June 24th, 2011, 12:23 PM
I use Lapua cases and you have recognize that they have more volume than most cases so they can use more powder. The powder charge weight range should still be safe for smaller volume cases.
I based my estimates on;
- Lapua case
- OAL of 2.83"
- Nosler 168gn CC bullet
I used my QuickLOAD ballistics software to estimate pressures and muzzle velocities.
The estimated results;
44.2 - 45.2 grains of IMR 4007 SSC should be the range of charge weights that would give you the greatest chance of an accurate load. This range should keep your pressures at no more than about 49,000 PSI at the top end (using the Lapua case) and the muzzle velocity being about 2560 FPS with that pressure. If I had to guess, I would say that the most accurate powder charge weight will be around 45 grains plus or minus a couple of tenths of a grain using the Lapua case.
Originally Posted by Charon
168 Nosler Competition. Various cases - Lapua, Remmington BR (friend gave me 100), Winchester.
The M1a NM shoots well with the above and 41.2 g IMR 4064 (which I meant to buy--- duuuuumy me)