Today I ran the OCW shown below for my first use of Lapua cases and a switch to CCI41 primers.
Constants:
- Rifle: Sako 85 Varmint, .223, 24", 1-8"
- Sighted 0.25" high/left of bull for 24.5gr "Pet" load
- 100 yards
- Bullet: 75gr Hornady HPBT
- Powder: N-140
Previous "Pet" loads:
- Case: Federal, previously fired
- Primer: Federal
- Trim Length: 1.752"
- COL: 2.250"
- No crimp
- 22.0 gr, 2435 fps, [email protected]", [email protected]"
- 24.5 gr, 2776 fps, [email protected]"
- (21.5, 22.5, 23.0 were 0.72" - 0.97")
- (23.5, 24.0, 25.0 were 1.21" - 1.77")
OCW:
- Case: Lapua, unfired, chamfered only.
- Trim: 1.750 (from factory, measured)
- COL: 2.250
- No crimp
- 3 sighters (not shown)
- 9x3-shot grps in 0.4 gr increments from 21.2 gr to 24.4 gr
- All grps targeted at there respective bullseye.
Had originally wanted to run 24.8 and 25.2, supported by VV's online data showing 25gr max. But Hornady's book showed 23.6 gr max from a 20" Colt AR15, 2600 fps. And 24.4 gr in the Lapua case looked to make any more powder a compressed load not noted in the VV data.
Conclusions:
1) There appears to be a relatively large forgiving zone from 21.8 to 23.4, velocities ~2500-2670 fps. The same conclusion is also hinted at in my non-OCW tests using Federal materials.
2) There could be another sweet spot above 24.4. Although the primers looked OK and there were no other signs at 24.4, the velocities are reaching above published data (that I have).
3) Velocity from the Lapua/CCI combo was slightly higher than the Federal/Federal combo. My guess is it comes from the Lapua's slightly lower volume (?).
4) Accuracy with the Lapua/CCI combo was better, but maybe I'm (finally) improving a bit lol.
Questions:
1) Is it posisble to have such a broad zone of forgiving lol?
2) Assuming 100-300yd shooting, what load would you choose/explore and why?
3) Did I miss anything?
Constants:
- Rifle: Sako 85 Varmint, .223, 24", 1-8"
- Sighted 0.25" high/left of bull for 24.5gr "Pet" load
- 100 yards
- Bullet: 75gr Hornady HPBT
- Powder: N-140
Previous "Pet" loads:
- Case: Federal, previously fired
- Primer: Federal
- Trim Length: 1.752"
- COL: 2.250"
- No crimp
- 22.0 gr, 2435 fps, [email protected]", [email protected]"
- 24.5 gr, 2776 fps, [email protected]"
- (21.5, 22.5, 23.0 were 0.72" - 0.97")
- (23.5, 24.0, 25.0 were 1.21" - 1.77")
OCW:
- Case: Lapua, unfired, chamfered only.
- Trim: 1.750 (from factory, measured)
- COL: 2.250
- No crimp
- 3 sighters (not shown)
- 9x3-shot grps in 0.4 gr increments from 21.2 gr to 24.4 gr
- All grps targeted at there respective bullseye.
Had originally wanted to run 24.8 and 25.2, supported by VV's online data showing 25gr max. But Hornady's book showed 23.6 gr max from a 20" Colt AR15, 2600 fps. And 24.4 gr in the Lapua case looked to make any more powder a compressed load not noted in the VV data.
Conclusions:
1) There appears to be a relatively large forgiving zone from 21.8 to 23.4, velocities ~2500-2670 fps. The same conclusion is also hinted at in my non-OCW tests using Federal materials.
2) There could be another sweet spot above 24.4. Although the primers looked OK and there were no other signs at 24.4, the velocities are reaching above published data (that I have).
3) Velocity from the Lapua/CCI combo was slightly higher than the Federal/Federal combo. My guess is it comes from the Lapua's slightly lower volume (?).
4) Accuracy with the Lapua/CCI combo was better, but maybe I'm (finally) improving a bit lol.
Questions:
1) Is it posisble to have such a broad zone of forgiving lol?
2) Assuming 100-300yd shooting, what load would you choose/explore and why?
3) Did I miss anything?
