Today I got a quick start on testing some new loads for my Remington Sendero .300RUM. The WC860 (a surplus .50 BMG powder) was purchased from Pat's Reloading for $46/8lb can. Why surplus? If you've ever loaded for this round, you know it uses lots of powder. I started very conservatively because there's no book for this powder; just recommendations from guys like Pat.
Today I didn't have much time to spend shooting; started firing at 0945, quit 1030. Temp 54deg. F., full value breeze 3-8mph; all shot at 200 yds.
Note: If someone has implemented a spreadsheet/database for reloading, please let me know, as this is my first post in a long time here. I'll gladly submit in excel format.
My first group (all groups 3-shot) used the 220gr SMK over 87gr WC860, yielding 2492fps avg., av dev 12.78. The group was = 1.19 moa, vert spread 5/8".
Next grp used 88gr yielding 2490fps av., av dev = 22.33. Group = 1.125 moa, vertical string.
The third group used 89gr yielding 2501fps. avg., av dev = 9.67. Group = 1.25 moa, 1" vertical.
The fourth group used 90 gr yielding 2540 fps avg., av dev = 39.67. Group was 1.13 moa, 2 1/8" vert.
The last group switched to a 208 gr A-Max over 90 grains. Velocity = 2506 avg., av dev = 30.0. Group = .81 moa.
As expected with these velocities, some keyholing was evident due to insufficient spin to stabilize these very high B.C. rounds. That said, I'll have to find some round nose 220's to try. I'm surprised at the group sizes, given the keyholing and variable wind. Next up are some hotter loads, concentrating on the 208gr A-Max bullet (hunting season upcoming). We're moving right now, so test sessions will be few and far between, while the new house gets built. My reloading shop is now relocated to storage.