Thread: Optimal Charge Weight / OCW

Tried OCW test this morning for 150gr Speer SPBT in the 788, progression was sighters (-7%, +2, +2) loads (+2, +0.7, +0.7, +0.7)

Can someone pls try to explain why the focus for OCW is more on POI than group size ? Not sure I get it...

For 2208 the start load is 44.0 and max is 47.0

Measured the groups by zeroing vernier on 308 head, and then measured side to side.

46.3gr: group 1.332, poi 1.356 (low left)
46.6gr: group 0.752, poi 1.716 (low left)
46.9gr: group 0.758, poi 0.807 (low left)
47.2gr: group 0.273, poi 0.808 (low left)

Getting flattish primers, but no cratering or ejector marks on all these loads (210 Fed primers). Bolt lift is heavy on all of them, but that is apparently a known issue on 788 (short handle and steep cocking cam)

Next I'll try some lighter progression - sighters (-10%, +2, +2) loads (+2, +1, +1, +1) so that will give me 44.9, 45.3, 45.8 and 46.3