Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 160gr | Speer Deep Curl 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% | 57,261 psi | 88% | 2690 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 58,320 psi | 90% | 2769 fps | 99.4% |
| Accurate 3100ᴾ | <<locked>> | 100% | 56,695 psi | 87% | 2818 fps | 99.9% |
| Accurate 4064 | <<locked>> | 84% | 57,667 psi | 89% | 2746 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 54,897 psi | 84% | 2808 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 55,100 psi | 85% | 2904 fps | 96.7% |
| ADI AR 2208 | <<locked>> | 86% | 57,392 psi | 88% | 2776 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 55,825 psi | 86% | 2854 fps | 98.7% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 57,305 psi | 88% | 2910 fps | 98% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 57,188 psi | 88% | 2904 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 58,450 psi | 90% | 2802 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 58,552 psi | 90% | 2822 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 55,767 psi | 86% | 2864 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 56,956 psi | 88% | 2881 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 55,129 psi | 85% | 2841 fps | 98.7% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 56,434 psi | 87% | 2904 fps | 99% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 53,127 psi | 82% | 2828 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 46,311 psi | 71% | 2769 fps | 99.7% |
| Alliant Reloder-26 | <<locked>> | 98% | 57,464 psi | 88% | 2972 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 51,517 psi | 79% | 2825 fps | 98.1% |
| Bofors RP3 | <<locked>> | 84% | 55,796 psi | 86% | 2769 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 56,434 psi | 87% | 2904 fps | 99% |
| Bofors RP7 | <<locked>> | 90% | 58,566 psi | 90% | 2808 fps | 99.5% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 45,861 psi | 71% | 2703 fps | 96.2% |
| Hodgdon H380 | <<locked>> | 84% | 56,202 psi | 86% | 2789 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 57,116 psi | 88% | 2861 fps | 99.7% |
| Hodgdon H4350 | <<locked>> | 88% | 56,681 psi | 87% | 2822 fps | 99% |
| Hodgdon H4831 | <<locked>> | 98% | 57,305 psi | 88% | 2851 fps | 97.3% |
| Hodgdon H4831 SC | <<locked>> | 98% | 56,072 psi | 86% | 2831 fps | 97.1% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 56,072 psi | 86% | 2785 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 57,551 psi | 89% | 2818 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 45,208 psi | 70% | 2799 fps | 97.6% |
| Hodgdon Superformance | <<locked>> | 90% | 57,653 psi | 89% | 2904 fps | 99.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,709 psi | 56% | 1722 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 57,740 psi | 89% | 2779 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,898 psi | 88% | 2759 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 55,912 psi | 86% | 2746 fps | 99.6% |
| IMR 4350 | <<locked>> | 92% | 56,217 psi | 86% | 2795 fps | 99.4% |
| IMR 4451 Enduron | <<locked>> | 88% | 56,507 psi | 87% | 2782 fps | 99.6% |
| IMR 4831 | <<locked>> | 92% | 55,419 psi | 85% | 2802 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 56,507 psi | 87% | 2799 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 58,639 psi | 90% | 2835 fps | 97.7% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 54,679 psi | 84% | 2881 fps | 97.6% |
| Lovex S060 | <<locked>> | 82% | 58,175 psi | 89% | 2743 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 57,145 psi | 88% | 2753 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 56,768 psi | 87% | 2779 fps | 100% |
| Lovex S070 | <<locked>> | 92% | 58,160 psi | 89% | 2822 fps | 99.8% |
| Lovex S071ᴾ | <<locked>> | 100% | 47,036 psi | 72% | 2671 fps | 99.2% |
| Norma 201 | <<locked>> | 82% | 58,436 psi | 90% | 2762 fps | 100% |
| Norma 203B | <<locked>> | 84% | 57,841 psi | 89% | 2808 fps | 100% |
| Norma 204 | <<locked>> | 92% | 56,971 psi | 88% | 2848 fps | 98.7% |
| Norma MRP | <<locked>> | 98% | 56,043 psi | 86% | 2930 fps | 99.7% |
| Norma URP | <<locked>> | 92% | 57,058 psi | 88% | 2841 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 55,158 psi | 85% | 2785 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 54,984 psi | 85% | 2897 fps | 98% |
| Ramshot Hunter | <<locked>> | 92% | 55,941 psi | 86% | 2848 fps | 99.9% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 49,182 psi | 76% | 2776 fps | 98.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,420 psi | 58% | 1765 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 55,854 psi | 86% | 2772 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 56,681 psi | 87% | 2874 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 58,798 psi | 90% | 2887 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 57,145 psi | 88% | 2917 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 45,266 psi | 70% | 2799 fps | 98.6% |
| Rottweil R 902 | <<locked>> | 82% | 55,709 psi | 86% | 2717 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 55,956 psi | 86% | 2766 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 57,493 psi | 88% | 2825 fps | 98% |
| Rottweil R 905 | <<locked>> | 98% | 58,218 psi | 90% | 2884 fps | 99.1% |
| Rottweil R 907 | <<locked>> | 90% | 58,566 psi | 90% | 2808 fps | 99.5% |
| Shooters World Long Rifle | <<locked>> | 90% | 56,768 psi | 87% | 2779 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 57,145 psi | 88% | 2753 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 58,160 psi | 89% | 2822 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 57,508 psi | 88% | 2825 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 58,146 psi | 89% | 2792 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 56,666 psi | 87% | 2648 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 56,289 psi | 87% | 2733 fps | 99.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 57,725 psi | 89% | 2877 fps | 99.1% |
| Somchem S335 | <<locked>> | 82% | 58,769 psi | 90% | 2684 fps | 100% |
| Somchem S355 | <<locked>> | 86% | 55,753 psi | 86% | 2759 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 55,666 psi | 86% | 2766 fps | 97% |
| Somchem S365 | <<locked>> | 94% | 56,913 psi | 88% | 2844 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 58,769 psi | 90% | 2858 fps | 99.6% |
| Vihtavuori N135 | <<locked>> | 82% | 56,289 psi | 87% | 2674 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 56,391 psi | 87% | 2690 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 57,072 psi | 88% | 2733 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 55,608 psi | 86% | 2785 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 54,476 psi | 84% | 2782 fps | 98.9% |
| Vihtavuori N540 | <<locked>> | 84% | 58,073 psi | 89% | 2736 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 58,450 psi | 90% | 2844 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 55,927 psi | 86% | 2858 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 56,217 psi | 86% | 2920 fps | 97.5% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 48,153 psi | 74% | 2772 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 55,042 psi | 85% | 2753 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 57,116 psi | 88% | 2861 fps | 99.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 48,689 psi | 75% | 2897 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 58,479 psi | 90% | 2802 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 55,056 psi | 85% | 2799 fps | 98.5% |
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% | 53,737 psi | 83% | 2644 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 51,082 psi | 79% | 2661 fps | 98.5% |
| Accurate 3100 | <<locked>> | 84% | 32,938 psi | 51% | 2385 fps | 95.6% |
| Accurate 4064 | <<locked>> | 80% | 50,966 psi | 78% | 2651 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 39,204 psi | 60% | 2536 fps | 99% |
| Accurate MAGPRO | <<locked>> | 96% | 51,358 psi | 79% | 2841 fps | 95.8% |
| ADI AR 2208 | <<locked>> | 80% | 47,747 psi | 73% | 2631 fps | 100% |
| ADI AR 2209 | <<locked>> | 86% | 40,364 psi | 62% | 2572 fps | 95.1% |
| ADI AR 2213 | <<locked>> | 94% | 46,731 psi | 72% | 2726 fps | 95.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 53,287 psi | 82% | 2848 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 48,559 psi | 75% | 2657 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 51,779 psi | 80% | 2723 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 37,956 psi | 58% | 2546 fps | 99.1% |
| Alliant Reloder-17 | <<locked>> | 80% | 43,134 psi | 66% | 2664 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 40,132 psi | 62% | 2569 fps | 95.2% |
| Alliant Reloder-22 | <<locked>> | 90% | 40,277 psi | 62% | 2615 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,920 psi | 43% | 2310 fps | 97.2% |
| Alliant Reloder-25 | <<locked>> | 88% | 31,604 psi | 49% | 2428 fps | 95.5% |
| Alliant Reloder-26 | 53 gr | 80% | 29,878 psi | 46% | 2418 fps | 95.6% |
| Bofors RP15 | <<locked>> | 92% | 39,740 psi | 61% | 2602 fps | 95.1% |
| Bofors RP3 | <<locked>> | 80% | 48,907 psi | 75% | 2667 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 40,277 psi | 62% | 2615 fps | 95.5% |
| Bofors RP7 | <<locked>> | 80% | 42,975 psi | 66% | 2549 fps | 97.2% |
| Hodgdon H1000 | <<locked>> | 98% | 42,728 psi | 66% | 2641 fps | 95.2% |
| Hodgdon H380 | <<locked>> | 80% | 49,095 psi | 76% | 2677 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 80% | 41,104 psi | 63% | 2582 fps | 97.3% |
| Hodgdon H4350 | <<locked>> | 80% | 43,845 psi | 67% | 2598 fps | 96.7% |
| Hodgdon H4831 | <<locked>> | 94% | 50,082 psi | 77% | 2736 fps | 95.9% |
| Hodgdon H4831 SC | <<locked>> | 94% | 49,008 psi | 75% | 2717 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 35,592 psi | 55% | 2441 fps | 99.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 53,838 psi | 83% | 2766 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 39,697 psi | 61% | 2674 fps | 95.7% |
| Hodgdon Superformance | <<locked>> | 80% | 39,827 psi | 61% | 2592 fps | 96.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,369 psi | 42% | 1535 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 54,317 psi | 84% | 2730 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 50,212 psi | 77% | 2661 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 52,605 psi | 81% | 2697 fps | 99.2% |
| IMR 4350 | <<locked>> | 80% | 38,508 psi | 59% | 2477 fps | 95.9% |
| IMR 4451 Enduron | <<locked>> | 80% | 44,309 psi | 68% | 2575 fps | 97.9% |
| IMR 4831 | <<locked>> | 80% | 37,434 psi | 58% | 2487 fps | 98.7% |
| IMR 4895 | <<locked>> | 80% | 53,127 psi | 82% | 2749 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 48,820 psi | 75% | 2677 fps | 95.7% |
| IMR 7828 SSC | <<locked>> | 94% | 44,570 psi | 69% | 2700 fps | 95.1% |
| Lovex S060 | <<locked>> | 80% | 54,752 psi | 84% | 2694 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 50,517 psi | 78% | 2657 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,872 psi | 64% | 2530 fps | 98.5% |
| Lovex S070 | <<locked>> | 80% | 40,045 psi | 62% | 2510 fps | 97.2% |
| Lovex S071 | <<locked>> | 88% | 32,213 psi | 50% | 2369 fps | 95.4% |
| Norma 201 | <<locked>> | 80% | 54,955 psi | 85% | 2713 fps | 100% |
| Norma 203B | <<locked>> | 80% | 51,140 psi | 79% | 2710 fps | 100% |
| Norma 204 | <<locked>> | 82% | 40,553 psi | 62% | 2556 fps | 95.1% |
| Norma MRP | 55.3 gr | 86% | 36,970 psi | 57% | 2569 fps | 95.8% |
| Norma URP | <<locked>> | 80% | 38,711 psi | 60% | 2526 fps | 98.8% |
| Ramshot Big Game | <<locked>> | 80% | 51,590 psi | 79% | 2733 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 44,469 psi | 68% | 2710 fps | 95.4% |
| Ramshot Hunter | <<locked>> | 80% | 37,652 psi | 58% | 2520 fps | 97.1% |
| Ramshot Magnum | <<locked>> | 94% | 39,552 psi | 61% | 2589 fps | 95.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,862 psi | 43% | 1572 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 49,240 psi | 76% | 2667 fps | 99.2% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 45,818 psi | 70% | 2713 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 38,812 psi | 60% | 2552 fps | 98.7% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 37,579 psi | 58% | 2562 fps | 98.2% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 36,666 psi | 56% | 2595 fps | 95.6% |
| Rottweil R 902 | <<locked>> | 80% | 52,373 psi | 81% | 2667 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 46,021 psi | 71% | 2615 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 44,527 psi | 69% | 2605 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 86% | 39,233 psi | 60% | 2552 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 42,975 psi | 66% | 2549 fps | 97.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,872 psi | 64% | 2530 fps | 98.5% |
| Shooters World Precision | <<locked>> | 80% | 50,517 psi | 78% | 2657 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 40,045 psi | 62% | 2510 fps | 97.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 47,282 psi | 73% | 2671 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 54,723 psi | 84% | 2743 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 47,152 psi | 73% | 2520 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 41,017 psi | 63% | 2474 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 38,870 psi | 60% | 2546 fps | 95% |
| Somchem S335 | <<locked>> | 80% | 55,376 psi | 85% | 2641 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 46,296 psi | 71% | 2615 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 48,573 psi | 75% | 2651 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 35,288 psi | 54% | 2487 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 37,318 psi | 57% | 2480 fps | 95.4% |
| Vihtavuori N135 | <<locked>> | 80% | 52,808 psi | 81% | 2628 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 52,765 psi | 81% | 2644 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 44,164 psi | 68% | 2543 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 40,248 psi | 62% | 2530 fps | 99.1% |
| Vihtavuori N165 | <<locked>> | 90% | 39,117 psi | 60% | 2513 fps | 95.6% |
| Vihtavuori N540 | <<locked>> | 80% | 50,966 psi | 78% | 2638 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 39,566 psi | 61% | 2530 fps | 98.8% |
| Vihtavuori N555 | <<locked>> | 80% | 30,922 psi | 48% | 2382 fps | 97.3% |
| Vihtavuori N560 | 59.1 gr | 92% | 45,701 psi | 70% | 2736 fps | 95% |
| Vihtavuori N565 | <<locked>> | 98% | 44,889 psi | 69% | 2713 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 39,146 psi | 60% | 2493 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 41,104 psi | 63% | 2582 fps | 97.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,685 psi | 38% | 2287 fps | 96.1% |
| Winchester StaBALL Match | <<locked>> | 80% | 54,723 psi | 84% | 2749 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 41,858 psi | 64% | 2575 fps | 95.7% |
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 103 powders for .280 Ackley Improved loaded with the .284 | 160gr | Speer Deep Curl Soft Point. Alliant Reloder-26 delivers the highest muzzle velocity at 2,972 fps; across all powders the maximum-charge window runs from 1,722 fps to 2,972 fps. Accurate 3100 gives the best case fill at 100 %, and 103 of the 103 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 50–90 %, 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, ADI AR 2217 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 Deep Curl Soft Point they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2217, Baschieri & Pellagri 109, Norma 217 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.