Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 160gr | Speer Magnum Tip Soft Point bullet and 96 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, Norma MRP and Vihtavuori N560.
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% | 57,334 psi | 88% | 2690 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 58,320 psi | 90% | 2772 fps | 99.4% |
| Accurate 3100ᴾ | <<locked>> | 100% | 56,695 psi | 87% | 2818 fps | 99.9% |
| Accurate 4064 | <<locked>> | 84% | 57,769 psi | 89% | 2746 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 55,274 psi | 85% | 2812 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 55,100 psi | 85% | 2904 fps | 96.7% |
| ADI AR 2208 | <<locked>> | 86% | 57,450 psi | 88% | 2779 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 55,840 psi | 86% | 2854 fps | 98.7% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 57,276 psi | 88% | 2910 fps | 98% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 57,217 psi | 88% | 2904 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 58,494 psi | 90% | 2802 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 55,129 psi | 85% | 2776 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 55,840 psi | 86% | 2864 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 57,305 psi | 88% | 2887 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 55,419 psi | 85% | 2848 fps | 98.7% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 56,420 psi | 87% | 2904 fps | 99% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 53,432 psi | 82% | 2831 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 46,354 psi | 71% | 2769 fps | 99.7% |
| Alliant Reloder-26 | <<locked>> | 98% | 57,522 psi | 88% | 2976 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 51,866 psi | 80% | 2831 fps | 98.2% |
| Bofors RP3 | <<locked>> | 84% | 55,883 psi | 86% | 2772 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 56,420 psi | 87% | 2904 fps | 99% |
| Bofors RP7 | <<locked>> | 90% | 58,595 psi | 90% | 2812 fps | 99.5% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 45,832 psi | 71% | 2707 fps | 96.2% |
| Hodgdon H380 | <<locked>> | 84% | 56,246 psi | 87% | 2789 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 57,174 psi | 88% | 2864 fps | 99.7% |
| Hodgdon H4350 | <<locked>> | 88% | 56,739 psi | 87% | 2822 fps | 99% |
| Hodgdon H4831 | <<locked>> | 98% | 57,653 psi | 89% | 2858 fps | 97.4% |
| Hodgdon H4831 SC | <<locked>> | 98% | 56,420 psi | 87% | 2838 fps | 97.2% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 56,130 psi | 86% | 2789 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 57,638 psi | 89% | 2822 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 45,440 psi | 70% | 2805 fps | 97.7% |
| Hodgdon Superformance | <<locked>> | 90% | 57,638 psi | 89% | 2904 fps | 99.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,608 psi | 56% | 1722 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 58,088 psi | 89% | 2785 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,942 psi | 88% | 2762 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 55,927 psi | 86% | 2749 fps | 99.6% |
| IMR 4350 | <<locked>> | 92% | 56,275 psi | 87% | 2795 fps | 99.4% |
| IMR 4451 Enduron | <<locked>> | 88% | 56,811 psi | 87% | 2789 fps | 99.6% |
| IMR 4831 | <<locked>> | 92% | 55,448 psi | 85% | 2802 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 56,608 psi | 87% | 2799 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 55,201 psi | 85% | 2782 fps | 97.1% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 54,737 psi | 84% | 2884 fps | 97.7% |
| Lovex S060 | <<locked>> | 82% | 58,218 psi | 90% | 2743 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 57,188 psi | 88% | 2756 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 57,087 psi | 88% | 2785 fps | 100% |
| Lovex S070 | <<locked>> | 92% | 58,479 psi | 90% | 2828 fps | 99.8% |
| Lovex S071ᴾ | <<locked>> | 100% | 47,340 psi | 73% | 2677 fps | 99.2% |
| Norma 201 | <<locked>> | 82% | 58,508 psi | 90% | 2762 fps | 100% |
| Norma 203B | <<locked>> | 84% | 58,189 psi | 90% | 2815 fps | 100% |
| Norma 204 | <<locked>> | 92% | 56,985 psi | 88% | 2848 fps | 98.7% |
| Norma MRP | <<locked>> | 98% | 56,057 psi | 86% | 2930 fps | 99.7% |
| Norma URP | <<locked>> | 92% | 57,450 psi | 88% | 2848 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 55,172 psi | 85% | 2785 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 55,332 psi | 85% | 2904 fps | 98.1% |
| Ramshot Hunter | <<locked>> | 92% | 55,985 psi | 86% | 2848 fps | 99.9% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 49,487 psi | 76% | 2779 fps | 98.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,318 psi | 57% | 1762 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 55,898 psi | 86% | 2772 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 56,753 psi | 87% | 2877 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 54,926 psi | 85% | 2831 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 57,217 psi | 88% | 2917 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 45,281 psi | 70% | 2799 fps | 98.6% |
| Rottweil R 902 | <<locked>> | 82% | 55,782 psi | 86% | 2717 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 56,043 psi | 86% | 2766 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 57,522 psi | 88% | 2825 fps | 98.1% |
| Rottweil R 905 | <<locked>> | 98% | 58,218 psi | 90% | 2884 fps | 99.1% |
| Rottweil R 907 | <<locked>> | 90% | 58,595 psi | 90% | 2812 fps | 99.5% |
| Shooters World Long Rifle | <<locked>> | 90% | 57,087 psi | 88% | 2785 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 57,188 psi | 88% | 2756 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 58,479 psi | 90% | 2828 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 57,580 psi | 89% | 2825 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 58,479 psi | 90% | 2799 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 56,753 psi | 87% | 2651 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 56,594 psi | 87% | 2740 fps | 99.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 57,725 psi | 89% | 2881 fps | 99.1% |
| Somchem S335 | <<locked>> | 82% | 58,813 psi | 90% | 2687 fps | 100% |
| Somchem S355 | <<locked>> | 86% | 55,840 psi | 86% | 2762 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 55,637 psi | 86% | 2766 fps | 97% |
| Somchem S365 | <<locked>> | 94% | 56,942 psi | 88% | 2844 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 55,274 psi | 85% | 2808 fps | 99.3% |
| Vihtavuori N135 | <<locked>> | 82% | 56,376 psi | 87% | 2677 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 56,478 psi | 87% | 2694 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 57,116 psi | 88% | 2736 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 55,941 psi | 86% | 2792 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 54,462 psi | 84% | 2782 fps | 98.9% |
| Vihtavuori N540 | <<locked>> | 84% | 58,117 psi | 89% | 2736 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 58,465 psi | 90% | 2844 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 55,941 psi | 86% | 2854 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 56,202 psi | 86% | 2920 fps | 97.5% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 48,153 psi | 74% | 2772 fps | 96.1% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 55,390 psi | 85% | 2756 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 57,493 psi | 88% | 2867 fps | 99.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 48,791 psi | 75% | 2897 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 58,813 psi | 90% | 2805 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 55,405 psi | 85% | 2802 fps | 98.6% |
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% | 53,838 psi | 83% | 2644 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 51,126 psi | 79% | 2661 fps | 98.6% |
| Accurate 3100 | <<locked>> | 84% | 33,170 psi | 51% | 2392 fps | 95.8% |
| Accurate 4064 | <<locked>> | 80% | 51,010 psi | 78% | 2654 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 39,276 psi | 60% | 2539 fps | 99% |
| Accurate MAGPRO | <<locked>> | 96% | 51,372 psi | 79% | 2844 fps | 95.9% |
| ADI AR 2208 | <<locked>> | 80% | 47,790 psi | 74% | 2631 fps | 100% |
| ADI AR 2209 | <<locked>> | 86% | 40,393 psi | 62% | 2572 fps | 95.2% |
| ADI AR 2213 | <<locked>> | 94% | 46,992 psi | 72% | 2733 fps | 95.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 53,345 psi | 82% | 2848 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 48,631 psi | 75% | 2657 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 51,866 psi | 80% | 2723 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 38,000 psi | 58% | 2549 fps | 99.1% |
| Alliant Reloder-17 | <<locked>> | 80% | 43,221 psi | 66% | 2667 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 40,176 psi | 62% | 2569 fps | 95.3% |
| Alliant Reloder-22 | <<locked>> | 90% | 40,538 psi | 62% | 2621 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,963 psi | 43% | 2313 fps | 97.3% |
| Alliant Reloder-25 | <<locked>> | 88% | 31,618 psi | 49% | 2428 fps | 95.6% |
| Alliant Reloder-26 | 53.1 gr | 80% | 29,921 psi | 46% | 2421 fps | 95.7% |
| Bofors RP15 | <<locked>> | 92% | 39,987 psi | 62% | 2608 fps | 95.2% |
| Bofors RP3 | <<locked>> | 80% | 48,994 psi | 75% | 2667 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 40,538 psi | 62% | 2621 fps | 95.6% |
| Bofors RP7 | <<locked>> | 80% | 43,062 psi | 66% | 2552 fps | 97.2% |
| Hodgdon H1000 | <<locked>> | 98% | 42,989 psi | 66% | 2648 fps | 95.3% |
| Hodgdon H380 | <<locked>> | 80% | 49,400 psi | 76% | 2684 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 80% | 41,133 psi | 63% | 2585 fps | 97.3% |
| Hodgdon H4350 | <<locked>> | 80% | 43,903 psi | 68% | 2602 fps | 96.7% |
| Hodgdon H4831 | <<locked>> | 92% | 46,992 psi | 72% | 2684 fps | 95% |
| Hodgdon H4831 SC | <<locked>> | 94% | 49,342 psi | 76% | 2723 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 35,665 psi | 55% | 2444 fps | 99.5% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 53,896 psi | 83% | 2769 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 39,914 psi | 61% | 2680 fps | 95.8% |
| Hodgdon Superformance | <<locked>> | 80% | 40,089 psi | 62% | 2598 fps | 96.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,296 psi | 42% | 1535 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 54,360 psi | 84% | 2733 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 50,299 psi | 77% | 2664 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 52,634 psi | 81% | 2697 fps | 99.2% |
| IMR 4350 | <<locked>> | 80% | 38,566 psi | 59% | 2480 fps | 95.9% |
| IMR 4451 Enduron | <<locked>> | 80% | 44,396 psi | 68% | 2579 fps | 97.9% |
| IMR 4831 | <<locked>> | 80% | 37,710 psi | 58% | 2493 fps | 98.8% |
| IMR 4895 | <<locked>> | 80% | 53,200 psi | 82% | 2749 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 45,963 psi | 71% | 2628 fps | 95% |
| IMR 7828 SSC | <<locked>> | 94% | 44,831 psi | 69% | 2707 fps | 95.2% |
| Lovex S060 | <<locked>> | 80% | 54,839 psi | 84% | 2697 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 50,560 psi | 78% | 2657 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,916 psi | 64% | 2530 fps | 98.5% |
| Lovex S070 | <<locked>> | 80% | 40,292 psi | 62% | 2516 fps | 97.2% |
| Lovex S071 | <<locked>> | 88% | 32,285 psi | 50% | 2372 fps | 95.4% |
| Norma 201 | <<locked>> | 80% | 55,056 psi | 85% | 2717 fps | 100% |
| Norma 203B | <<locked>> | 80% | 51,213 psi | 79% | 2710 fps | 100% |
| Norma 204 | <<locked>> | 82% | 40,828 psi | 63% | 2562 fps | 95.2% |
| Norma MRP | 55.4 gr | 86% | 37,028 psi | 57% | 2572 fps | 95.9% |
| Norma URP | <<locked>> | 80% | 38,986 psi | 60% | 2533 fps | 98.9% |
| Ramshot Big Game | <<locked>> | 80% | 51,634 psi | 79% | 2736 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 44,469 psi | 68% | 2710 fps | 95.5% |
| Ramshot Hunter | <<locked>> | 80% | 37,695 psi | 58% | 2520 fps | 97.2% |
| Ramshot Magnum | <<locked>> | 94% | 39,581 psi | 61% | 2592 fps | 96% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,992 psi | 43% | 1578 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 49,269 psi | 76% | 2671 fps | 99.2% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 45,876 psi | 71% | 2717 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 39,073 psi | 60% | 2559 fps | 98.8% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 37,652 psi | 58% | 2562 fps | 98.2% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 36,666 psi | 56% | 2598 fps | 95.6% |
| Rottweil R 902 | <<locked>> | 80% | 52,446 psi | 81% | 2671 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 46,325 psi | 71% | 2621 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 44,802 psi | 69% | 2612 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 86% | 39,305 psi | 60% | 2552 fps | 95.2% |
| Rottweil R 907 | <<locked>> | 80% | 43,062 psi | 66% | 2552 fps | 97.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,916 psi | 64% | 2530 fps | 98.5% |
| Shooters World Precision | <<locked>> | 80% | 50,560 psi | 78% | 2657 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 40,292 psi | 62% | 2516 fps | 97.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 47,340 psi | 73% | 2671 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 54,810 psi | 84% | 2746 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 47,195 psi | 73% | 2520 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 41,031 psi | 63% | 2477 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 38,943 psi | 60% | 2549 fps | 95% |
| Somchem S335 | <<locked>> | 80% | 55,419 psi | 85% | 2644 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 46,398 psi | 71% | 2615 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 48,878 psi | 75% | 2657 fps | 95.5% |
| Somchem S365 | <<locked>> | 80% | 35,360 psi | 54% | 2490 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 37,362 psi | 57% | 2484 fps | 95.4% |
| Vihtavuori N135 | <<locked>> | 80% | 52,895 psi | 81% | 2631 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 53,113 psi | 82% | 2648 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 44,469 psi | 68% | 2549 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 40,306 psi | 62% | 2530 fps | 99.1% |
| Vihtavuori N165 | <<locked>> | 90% | 39,378 psi | 61% | 2520 fps | 95.7% |
| Vihtavuori N540 | <<locked>> | 80% | 51,285 psi | 79% | 2644 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 39,798 psi | 61% | 2533 fps | 98.9% |
| Vihtavuori N555 | <<locked>> | 80% | 31,009 psi | 48% | 2385 fps | 97.3% |
| Vihtavuori N560 | 59.3 gr | 92% | 45,992 psi | 71% | 2743 fps | 95.1% |
| Vihtavuori N565 | <<locked>> | 98% | 44,947 psi | 69% | 2713 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 39,204 psi | 60% | 2497 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 41,133 psi | 63% | 2585 fps | 97.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,729 psi | 38% | 2287 fps | 96.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 55,027 psi | 85% | 2753 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 41,901 psi | 64% | 2575 fps | 95.8% |
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 96 powders for .280 Ackley Improved loaded with the .284 | 160gr | Speer Magnum Tip Soft Point. Alliant Reloder-26 delivers the highest muzzle velocity at 2,976 fps; across all powders the maximum-charge window runs from 1,722 fps to 2,976 fps. Accurate 3100 gives the best case fill at 100 %, and 96 of the 96 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 1:12.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2213, Alliant Reloder-22 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, Norma MRP, Vihtavuori N560 rank at the top here: for .280 Ackley Improved with the .284 | 160gr | Speer Magnum Tip Soft Point 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.