Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 160gr | Speer Hot-Cor bullet and 97 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, ReloadSwiss RS 70 and Alliant Reloder-17.
Important Notice: DO NOT go below Minimum Charge or above Maximum Charge. Since we have no control over the equipment and components used, any responsibility and liability for the results achieved is rejected.
Only powders/loads that match the current filter criteria are displayed: max pressure of a load ≤ 90% of max. standardized pressure, fill rate ≥ 80% and propellant combustion ≥ 95%. Use the sliders above the tables to adjust these thresholds.
Charge: Powder weight in grains. Start with the minimum load and work up carefully.
FR (Fill Rate): Case fill as a percentage. Values above 100% mean compressed loads.
MaxP / %: Maximum chamber pressure in bar and as a percentage of the standardized maximum for this caliber.
V(0): Muzzle velocity in feet per second (fps) at the standardized barrel length.
z (Powder Burn): Estimated propellant combustion percentage at bullet exit.
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You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 82% | 56,782 psi | 87% | 2680 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 57,696 psi | 89% | 2756 fps | 99.3% |
| Accurate 3100ᴾ | <<locked>> | 100% | 55,825 psi | 86% | 2802 fps | 99.9% |
| Accurate 4064 | <<locked>> | 84% | 57,203 psi | 88% | 2736 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 58,305 psi | 90% | 2851 fps | 100% |
| Accurate MAGPROᴾ | <<locked>> | 100% | 58,291 psi | 90% | 2949 fps | 97.2% |
| ADI AR 2208 | <<locked>> | 86% | 57,029 psi | 88% | 2769 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 55,259 psi | 85% | 2841 fps | 98.6% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 56,521 psi | 87% | 2894 fps | 97.8% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 56,434 psi | 87% | 2890 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 55,347 psi | 85% | 2838 fps | 98.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 57,725 psi | 89% | 2789 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 58,160 psi | 89% | 2815 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 58,755 psi | 90% | 2900 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 56,260 psi | 87% | 2871 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 58,131 psi | 89% | 2884 fps | 99% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 55,593 psi | 86% | 2887 fps | 98.8% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 52,533 psi | 81% | 2818 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 45,614 psi | 70% | 2753 fps | 99.6% |
| Alliant Reloder-26 | <<locked>> | 98% | 56,550 psi | 87% | 2959 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 51,024 psi | 78% | 2815 fps | 98% |
| Bofors RP3 | <<locked>> | 84% | 55,129 psi | 85% | 2756 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 55,593 psi | 86% | 2887 fps | 98.8% |
| Bofors RP7 | <<locked>> | 90% | 57,943 psi | 89% | 2799 fps | 99.4% |
| Hodgdon H380 | <<locked>> | 84% | 55,535 psi | 85% | 2776 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 56,521 psi | 87% | 2848 fps | 99.6% |
| Hodgdon H4350 | <<locked>> | 88% | 56,057 psi | 86% | 2808 fps | 98.9% |
| Hodgdon H4831 | <<locked>> | 98% | 56,507 psi | 87% | 2835 fps | 97.1% |
| Hodgdon H4831 SC | <<locked>> | 98% | 55,608 psi | 86% | 2822 fps | 97% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 55,390 psi | 85% | 2776 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 56,884 psi | 88% | 2808 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 44,773 psi | 69% | 2789 fps | 97.4% |
| Hodgdon Superformance | <<locked>> | 90% | 56,768 psi | 87% | 2887 fps | 99.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,492 psi | 56% | 1716 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 57,348 psi | 88% | 2769 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,463 psi | 87% | 2749 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 55,259 psi | 85% | 2733 fps | 99.5% |
| IMR 4350 | <<locked>> | 92% | 55,419 psi | 85% | 2779 fps | 99.2% |
| IMR 4451 Enduron | <<locked>> | 88% | 56,202 psi | 86% | 2776 fps | 99.5% |
| IMR 4831 | <<locked>> | 94% | 58,349 psi | 90% | 2838 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 56,101 psi | 86% | 2792 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 58,146 psi | 89% | 2825 fps | 97.6% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 53,896 psi | 83% | 2864 fps | 97.4% |
| Lovex S060 | <<locked>> | 82% | 57,783 psi | 89% | 2733 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 56,695 psi | 87% | 2743 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 56,173 psi | 86% | 2769 fps | 99.9% |
| Lovex S070 | <<locked>> | 92% | 57,566 psi | 89% | 2812 fps | 99.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 46,485 psi | 72% | 2661 fps | 99.1% |
| Norma 201 | <<locked>> | 82% | 58,001 psi | 89% | 2753 fps | 100% |
| Norma 202 | <<locked>> | 82% | 58,552 psi | 90% | 2743 fps | 100% |
| Norma 203B | <<locked>> | 84% | 57,450 psi | 88% | 2799 fps | 100% |
| Norma 204 | <<locked>> | 92% | 56,391 psi | 87% | 2835 fps | 98.6% |
| Norma MRP | <<locked>> | 98% | 55,143 psi | 85% | 2913 fps | 99.6% |
| Norma URP | <<locked>> | 92% | 56,420 psi | 87% | 2828 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 58,262 psi | 90% | 2825 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 54,201 psi | 83% | 2881 fps | 97.8% |
| Ramshot Hunter | <<locked>> | 92% | 55,405 psi | 85% | 2835 fps | 99.9% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 48,486 psi | 75% | 2759 fps | 98.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,202 psi | 57% | 1755 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 55,259 psi | 85% | 2759 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 55,956 psi | 86% | 2864 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 57,856 psi | 89% | 2871 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 56,318 psi | 87% | 2900 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 44,701 psi | 69% | 2782 fps | 98.4% |
| Rottweil R 902 | <<locked>> | 84% | 58,523 psi | 90% | 2753 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 55,274 psi | 85% | 2753 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 56,956 psi | 88% | 2812 fps | 97.9% |
| Rottweil R 905 | <<locked>> | 98% | 57,638 psi | 89% | 2874 fps | 99% |
| Rottweil R 907 | <<locked>> | 90% | 57,943 psi | 89% | 2799 fps | 99.4% |
| Shooters World Long Rifle | <<locked>> | 90% | 56,173 psi | 86% | 2769 fps | 99.9% |
| Shooters World Precision | <<locked>> | 84% | 56,695 psi | 87% | 2743 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 57,566 psi | 89% | 2812 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 56,840 psi | 87% | 2812 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 57,754 psi | 89% | 2782 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 58,450 psi | 90% | 2677 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 56,014 psi | 86% | 2638 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 56,057 psi | 86% | 2726 fps | 99.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 57,145 psi | 88% | 2867 fps | 99% |
| Somchem S335 | <<locked>> | 82% | 58,392 psi | 90% | 2677 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 58,581 psi | 90% | 2795 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 58,697 psi | 90% | 2805 fps | 97.4% |
| Somchem S365 | <<locked>> | 94% | 56,188 psi | 86% | 2835 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 58,291 psi | 90% | 2848 fps | 99.5% |
| Vihtavuori N135 | <<locked>> | 82% | 55,492 psi | 85% | 2661 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 55,695 psi | 86% | 2680 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 56,434 psi | 87% | 2723 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 54,984 psi | 85% | 2776 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 53,679 psi | 83% | 2766 fps | 98.8% |
| Vihtavuori N540 | <<locked>> | 84% | 57,435 psi | 88% | 2723 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 57,841 psi | 89% | 2831 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 58,668 psi | 90% | 2890 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 55,405 psi | 85% | 2904 fps | 97.3% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 58,378 psi | 90% | 2792 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 56,521 psi | 87% | 2848 fps | 99.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 47,747 psi | 73% | 2884 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 58,102 psi | 89% | 2792 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 58,349 psi | 90% | 2841 fps | 98.9% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 53,243 psi | 82% | 2635 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 50,749 psi | 78% | 2651 fps | 98.4% |
| Accurate 3100 | <<locked>> | 84% | 32,605 psi | 50% | 2375 fps | 95.4% |
| Accurate 4064 | <<locked>> | 80% | 50,459 psi | 78% | 2641 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,551 psi | 59% | 2523 fps | 98.8% |
| Accurate MAGPRO | <<locked>> | 96% | 50,531 psi | 78% | 2825 fps | 95.6% |
| ADI AR 2208 | <<locked>> | 80% | 47,340 psi | 73% | 2621 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 42,482 psi | 65% | 2615 fps | 95.8% |
| ADI AR 2213 | <<locked>> | 94% | 46,267 psi | 71% | 2713 fps | 95.3% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 52,562 psi | 81% | 2831 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 40,030 psi | 62% | 2562 fps | 95.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,892 psi | 74% | 2641 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 51,082 psi | 79% | 2710 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 37,550 psi | 58% | 2533 fps | 98.9% |
| Alliant Reloder-17 | 51.1 gr | 80% | 42,525 psi | 65% | 2651 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 39,610 psi | 61% | 2556 fps | 95% |
| Alliant Reloder-22 | <<locked>> | 90% | 39,769 psi | 61% | 2602 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,601 psi | 42% | 2297 fps | 97% |
| Alliant Reloder-25 | <<locked>> | 88% | 31,169 psi | 48% | 2411 fps | 95.2% |
| Alliant Reloder-26 | 52.4 gr | 80% | 29,428 psi | 45% | 2402 fps | 95.3% |
| Bofors RP15 | <<locked>> | 94% | 41,800 psi | 64% | 2644 fps | 95.7% |
| Bofors RP3 | <<locked>> | 80% | 48,501 psi | 75% | 2657 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 39,769 psi | 61% | 2602 fps | 95.2% |
| Bofors RP7 | <<locked>> | 80% | 42,409 psi | 65% | 2533 fps | 96.9% |
| Hodgdon H380 | <<locked>> | 80% | 48,733 psi | 75% | 2667 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 80% | 40,466 psi | 62% | 2569 fps | 97% |
| Hodgdon H4350 | <<locked>> | 80% | 43,468 psi | 67% | 2589 fps | 96.5% |
| Hodgdon H4831 | <<locked>> | 94% | 49,574 psi | 76% | 2723 fps | 95.6% |
| Hodgdon H4831 SC | <<locked>> | 94% | 48,530 psi | 75% | 2703 fps | 95.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 35,201 psi | 54% | 2431 fps | 99.3% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 53,113 psi | 82% | 2756 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 39,262 psi | 60% | 2657 fps | 95.3% |
| Hodgdon Superformance | <<locked>> | 80% | 39,305 psi | 60% | 2575 fps | 96.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,282 psi | 42% | 1532 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,882 psi | 83% | 2720 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,806 psi | 77% | 2651 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,982 psi | 80% | 2684 fps | 99.1% |
| IMR 4350 | <<locked>> | 80% | 38,189 psi | 59% | 2467 fps | 95.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,990 psi | 68% | 2566 fps | 97.7% |
| IMR 4831 | <<locked>> | 80% | 37,043 psi | 57% | 2477 fps | 98.6% |
| IMR 4895 | <<locked>> | 80% | 52,417 psi | 81% | 2736 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 48,124 psi | 74% | 2661 fps | 95.5% |
| IMR 7828 SSC | <<locked>> | 96% | 47,036 psi | 72% | 2743 fps | 95.7% |
| Lovex S060 | <<locked>> | 80% | 54,360 psi | 84% | 2684 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 50,082 psi | 77% | 2648 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,481 psi | 64% | 2516 fps | 98.4% |
| Lovex S070 | <<locked>> | 80% | 39,668 psi | 61% | 2500 fps | 97% |
| Lovex S071 | <<locked>> | 88% | 31,691 psi | 49% | 2352 fps | 95% |
| Norma 201 | <<locked>> | 80% | 54,534 psi | 84% | 2703 fps | 100% |
| Norma 202 | <<locked>> | 80% | 55,013 psi | 85% | 2697 fps | 100% |
| Norma 203B | <<locked>> | 80% | 50,444 psi | 78% | 2697 fps | 100% |
| Norma 204 | <<locked>> | 84% | 42,917 psi | 66% | 2602 fps | 95.8% |
| Norma MRP | <<locked>> | 86% | 36,477 psi | 56% | 2556 fps | 95.6% |
| Norma URP | <<locked>> | 80% | 38,319 psi | 59% | 2516 fps | 98.7% |
| Ramshot Big Game | <<locked>> | 80% | 50,923 psi | 78% | 2720 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 44,005 psi | 68% | 2697 fps | 95.2% |
| Ramshot Hunter | <<locked>> | 80% | 37,072 psi | 57% | 2503 fps | 96.9% |
| Ramshot Magnum | <<locked>> | 94% | 38,957 psi | 60% | 2572 fps | 95.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,775 psi | 43% | 1568 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 48,646 psi | 75% | 2654 fps | 99.1% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 45,179 psi | 70% | 2700 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 38,435 psi | 59% | 2543 fps | 98.6% |
| ReloadSwiss RS 70 | 51.9 gr | 80% | 37,086 psi | 57% | 2549 fps | 98% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 36,143 psi | 56% | 2579 fps | 95.2% |
| Rottweil R 902 | <<locked>> | 80% | 51,938 psi | 80% | 2657 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 45,571 psi | 70% | 2605 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 44,208 psi | 68% | 2598 fps | 95% |
| Rottweil R 905 | <<locked>> | 88% | 41,336 psi | 64% | 2592 fps | 95.8% |
| Rottweil R 907 | <<locked>> | 80% | 42,409 psi | 65% | 2533 fps | 96.9% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,481 psi | 64% | 2516 fps | 98.4% |
| Shooters World Precision | <<locked>> | 80% | 50,082 psi | 77% | 2648 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 39,668 psi | 61% | 2500 fps | 97% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 46,659 psi | 72% | 2657 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 54,056 psi | 83% | 2733 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 55,172 psi | 85% | 2635 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,731 psi | 72% | 2510 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,422 psi | 62% | 2461 fps | 97.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 40,959 psi | 63% | 2585 fps | 95.6% |
| Somchem S335 | <<locked>> | 80% | 54,940 psi | 85% | 2635 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 45,876 psi | 71% | 2605 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 48,138 psi | 74% | 2641 fps | 95.2% |
| Somchem S365 | <<locked>> | 80% | 34,867 psi | 54% | 2477 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 36,767 psi | 57% | 2467 fps | 95.2% |
| Vihtavuori N135 | <<locked>> | 80% | 52,301 psi | 80% | 2621 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 52,315 psi | 80% | 2635 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,772 psi | 67% | 2536 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 39,653 psi | 61% | 2513 fps | 98.9% |
| Vihtavuori N165 | <<locked>> | 90% | 38,624 psi | 59% | 2500 fps | 95.4% |
| Vihtavuori N540 | <<locked>> | 80% | 50,604 psi | 78% | 2631 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 39,175 psi | 60% | 2516 fps | 98.7% |
| Vihtavuori N555 | <<locked>> | 80% | 30,530 psi | 47% | 2372 fps | 97.1% |
| Vihtavuori N560 | <<locked>> | 94% | 48,457 psi | 75% | 2785 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,667 psi | 59% | 2484 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 40,712 psi | 63% | 2572 fps | 97.1% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,337 psi | 37% | 2270 fps | 95.7% |
| Winchester StaBALL Match | <<locked>> | 80% | 54,317 psi | 84% | 2743 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 41,350 psi | 64% | 2562 fps | 95.5% |
Recommended = one of the top powders for this cartridge and bullet combination.
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 97 powders for .280 Ackley Improved loaded with the .284 | 160gr | Speer Hot-Cor. Alliant Reloder-26 delivers the highest muzzle velocity at 2,959 fps; across all powders the maximum-charge window runs from 1,716 fps to 2,959 fps. Accurate 3100 gives the best case fill at 100 %, and 97 of the 97 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 160.0 gr projectile in 0.284" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate MAGPRO, ADI AR 2213 reach 100 % fill or more at maximum charge, so these are compressed loads: they need a long drop tube to seat cleanly and react sensitively to the case capacity of your own brass lot. Alliant Reloder-26, ReloadSwiss RS 70, Alliant Reloder-17 rank at the top here: for .280 Ackley Improved with the .284 | 160gr | Speer Hot-Cor they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.