity. I was thinking of more like 3150 or so. It was real accurate at those upper registers along with the grand slam being accurate as well. A slight bit of warning though, the primers and brass did start showing excessive pressure signs with the 160 grain loading of 72 grains of magpro.
I thought the CHRONY was just wigging out so I checked it against a known 243 loading and it came right out. The 243 loading is a 100 grain hornady BTSP in front of 40 grains of H4350 at 2950 fps.
So, the WSM project is coming off nicely! EJ