Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 160gr | Barnes MRX BT bullet and 100 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 70, Alliant Reloder-26 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% | 55,100 psi | 85% | 2667 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 56,927 psi | 88% | 2753 fps | 99.2% |
| Accurate 3100ᴾ | <<locked>> | 100% | 54,563 psi | 84% | 2792 fps | 99.8% |
| Accurate 4064 | <<locked>> | 84% | 55,680 psi | 86% | 2726 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 56,826 psi | 87% | 2841 fps | 100% |
| Accurate MAGPROᴾ | <<locked>> | 100% | 57,290 psi | 88% | 2943 fps | 97.1% |
| ADI AR 2206H | <<locked>> | 82% | 58,421 psi | 90% | 2805 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 56,115 psi | 86% | 2762 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 58,204 psi | 90% | 2890 fps | 99% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 55,709 psi | 86% | 2887 fps | 97.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 55,753 psi | 86% | 2887 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 56,985 psi | 88% | 2785 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 57,087 psi | 88% | 2805 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 57,711 psi | 89% | 2894 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 55,419 psi | 85% | 2864 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 57,334 psi | 88% | 2877 fps | 98.9% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 54,636 psi | 84% | 2881 fps | 98.7% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 51,547 psi | 79% | 2808 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,672 psi | 69% | 2743 fps | 99.5% |
| Alliant Reloder-26 | <<locked>> | 98% | 55,448 psi | 85% | 2949 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 58,595 psi | 90% | 2828 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 50,082 psi | 77% | 2805 fps | 97.8% |
| Bofors RP3 | <<locked>> | 86% | 57,725 psi | 89% | 2799 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 54,636 psi | 84% | 2881 fps | 98.7% |
| Bofors RP7 | <<locked>> | 90% | 57,159 psi | 88% | 2792 fps | 99.4% |
| Hodgdon H380 | <<locked>> | 86% | 58,247 psi | 90% | 2822 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 55,390 psi | 85% | 2838 fps | 99.6% |
| Hodgdon H4350 | <<locked>> | 88% | 55,361 psi | 85% | 2802 fps | 98.8% |
| Hodgdon H4831 | <<locked>> | 98% | 55,695 psi | 86% | 2828 fps | 97% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 58,552 psi | 90% | 2871 fps | 97.5% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 58,291 psi | 90% | 2818 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 55,825 psi | 86% | 2799 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 43,845 psi | 67% | 2776 fps | 97.2% |
| Hodgdon Superformance | <<locked>> | 90% | 55,898 psi | 86% | 2881 fps | 99.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,332 psi | 56% | 1716 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 56,463 psi | 87% | 2762 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 55,506 psi | 85% | 2746 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 58,160 psi | 89% | 2785 fps | 99.7% |
| IMR 4350 | <<locked>> | 94% | 58,175 psi | 89% | 2825 fps | 99.5% |
| IMR 4451 Enduron | <<locked>> | 90% | 58,784 psi | 90% | 2818 fps | 99.7% |
| IMR 4831 | <<locked>> | 94% | 57,406 psi | 88% | 2831 fps | 100% |
| IMR 4895 | <<locked>> | 84% | 58,610 psi | 90% | 2831 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 57,435 psi | 88% | 2818 fps | 97.5% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 53,055 psi | 82% | 2858 fps | 97.3% |
| Lovex S060 | <<locked>> | 82% | 56,942 psi | 88% | 2730 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 55,608 psi | 86% | 2736 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 55,303 psi | 85% | 2762 fps | 99.9% |
| Lovex S070 | <<locked>> | 92% | 56,637 psi | 87% | 2805 fps | 99.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,252 psi | 70% | 2644 fps | 98.9% |
| Norma 201 | <<locked>> | 82% | 56,869 psi | 87% | 2746 fps | 100% |
| Norma 202 | <<locked>> | 82% | 57,841 psi | 89% | 2743 fps | 100% |
| Norma 203B | <<locked>> | 84% | 56,362 psi | 87% | 2792 fps | 100% |
| Norma 204 | <<locked>> | 92% | 55,608 psi | 86% | 2828 fps | 98.5% |
| Norma MRPᴾ | <<locked>> | 100% | 58,305 psi | 90% | 2966 fps | 99.8% |
| Norma URP | <<locked>> | 92% | 55,564 psi | 85% | 2825 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 57,508 psi | 88% | 2822 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 53,229 psi | 82% | 2871 fps | 97.7% |
| Ramshot Hunter | <<locked>> | 94% | 58,117 psi | 89% | 2881 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 47,456 psi | 73% | 2746 fps | 98.1% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,985 psi | 57% | 1759 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 58,276 psi | 90% | 2812 fps | 99.9% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 58,407 psi | 90% | 2874 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 54,868 psi | 84% | 2854 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 56,855 psi | 87% | 2864 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 55,463 psi | 85% | 2894 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,642 psi | 67% | 2766 fps | 98.2% |
| Rottweil R 902 | <<locked>> | 84% | 57,653 psi | 89% | 2749 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 57,885 psi | 89% | 2795 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 55,927 psi | 86% | 2802 fps | 97.7% |
| Rottweil R 905 | <<locked>> | 98% | 56,434 psi | 87% | 2861 fps | 98.9% |
| Rottweil R 907 | <<locked>> | 90% | 57,159 psi | 88% | 2792 fps | 99.4% |
| Shooters World Long Rifle | <<locked>> | 90% | 55,303 psi | 85% | 2762 fps | 99.9% |
| Shooters World Precision | <<locked>> | 84% | 55,608 psi | 86% | 2736 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 56,637 psi | 87% | 2805 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 56,101 psi | 86% | 2808 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 56,768 psi | 87% | 2776 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 57,856 psi | 89% | 2677 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 58,711 psi | 90% | 2677 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 58,566 psi | 90% | 2769 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 55,956 psi | 86% | 2858 fps | 98.8% |
| Somchem S335 | <<locked>> | 82% | 57,334 psi | 88% | 2674 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 57,711 psi | 89% | 2792 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 57,841 psi | 89% | 2802 fps | 97.3% |
| Somchem S365 | <<locked>> | 96% | 58,726 psi | 90% | 2871 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 56,927 psi | 88% | 2835 fps | 99.4% |
| Vihtavuori N133 | <<locked>> | 82% | 58,450 psi | 90% | 2657 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 58,044 psi | 89% | 2703 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 58,537 psi | 90% | 2723 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 55,608 psi | 86% | 2720 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 57,754 psi | 89% | 2818 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 52,750 psi | 81% | 2759 fps | 98.7% |
| Vihtavuori N540 | <<locked>> | 84% | 56,376 psi | 87% | 2717 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 56,652 psi | 87% | 2822 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 57,508 psi | 88% | 2881 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 58,508 psi | 90% | 2956 fps | 97.9% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 57,580 psi | 89% | 2785 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 55,709 psi | 86% | 2844 fps | 99.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,630 psi | 72% | 2867 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 57,043 psi | 88% | 2785 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 57,464 psi | 88% | 2835 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% | 51,590 psi | 79% | 2621 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 49,748 psi | 77% | 2641 fps | 98.3% |
| Accurate 3100 | <<locked>> | 86% | 33,475 psi | 51% | 2405 fps | 95.8% |
| Accurate 4064 | <<locked>> | 80% | 48,936 psi | 75% | 2631 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 37,434 psi | 58% | 2507 fps | 98.6% |
| Accurate MAGPRO | <<locked>> | 96% | 49,516 psi | 76% | 2815 fps | 95.3% |
| ADI AR 2206H | <<locked>> | 80% | 54,868 psi | 84% | 2756 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 46,470 psi | 71% | 2612 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 88% | 41,713 psi | 64% | 2605 fps | 95.6% |
| ADI AR 2213 | <<locked>> | 94% | 45,440 psi | 70% | 2707 fps | 95.2% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 51,866 psi | 80% | 2828 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,094 psi | 72% | 2638 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,328 psi | 77% | 2707 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,637 psi | 56% | 2520 fps | 98.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 41,713 psi | 64% | 2644 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 41,423 psi | 64% | 2598 fps | 95.6% |
| Alliant Reloder-22 | <<locked>> | 92% | 41,481 psi | 64% | 2644 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 26,585 psi | 41% | 2277 fps | 96.5% |
| Alliant Reloder-25 | <<locked>> | 90% | 32,285 psi | 50% | 2451 fps | 95.9% |
| Alliant Reloder-26 | 54 gr | 82% | 30,530 psi | 47% | 2444 fps | 96% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 54,810 psi | 84% | 2776 fps | 100% |
| Bofors RP15 | <<locked>> | 94% | 40,901 psi | 63% | 2631 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 47,239 psi | 73% | 2644 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 41,481 psi | 64% | 2644 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 41,626 psi | 64% | 2526 fps | 96.8% |
| Hodgdon H380 | <<locked>> | 80% | 47,587 psi | 73% | 2657 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 80% | 39,682 psi | 61% | 2559 fps | 96.9% |
| Hodgdon H4350 | <<locked>> | 80% | 42,569 psi | 65% | 2579 fps | 96.3% |
| Hodgdon H4831 | <<locked>> | 94% | 48,544 psi | 75% | 2710 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 94% | 47,747 psi | 73% | 2697 fps | 95.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,156 psi | 53% | 2415 fps | 99.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 52,417 psi | 81% | 2753 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 38,334 psi | 59% | 2644 fps | 95% |
| Hodgdon Superformance | 54.3 gr | 80% | 38,508 psi | 59% | 2566 fps | 96.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,151 psi | 42% | 1532 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,026 psi | 82% | 2713 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 48,892 psi | 75% | 2644 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,387 psi | 79% | 2680 fps | 99.1% |
| IMR 4350 | <<locked>> | 80% | 37,246 psi | 57% | 2454 fps | 95.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,120 psi | 66% | 2556 fps | 97.6% |
| IMR 4831 | <<locked>> | 80% | 36,114 psi | 56% | 2464 fps | 98.4% |
| IMR 4895 | <<locked>> | 80% | 51,648 psi | 79% | 2733 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 47,369 psi | 73% | 2654 fps | 95.3% |
| IMR 7828 SSC | <<locked>> | 96% | 46,224 psi | 71% | 2736 fps | 95.5% |
| Lovex S060 | <<locked>> | 80% | 53,548 psi | 82% | 2680 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 48,979 psi | 75% | 2638 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 40,422 psi | 62% | 2507 fps | 98.2% |
| Lovex S070 | <<locked>> | 80% | 38,580 psi | 59% | 2484 fps | 96.7% |
| Lovex S071 | <<locked>> | 90% | 32,532 psi | 50% | 2382 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 53,359 psi | 82% | 2697 fps | 100% |
| Norma 202 | <<locked>> | 80% | 54,302 psi | 84% | 2694 fps | 100% |
| Norma 203B | <<locked>> | 80% | 49,647 psi | 76% | 2690 fps | 100% |
| Norma 204 | <<locked>> | 84% | 42,148 psi | 65% | 2595 fps | 95.6% |
| Norma MRP | <<locked>> | 86% | 35,375 psi | 54% | 2536 fps | 95.1% |
| Norma URP | <<locked>> | 80% | 37,260 psi | 57% | 2500 fps | 98.5% |
| Ramshot Big Game | <<locked>> | 80% | 50,169 psi | 77% | 2717 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 46,108 psi | 71% | 2746 fps | 95.9% |
| Ramshot Hunter | <<locked>> | 80% | 36,274 psi | 56% | 2493 fps | 96.7% |
| Ramshot Magnum | <<locked>> | 94% | 37,956 psi | 58% | 2559 fps | 95.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,586 psi | 42% | 1568 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 47,630 psi | 73% | 2644 fps | 99% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 54,694 psi | 84% | 2822 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,367 psi | 68% | 2694 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,260 psi | 57% | 2526 fps | 98.3% |
| ReloadSwiss RS 70 | 52.2 gr | 80% | 36,289 psi | 56% | 2536 fps | 97.8% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 37,666 psi | 58% | 2628 fps | 96% |
| Rottweil R 902 | <<locked>> | 80% | 50,821 psi | 78% | 2651 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 44,367 psi | 68% | 2592 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 46,137 psi | 71% | 2641 fps | 95.6% |
| Rottweil R 905 | <<locked>> | 88% | 40,466 psi | 62% | 2582 fps | 95.5% |
| Rottweil R 907 | <<locked>> | 80% | 41,626 psi | 64% | 2526 fps | 96.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,422 psi | 62% | 2507 fps | 98.2% |
| Shooters World Precision | <<locked>> | 80% | 48,979 psi | 75% | 2638 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 38,580 psi | 59% | 2484 fps | 96.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,876 psi | 71% | 2651 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 53,403 psi | 82% | 2730 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 54,230 psi | 83% | 2628 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 45,861 psi | 71% | 2503 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 39,581 psi | 61% | 2451 fps | 96.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 40,089 psi | 62% | 2575 fps | 95.4% |
| Somchem S335 | <<locked>> | 80% | 53,940 psi | 83% | 2628 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 44,788 psi | 69% | 2592 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 47,297 psi | 73% | 2631 fps | 95% |
| Somchem S365 | <<locked>> | 80% | 33,750 psi | 52% | 2461 fps | 99.8% |
| Somchem S385 | <<locked>> | 86% | 38,261 psi | 59% | 2510 fps | 95.7% |
| Vihtavuori N133 | <<locked>> | 80% | 54,868 psi | 84% | 2612 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 51,213 psi | 79% | 2615 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 51,343 psi | 79% | 2628 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 42,699 psi | 66% | 2523 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 38,841 psi | 60% | 2503 fps | 98.8% |
| Vihtavuori N165 | <<locked>> | 90% | 37,739 psi | 58% | 2490 fps | 95.1% |
| Vihtavuori N540 | <<locked>> | 80% | 49,574 psi | 76% | 2621 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,087 psi | 59% | 2503 fps | 98.5% |
| Vihtavuori N555 | <<locked>> | 80% | 29,298 psi | 45% | 2349 fps | 96.6% |
| Vihtavuori N560 | <<locked>> | 94% | 47,282 psi | 73% | 2769 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 37,913 psi | 58% | 2477 fps | 99.8% |
| Winchester 760 | <<locked>> | 80% | 39,682 psi | 61% | 2559 fps | 96.9% |
| Winchester StaBALL HD | <<locked>> | 82% | 24,932 psi | 38% | 2303 fps | 96.3% |
| Winchester StaBALL Match | <<locked>> | 80% | 53,287 psi | 82% | 2733 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 40,480 psi | 62% | 2552 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 107 powders for .280 Ackley Improved loaded with the .284 | 160gr | Barnes MRX BT. Norma MRP delivers the highest muzzle velocity at 2,966 fps; across all powders the maximum-charge window runs from 1,716 fps to 2,966 fps. Accurate 3100 gives the best case fill at 100 %, and 107 of the 107 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 47–90 %, 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. ReloadSwiss RS 70, Alliant Reloder-26, Hodgdon Superformance rank at the top here: for .280 Ackley Improved with the .284 | 160gr | Barnes MRX BT 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.