What are folks thoughts on a good starting load for 320 grain Woodleigh PPSN and FMJ bullets in a 9.3x74R using IMR4064? I contacted Woodleigh and they do not have any IMR4064 load data. In Pierre van der Walt's book the largest projectile listed with load data for IMR4064 is 286 grain bullets. The max load listed is 56.5 grains (from the Nosler Reloading Guide No. 6). For 270 grain bullets the max load for IMR4064 is 58 grains (from the Speer Reloading Manual No. 14). Just trying to extrapolate a bit I was thinking about starting with 52 grains with 320 grain bullets. Does that sound about right? Anyone played with similar loads or have any Quickload data? Thanks.

Mike,
I haven’t tried to load the 320gr but I think you are on the right track. You might try the starting load for the 286gr bullets or reduce it say 5gr more. There is only 34gr difference.
Bill

Well I am sort of wandering into a solution. I have some 300 grain Swift A Frames. So I reduced my load that I used for 286 grain bullets by one grain (it was not a max load to begin with) to 54 grains and loaded the 300 grain bullets. I will see how 54 grains of IMR4064 works with the 300 grain bullets and then adjust for the 320 grain bullets. If there are no pressure signs or velocity excursions with the 54 grain/300 grain load, I should be okay to try a 52 grain/320 grain load. Stay tuned.

The VV manual lists 3 loads for the 320gr bullet.
N135 45 to 49gr
N140 47 to 52gr
N540 49 to 54gr
You could probably look at the burn rate chart in one of the other manuals and see where these powders compare to 4064.

Thanks. The chart I have shows N140 as the slowest of the three and N135 as the fastest of the three. N540 is in the middle. N135 is shown as being slightly slower than IMR4064. Maybe 50 grains would be a better starting point.

VV's numbering system makes no sense. I have tried N550 in my 9.3 Chapuis but it didn't work very well and it is hard to find the VV powders. I subscribe to Loaddatta.com. For $25 a year it is a handy way to find just about every load that has ever been published including all the old "Handloader" articles.