Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 174gr | Prvi Partizan SP bullet and 90 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N560, Norma MRP and Accurate MAGPRO.
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.
A valid access license is required to use the Personalized Load Calculator.
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 2700 | <<locked>> | 82% | 56,637 psi | 87% | 2635 fps | 99.6% |
| Accurate 3100 | <<locked>> | 98% | 55,738 psi | 86% | 2694 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 56,565 psi | 87% | 2608 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 57,783 psi | 89% | 2730 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 57,943 psi | 89% | 2835 fps | 98% |
| ADI AR 2208 | <<locked>> | 84% | 56,144 psi | 86% | 2644 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 58,479 psi | 90% | 2782 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 98% | 55,854 psi | 86% | 2779 fps | 98.5% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 38,595 psi | 59% | 2523 fps | 97.7% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 58,595 psi | 90% | 2776 fps | 99.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 57,058 psi | 88% | 2661 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 57,406 psi | 88% | 2687 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 58,276 psi | 90% | 2776 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 55,970 psi | 86% | 2746 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 57,783 psi | 89% | 2766 fps | 99.4% |
| Alliant Reloder-22 | <<locked>> | 98% | 55,274 psi | 85% | 2776 fps | 99.3% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 56,217 psi | 86% | 2749 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 48,646 psi | 75% | 2700 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 56,492 psi | 87% | 2838 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 58,378 psi | 90% | 2743 fps | 96.1% |
| Bofors RP15ᴾ | <<locked>> | 100% | 54,172 psi | 83% | 2756 fps | 99.1% |
| Bofors RP3 | <<locked>> | 84% | 58,189 psi | 90% | 2680 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 44,512 psi | 68% | 2631 fps | 96.9% |
| Bofors RP5 | <<locked>> | 98% | 55,274 psi | 85% | 2776 fps | 99.3% |
| Bofors RP7 | <<locked>> | 88% | 57,217 psi | 88% | 2680 fps | 99.7% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 48,109 psi | 74% | 2648 fps | 97.8% |
| Hodgdon H380 | <<locked>> | 84% | 58,508 psi | 90% | 2703 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 55,724 psi | 86% | 2726 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 86% | 55,259 psi | 85% | 2687 fps | 99.3% |
| Hodgdon H4831 | <<locked>> | 96% | 56,130 psi | 86% | 2723 fps | 97.9% |
| Hodgdon H4831 SC | <<locked>> | 98% | 58,668 psi | 90% | 2762 fps | 98.3% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 58,566 psi | 90% | 2697 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 47,529 psi | 73% | 2746 fps | 99% |
| Hodgdon Superformance | <<locked>> | 88% | 56,043 psi | 86% | 2766 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,840 psi | 57% | 1647 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 55,535 psi | 85% | 2625 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 57,740 psi | 89% | 2661 fps | 99.9% |
| IMR 4350 | <<locked>> | 92% | 58,494 psi | 90% | 2713 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 88% | 58,610 psi | 90% | 2700 fps | 99.9% |
| IMR 4831 | <<locked>> | 92% | 57,870 psi | 89% | 2717 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 57,537 psi | 89% | 2710 fps | 98.2% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 57,072 psi | 88% | 2808 fps | 98.7% |
| Lovex S062 | <<locked>> | 82% | 55,869 psi | 86% | 2618 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 55,564 psi | 85% | 2648 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 57,087 psi | 88% | 2694 fps | 99.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 49,574 psi | 76% | 2605 fps | 99.8% |
| Norma 203B | <<locked>> | 82% | 56,724 psi | 87% | 2674 fps | 100% |
| Norma 204 | <<locked>> | 90% | 55,564 psi | 85% | 2713 fps | 99.1% |
| Norma MRP | <<locked>> | 96% | 55,056 psi | 85% | 2799 fps | 99.9% |
| Norma URP | <<locked>> | 90% | 56,159 psi | 86% | 2710 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 57,580 psi | 89% | 2700 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 58,088 psi | 89% | 2835 fps | 99.1% |
| Ramshot Hunter | <<locked>> | 92% | 58,639 psi | 90% | 2769 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 51,822 psi | 80% | 2710 fps | 99.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,623 psi | 58% | 1686 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 58,131 psi | 89% | 2690 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 55,259 psi | 85% | 2733 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 57,682 psi | 89% | 2753 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 55,753 psi | 86% | 2779 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 47,718 psi | 73% | 2746 fps | 99.6% |
| Rottweil R 902 | <<locked>> | 82% | 57,812 psi | 89% | 2628 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 58,320 psi | 90% | 2677 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 56,275 psi | 87% | 2697 fps | 98.5% |
| Rottweil R 905 | <<locked>> | 96% | 57,000 psi | 88% | 2753 fps | 99.5% |
| Rottweil R 907 | <<locked>> | 88% | 57,217 psi | 88% | 2680 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 88% | 55,564 psi | 85% | 2648 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 55,869 psi | 86% | 2618 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 57,087 psi | 88% | 2694 fps | 99.9% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 56,159 psi | 86% | 2687 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 58,523 psi | 90% | 2556 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 58,740 psi | 90% | 2654 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 56,521 psi | 87% | 2749 fps | 99.4% |
| Somchem S355 | <<locked>> | 86% | 57,957 psi | 89% | 2671 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 58,015 psi | 89% | 2694 fps | 98.1% |
| Somchem S365 | <<locked>> | 92% | 56,014 psi | 86% | 2713 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 57,696 psi | 89% | 2730 fps | 99.8% |
| Vihtavuori N135 | <<locked>> | 82% | 58,479 psi | 90% | 2582 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 58,320 psi | 90% | 2598 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 55,753 psi | 86% | 2602 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 58,233 psi | 90% | 2703 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 57,087 psi | 88% | 2710 fps | 99.6% |
| Vihtavuori N540 | <<locked>> | 82% | 56,405 psi | 87% | 2598 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 57,072 psi | 88% | 2707 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 58,668 psi | 90% | 2772 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 55,172 psi | 85% | 2792 fps | 98.1% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 50,676 psi | 78% | 2710 fps | 97.5% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 57,725 psi | 89% | 2667 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 56,028 psi | 86% | 2730 fps | 99.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 52,533 psi | 81% | 2825 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 57,711 psi | 89% | 2726 fps | 99.4% |
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 2700 | <<locked>> | 80% | 52,924 psi | 81% | 2582 fps | 99.3% |
| Accurate 3100 | <<locked>> | 80% | 30,530 psi | 47% | 2231 fps | 95.6% |
| Accurate 4064 | <<locked>> | 80% | 53,127 psi | 82% | 2566 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 41,278 psi | 64% | 2474 fps | 99.7% |
| Accurate MAGPRO | 58.9 gr | 92% | 47,036 psi | 72% | 2661 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 80% | 49,516 psi | 76% | 2546 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 37,014 psi | 57% | 2402 fps | 95% |
| ADI AR 2213 | <<locked>> | 90% | 42,989 psi | 66% | 2552 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 96% | 34,084 psi | 52% | 2408 fps | 95.8% |
| Alliant Power Pro Varmint | <<locked>> | 82% | 37,304 psi | 57% | 2405 fps | 95.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 50,575 psi | 78% | 2572 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 53,940 psi | 83% | 2638 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 39,697 psi | 61% | 2477 fps | 99.7% |
| Alliant Reloder-17 | <<locked>> | 80% | 45,295 psi | 70% | 2589 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 36,956 psi | 57% | 2402 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 86% | 37,115 psi | 57% | 2448 fps | 95.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,327 psi | 45% | 2260 fps | 98.7% |
| Alliant Reloder-25 | <<locked>> | 84% | 29,240 psi | 45% | 2274 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 31,531 psi | 49% | 2375 fps | 97.5% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 54,824 psi | 84% | 2690 fps | 95.3% |
| Bofors RP15 | <<locked>> | 88% | 36,840 psi | 57% | 2438 fps | 95.1% |
| Bofors RP3 | <<locked>> | 80% | 51,169 psi | 79% | 2585 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 39,001 psi | 60% | 2520 fps | 95.1% |
| Bofors RP5 | <<locked>> | 86% | 37,115 psi | 57% | 2448 fps | 95.4% |
| Bofors RP7 | <<locked>> | 80% | 44,686 psi | 69% | 2477 fps | 98.3% |
| Hodgdon H1000 | <<locked>> | 94% | 39,218 psi | 60% | 2474 fps | 95.1% |
| Hodgdon H380 | <<locked>> | 80% | 51,227 psi | 79% | 2598 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 42,902 psi | 66% | 2513 fps | 98.4% |
| Hodgdon H4350 | <<locked>> | 80% | 45,759 psi | 70% | 2533 fps | 97.9% |
| Hodgdon H4831 | <<locked>> | 90% | 45,788 psi | 70% | 2559 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 90% | 45,078 psi | 69% | 2543 fps | 95.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 37,376 psi | 58% | 2375 fps | 99.9% |
| Hodgdon Retumbo | <<locked>> | 92% | 36,811 psi | 57% | 2510 fps | 95.7% |
| Hodgdon Superformance | <<locked>> | 80% | 41,887 psi | 64% | 2533 fps | 98% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,485 psi | 42% | 1467 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 52,112 psi | 80% | 2575 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 54,273 psi | 83% | 2612 fps | 99.7% |
| IMR 4350 | <<locked>> | 80% | 40,205 psi | 62% | 2411 fps | 97.3% |
| IMR 4451 Enduron | <<locked>> | 80% | 46,035 psi | 71% | 2503 fps | 98.8% |
| IMR 4831 | <<locked>> | 80% | 39,305 psi | 60% | 2421 fps | 99.5% |
| IMR 4955 Enduron | <<locked>> | 88% | 44,846 psi | 69% | 2503 fps | 95.6% |
| IMR 7828 SSC | <<locked>> | 90% | 41,075 psi | 63% | 2530 fps | 95% |
| Lovex S062 | <<locked>> | 80% | 52,446 psi | 81% | 2572 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 43,569 psi | 67% | 2457 fps | 99.3% |
| Lovex S070 | <<locked>> | 80% | 41,756 psi | 64% | 2444 fps | 98.3% |
| Lovex S071 | <<locked>> | 84% | 29,849 psi | 46% | 2215 fps | 95.3% |
| Norma 203B | <<locked>> | 80% | 53,301 psi | 82% | 2625 fps | 100% |
| Norma 204 | <<locked>> | 80% | 39,697 psi | 61% | 2438 fps | 95.8% |
| Norma MRP | 51.5 gr | 82% | 33,895 psi | 52% | 2398 fps | 95.7% |
| Norma URP | <<locked>> | 80% | 40,596 psi | 62% | 2461 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 80% | 53,795 psi | 83% | 2648 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 40,814 psi | 63% | 2536 fps | 95.3% |
| Ramshot Hunter | <<locked>> | 80% | 39,378 psi | 61% | 2454 fps | 98.3% |
| Ramshot Magnum | <<locked>> | 90% | 36,216 psi | 56% | 2421 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,036 psi | 43% | 1503 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 51,126 psi | 79% | 2589 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 48,066 psi | 74% | 2631 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 41,002 psi | 63% | 2490 fps | 99.5% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 39,421 psi | 61% | 2500 fps | 99.3% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 33,620 psi | 52% | 2428 fps | 95.4% |
| Rottweil R 902 | <<locked>> | 80% | 54,273 psi | 83% | 2579 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 48,095 psi | 74% | 2536 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 40,901 psi | 63% | 2434 fps | 95.1% |
| Rottweil R 905 | <<locked>> | 82% | 36,071 psi | 55% | 2382 fps | 95% |
| Rottweil R 907 | <<locked>> | 80% | 44,686 psi | 69% | 2477 fps | 98.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 43,569 psi | 67% | 2457 fps | 99.3% |
| Shooters World Precision | <<locked>> | 80% | 52,446 psi | 81% | 2572 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 41,756 psi | 64% | 2444 fps | 98.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 49,226 psi | 76% | 2589 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 48,791 psi | 75% | 2431 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 42,685 psi | 66% | 2408 fps | 98.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 38,218 psi | 59% | 2434 fps | 95.8% |
| Somchem S355 | <<locked>> | 80% | 48,211 psi | 74% | 2533 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 44,440 psi | 68% | 2480 fps | 95.3% |
| Somchem S365 | <<locked>> | 80% | 37,333 psi | 57% | 2425 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 34,389 psi | 53% | 2320 fps | 95.3% |
| Vihtavuori N135 | <<locked>> | 80% | 54,824 psi | 84% | 2536 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 54,810 psi | 84% | 2552 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 46,021 psi | 71% | 2464 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 42,192 psi | 65% | 2461 fps | 99.7% |
| Vihtavuori N165 | <<locked>> | 86% | 36,172 psi | 56% | 2356 fps | 95.6% |
| Vihtavuori N540 | <<locked>> | 80% | 53,055 psi | 82% | 2552 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,466 psi | 64% | 2461 fps | 99.5% |
| Vihtavuori N555 | <<locked>> | 80% | 32,706 psi | 50% | 2329 fps | 98.6% |
| Vihtavuori N560 | 56.5 gr | 90% | 44,904 psi | 69% | 2618 fps | 95.8% |
| Vihtavuori N565 | <<locked>> | 94% | 41,394 psi | 64% | 2543 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 40,930 psi | 63% | 2428 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 43,149 psi | 66% | 2520 fps | 98.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 25,904 psi | 40% | 2254 fps | 98.3% |
| Winchester Supreme 780 | <<locked>> | 86% | 38,203 psi | 59% | 2402 fps | 95.6% |
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 90 powders for .280 Ackley Improved loaded with the .284 | 174gr | Prvi Partizan SP. Alliant Reloder-26 delivers the highest muzzle velocity at 2,838 fps; across all powders the maximum-charge window runs from 1,647 fps to 2,838 fps. ADI AR 2225 gives the best case fill at 100 %, and 90 of the 90 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 174.0 gr projectile in 0.284" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. ADI AR 2225, Alliant Reloder-23, Alliant Reloder-25 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. Vihtavuori N560, Norma MRP, Accurate MAGPRO rank at the top here: for .280 Ackley Improved with the .284 | 174gr | Prvi Partizan SP 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.