300 Whisper reloading issues and questions

[snipecatcher]

If its a TP555 barrel with his selectable gas block, 2400 will give you plenty of gas for reliable cycling. You should be around 8-9 grains. VVN110 works well too. The 240s take up a lot of case capacity, which is what makes them ideal for subsonic shooting, but above 9 or 10 grains of powder, you run out of capacity, depending on seating depth of course.