Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 160gr | Nosler CT FailSafe bullet and 99 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 Hodgdon Superformance.
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% | 55,999 psi | 86% | 2667 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 57,101 psi | 88% | 2743 fps | 99.2% |
| Accurate 3100ᴾ | <<locked>> | 100% | 55,274 psi | 85% | 2792 fps | 99.8% |
| Accurate 4064 | <<locked>> | 84% | 56,492 psi | 87% | 2723 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 57,276 psi | 88% | 2835 fps | 100% |
| Accurate MAGPROᴾ | <<locked>> | 100% | 57,479 psi | 88% | 2933 fps | 97% |
| ADI AR 2206H | <<locked>> | 82% | 58,697 psi | 90% | 2799 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 56,376 psi | 87% | 2756 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 58,102 psi | 89% | 2881 fps | 98.9% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 55,782 psi | 86% | 2877 fps | 97.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 55,738 psi | 86% | 2877 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 57,334 psi | 88% | 2779 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 57,464 psi | 88% | 2802 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 58,088 psi | 89% | 2890 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 55,579 psi | 86% | 2858 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 57,595 psi | 89% | 2871 fps | 98.9% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 54,708 psi | 84% | 2874 fps | 98.6% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 51,909 psi | 80% | 2805 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,962 psi | 69% | 2736 fps | 99.5% |
| Alliant Reloder-26 | <<locked>> | 98% | 55,622 psi | 86% | 2943 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 50,198 psi | 77% | 2799 fps | 97.8% |
| Bofors RP3 | <<locked>> | 86% | 58,320 psi | 90% | 2795 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 54,708 psi | 84% | 2874 fps | 98.6% |
| Bofors RP7 | <<locked>> | 90% | 57,348 psi | 88% | 2785 fps | 99.4% |
| Hodgdon H380 | <<locked>> | 86% | 58,784 psi | 90% | 2818 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 55,927 psi | 86% | 2838 fps | 99.6% |
| Hodgdon H4350 | <<locked>> | 88% | 55,434 psi | 85% | 2792 fps | 98.8% |
| Hodgdon H4831 | <<locked>> | 98% | 56,028 psi | 86% | 2825 fps | 97% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 58,566 psi | 90% | 2861 fps | 97.4% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 58,494 psi | 90% | 2812 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 56,173 psi | 86% | 2795 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 44,121 psi | 68% | 2769 fps | 97.1% |
| Hodgdon Superformance | <<locked>> | 90% | 55,927 psi | 86% | 2871 fps | 99.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,506 psi | 56% | 1709 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 56,942 psi | 88% | 2762 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 55,782 psi | 86% | 2740 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 58,392 psi | 90% | 2776 fps | 99.7% |
| IMR 4350 | <<locked>> | 94% | 58,349 psi | 90% | 2818 fps | 99.5% |
| IMR 4451 Enduron | <<locked>> | 88% | 55,579 psi | 86% | 2762 fps | 99.4% |
| IMR 4831 | <<locked>> | 94% | 57,754 psi | 89% | 2825 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 55,347 psi | 85% | 2776 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 57,377 psi | 88% | 2808 fps | 97.4% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 53,142 psi | 82% | 2848 fps | 97.2% |
| Lovex S060 | <<locked>> | 82% | 57,377 psi | 88% | 2723 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 55,999 psi | 86% | 2730 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 55,840 psi | 86% | 2759 fps | 99.9% |
| Lovex S070 | <<locked>> | 92% | 56,985 psi | 88% | 2799 fps | 99.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,905 psi | 71% | 2648 fps | 98.9% |
| Norma 201 | <<locked>> | 82% | 57,319 psi | 88% | 2740 fps | 100% |
| Norma 202 | <<locked>> | 82% | 58,102 psi | 89% | 2736 fps | 100% |
| Norma 203B | <<locked>> | 84% | 56,753 psi | 87% | 2785 fps | 100% |
| Norma 204 | <<locked>> | 92% | 55,535 psi | 85% | 2818 fps | 98.4% |
| Norma MRPᴾ | <<locked>> | 100% | 58,407 psi | 90% | 2956 fps | 99.8% |
| Norma URP | <<locked>> | 92% | 55,782 psi | 86% | 2818 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 57,609 psi | 89% | 2812 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 53,722 psi | 83% | 2867 fps | 97.6% |
| Ramshot Hunter | <<locked>> | 94% | 58,392 psi | 90% | 2877 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 47,790 psi | 74% | 2743 fps | 98% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,217 psi | 57% | 1752 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 58,436 psi | 90% | 2802 fps | 99.9% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 58,769 psi | 90% | 2871 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 55,245 psi | 85% | 2851 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 57,232 psi | 88% | 2861 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 55,724 psi | 86% | 2890 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,830 psi | 67% | 2759 fps | 98.1% |
| Rottweil R 902 | <<locked>> | 84% | 58,088 psi | 89% | 2743 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 58,479 psi | 90% | 2792 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 56,130 psi | 86% | 2795 fps | 97.7% |
| Rottweil R 905 | <<locked>> | 98% | 56,739 psi | 87% | 2854 fps | 98.9% |
| Rottweil R 907 | <<locked>> | 90% | 57,348 psi | 88% | 2785 fps | 99.4% |
| Shooters World Long Rifle | <<locked>> | 90% | 55,840 psi | 86% | 2759 fps | 99.9% |
| Shooters World Precision | <<locked>> | 84% | 55,999 psi | 86% | 2730 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 56,985 psi | 88% | 2799 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 56,188 psi | 86% | 2802 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 57,087 psi | 88% | 2772 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 58,030 psi | 89% | 2667 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 55,622 psi | 86% | 2628 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 55,506 psi | 85% | 2713 fps | 99.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 56,246 psi | 87% | 2851 fps | 98.8% |
| Somchem S335 | <<locked>> | 82% | 57,696 psi | 89% | 2667 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 58,204 psi | 90% | 2785 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 57,986 psi | 89% | 2792 fps | 97.2% |
| Somchem S365 | <<locked>> | 94% | 55,230 psi | 85% | 2822 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 57,421 psi | 88% | 2831 fps | 99.4% |
| Vihtavuori N133 | <<locked>> | 82% | 58,537 psi | 90% | 2648 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 58,653 psi | 90% | 2700 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 55,303 psi | 85% | 2671 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 56,057 psi | 86% | 2717 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 57,943 psi | 89% | 2812 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 53,156 psi | 82% | 2756 fps | 98.6% |
| Vihtavuori N540 | <<locked>> | 84% | 56,797 psi | 87% | 2713 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 56,956 psi | 88% | 2818 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 58,015 psi | 89% | 2881 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 58,624 psi | 90% | 2949 fps | 97.8% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 57,856 psi | 89% | 2782 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 55,927 psi | 86% | 2838 fps | 99.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,775 psi | 72% | 2864 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 57,406 psi | 88% | 2779 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 57,580 psi | 89% | 2828 fps | 98.8% |
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% | 52,721 psi | 81% | 2625 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 50,125 psi | 77% | 2635 fps | 98.3% |
| Accurate 3100 | <<locked>> | 84% | 32,082 psi | 49% | 2362 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 49,980 psi | 77% | 2635 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,130 psi | 59% | 2510 fps | 98.7% |
| Accurate MAGPRO | <<locked>> | 96% | 49,777 psi | 77% | 2808 fps | 95.3% |
| ADI AR 2206H | <<locked>> | 80% | 55,172 psi | 85% | 2749 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 46,949 psi | 72% | 2608 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 88% | 41,959 psi | 65% | 2598 fps | 95.5% |
| ADI AR 2213 | <<locked>> | 94% | 45,788 psi | 70% | 2700 fps | 95.1% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 52,185 psi | 80% | 2825 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,456 psi | 73% | 2631 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,662 psi | 78% | 2700 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 37,188 psi | 57% | 2523 fps | 98.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 42,134 psi | 65% | 2641 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 41,655 psi | 64% | 2595 fps | 95.6% |
| Alliant Reloder-22 | <<locked>> | 92% | 41,887 psi | 64% | 2644 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,296 psi | 42% | 2287 fps | 96.8% |
| Alliant Reloder-25 | <<locked>> | 90% | 32,750 psi | 50% | 2454 fps | 96% |
| Alliant Reloder-26 | 53.1 gr | 82% | 31,082 psi | 48% | 2451 fps | 96.1% |
| Bofors RP15 | <<locked>> | 94% | 41,321 psi | 64% | 2631 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 47,805 psi | 74% | 2644 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 41,887 psi | 64% | 2644 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 42,047 psi | 65% | 2523 fps | 96.8% |
| Hodgdon H380 | <<locked>> | 80% | 48,312 psi | 74% | 2661 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 80% | 40,118 psi | 62% | 2556 fps | 96.9% |
| Hodgdon H4350 | <<locked>> | 80% | 42,873 psi | 66% | 2572 fps | 96.3% |
| Hodgdon H4831 | <<locked>> | 94% | 48,820 psi | 75% | 2707 fps | 95.3% |
| Hodgdon H4831 SC | <<locked>> | 94% | 48,008 psi | 74% | 2694 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,577 psi | 53% | 2415 fps | 99.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 52,721 psi | 81% | 2746 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 38,827 psi | 60% | 2644 fps | 95% |
| Hodgdon Superformance | 53.4 gr | 80% | 38,841 psi | 60% | 2562 fps | 96.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,209 psi | 42% | 1526 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,476 psi | 82% | 2710 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,356 psi | 76% | 2641 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,634 psi | 79% | 2674 fps | 99% |
| IMR 4350 | <<locked>> | 80% | 37,637 psi | 58% | 2451 fps | 95.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,395 psi | 67% | 2552 fps | 97.5% |
| IMR 4831 | <<locked>> | 80% | 36,651 psi | 56% | 2464 fps | 98.4% |
| IMR 4895 | <<locked>> | 80% | 51,967 psi | 80% | 2726 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 47,601 psi | 73% | 2648 fps | 95.2% |
| IMR 7828 SSC | <<locked>> | 96% | 46,572 psi | 72% | 2730 fps | 95.5% |
| Lovex S060 | <<locked>> | 80% | 53,940 psi | 83% | 2674 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,661 psi | 76% | 2638 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,118 psi | 63% | 2507 fps | 98.3% |
| Lovex S070 | <<locked>> | 80% | 39,320 psi | 60% | 2490 fps | 96.8% |
| Lovex S071 | <<locked>> | 90% | 33,344 psi | 51% | 2392 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 54,099 psi | 83% | 2694 fps | 100% |
| Norma 202 | <<locked>> | 80% | 54,563 psi | 84% | 2687 fps | 100% |
| Norma 203B | <<locked>> | 80% | 50,009 psi | 77% | 2687 fps | 100% |
| Norma 204 | <<locked>> | 84% | 42,583 psi | 66% | 2592 fps | 95.6% |
| Norma MRP | <<locked>> | 86% | 35,984 psi | 55% | 2543 fps | 95.3% |
| Norma URP | <<locked>> | 80% | 37,898 psi | 58% | 2507 fps | 98.6% |
| Ramshot Big Game | <<locked>> | 80% | 50,531 psi | 78% | 2713 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 46,586 psi | 72% | 2743 fps | 95.9% |
| Ramshot Hunter | <<locked>> | 80% | 36,753 psi | 57% | 2493 fps | 96.7% |
| Ramshot Magnum | <<locked>> | 94% | 38,551 psi | 59% | 2559 fps | 95.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,905 psi | 43% | 1565 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 48,066 psi | 74% | 2638 fps | 99% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 55,042 psi | 85% | 2818 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,759 psi | 69% | 2694 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,811 psi | 58% | 2526 fps | 98.4% |
| ReloadSwiss RS 70 | 51.4 gr | 80% | 36,782 psi | 57% | 2536 fps | 97.9% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 38,319 psi | 59% | 2631 fps | 96.1% |
| Rottweil R 902 | <<locked>> | 80% | 51,517 psi | 79% | 2648 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 45,150 psi | 69% | 2595 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 46,572 psi | 72% | 2638 fps | 95.6% |
| Rottweil R 905 | <<locked>> | 88% | 40,741 psi | 63% | 2579 fps | 95.5% |
| Rottweil R 907 | <<locked>> | 80% | 42,047 psi | 65% | 2523 fps | 96.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,118 psi | 63% | 2507 fps | 98.3% |
| Shooters World Precision | <<locked>> | 80% | 49,661 psi | 76% | 2638 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 39,320 psi | 60% | 2490 fps | 96.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 46,253 psi | 71% | 2648 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 53,679 psi | 83% | 2723 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 54,708 psi | 84% | 2625 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,311 psi | 71% | 2500 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,089 psi | 62% | 2451 fps | 96.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 40,364 psi | 62% | 2572 fps | 95.3% |
| Somchem S335 | <<locked>> | 80% | 54,549 psi | 84% | 2625 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 45,484 psi | 70% | 2595 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 47,674 psi | 73% | 2628 fps | 95% |
| Somchem S365 | <<locked>> | 80% | 34,272 psi | 53% | 2464 fps | 99.8% |
| Somchem S385 | <<locked>> | 84% | 36,448 psi | 56% | 2457 fps | 95% |
| Vihtavuori N133 | <<locked>> | 80% | 55,259 psi | 85% | 2608 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 51,793 psi | 80% | 2612 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 51,924 psi | 80% | 2625 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,366 psi | 67% | 2526 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 39,276 psi | 60% | 2503 fps | 98.8% |
| Vihtavuori N165 | <<locked>> | 90% | 38,116 psi | 59% | 2487 fps | 95.1% |
| Vihtavuori N540 | <<locked>> | 80% | 50,227 psi | 77% | 2621 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,827 psi | 60% | 2507 fps | 98.6% |
| Vihtavuori N555 | <<locked>> | 80% | 30,124 psi | 46% | 2362 fps | 96.9% |
| Vihtavuori N560 | <<locked>> | 94% | 47,674 psi | 73% | 2769 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,377 psi | 59% | 2477 fps | 99.8% |
| Winchester 760 | <<locked>> | 80% | 40,118 psi | 62% | 2556 fps | 96.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,076 psi | 37% | 2254 fps | 95.3% |
| Winchester StaBALL Match | <<locked>> | 80% | 53,664 psi | 83% | 2730 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 40,872 psi | 63% | 2549 fps | 95.3% |
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 106 powders for .280 Ackley Improved loaded with the .284 | 160gr | Nosler CT FailSafe. Norma MRP delivers the highest muzzle velocity at 2,956 fps; across all powders the maximum-charge window runs from 1,709 fps to 2,956 fps. Accurate 3100 gives the best case fill at 100 %, and 106 of the 106 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 48–90 %, leaving at least 10 % headroom. The 160.0 gr projectile in 0.284" calls for a 1:11.0 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, Hodgdon Superformance rank at the top here: for .280 Ackley Improved with the .284 | 160gr | Nosler CT FailSafe they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2217, Baschieri & Pellagri 109, Bofors RP30 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.