Load Specifications
Load data in caliber .280 Ackley Improved with .285 | 173gr | Prvi Partizan FMJ BT bullet and 91 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Norma MRP, Vihtavuori N560 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.
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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 2700 | <<locked>> | 82% | 56,811 psi | 87% | 2648 fps | 99.6% |
| Accurate 3100 | <<locked>> | 98% | 55,767 psi | 86% | 2700 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 56,579 psi | 87% | 2621 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 57,957 psi | 89% | 2740 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 58,247 psi | 90% | 2851 fps | 98% |
| ADI AR 2208 | <<locked>> | 84% | 56,101 psi | 86% | 2651 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 58,537 psi | 90% | 2792 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 98% | 56,217 psi | 86% | 2792 fps | 98.5% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 43,859 psi | 67% | 2572 fps | 95.9% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 38,812 psi | 60% | 2536 fps | 97.8% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 58,639 psi | 90% | 2785 fps | 99.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 57,290 psi | 88% | 2677 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 57,348 psi | 88% | 2697 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 58,450 psi | 90% | 2789 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 56,144 psi | 86% | 2759 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 57,870 psi | 89% | 2779 fps | 99.4% |
| Alliant Reloder-22 | <<locked>> | 98% | 55,651 psi | 86% | 2789 fps | 99.3% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 56,289 psi | 87% | 2759 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 48,733 psi | 75% | 2713 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 56,855 psi | 87% | 2851 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 58,349 psi | 90% | 2753 fps | 96.1% |
| Bofors RP15ᴾ | <<locked>> | 100% | 54,520 psi | 84% | 2769 fps | 99.1% |
| Bofors RP3 | <<locked>> | 84% | 58,378 psi | 90% | 2694 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 44,585 psi | 69% | 2641 fps | 96.9% |
| Bofors RP5 | <<locked>> | 98% | 55,651 psi | 86% | 2789 fps | 99.3% |
| Bofors RP7 | <<locked>> | 88% | 57,406 psi | 88% | 2690 fps | 99.7% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 48,095 psi | 74% | 2657 fps | 97.8% |
| Hodgdon H380 | <<locked>> | 84% | 58,392 psi | 90% | 2713 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 56,173 psi | 86% | 2743 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 86% | 55,448 psi | 85% | 2700 fps | 99.3% |
| Hodgdon H4831 | <<locked>> | 96% | 56,217 psi | 86% | 2733 fps | 97.9% |
| Hodgdon H4831 SC | <<locked>> | 96% | 54,969 psi | 85% | 2717 fps | 97.7% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 58,784 psi | 90% | 2710 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 47,834 psi | 74% | 2762 fps | 99% |
| Hodgdon Superformance | <<locked>> | 88% | 56,420 psi | 87% | 2779 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,724 psi | 56% | 1654 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 55,767 psi | 86% | 2638 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 57,957 psi | 89% | 2674 fps | 99.9% |
| IMR 4350 | <<locked>> | 92% | 58,610 psi | 90% | 2726 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 88% | 58,784 psi | 90% | 2710 fps | 99.9% |
| IMR 4831 | <<locked>> | 92% | 58,044 psi | 89% | 2730 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 57,580 psi | 89% | 2720 fps | 98.2% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 57,464 psi | 88% | 2825 fps | 98.8% |
| Lovex S062 | <<locked>> | 82% | 56,101 psi | 86% | 2631 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 55,753 psi | 86% | 2661 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 57,246 psi | 88% | 2707 fps | 99.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 49,676 psi | 76% | 2615 fps | 99.8% |
| Norma 203B | <<locked>> | 82% | 56,666 psi | 87% | 2680 fps | 100% |
| Norma 204 | <<locked>> | 90% | 55,956 psi | 86% | 2730 fps | 99.1% |
| Norma MRP | <<locked>> | 96% | 55,158 psi | 85% | 2808 fps | 99.9% |
| Norma URP | <<locked>> | 90% | 56,333 psi | 87% | 2723 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 57,769 psi | 89% | 2713 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 58,102 psi | 89% | 2844 fps | 99.1% |
| Ramshot Hunter | <<locked>> | 92% | 58,711 psi | 90% | 2779 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 52,098 psi | 80% | 2723 fps | 99.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,492 psi | 58% | 1693 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 58,305 psi | 90% | 2700 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 55,477 psi | 85% | 2746 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 57,783 psi | 89% | 2762 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 55,883 psi | 86% | 2789 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 47,659 psi | 73% | 2753 fps | 99.6% |
| Rottweil R 902 | <<locked>> | 82% | 57,783 psi | 89% | 2635 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 58,566 psi | 90% | 2690 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 56,434 psi | 87% | 2710 fps | 98.5% |
| Rottweil R 905 | <<locked>> | 96% | 57,421 psi | 88% | 2769 fps | 99.5% |
| Rottweil R 907 | <<locked>> | 88% | 57,406 psi | 88% | 2690 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 88% | 55,753 psi | 86% | 2661 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 56,101 psi | 86% | 2631 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 57,246 psi | 88% | 2707 fps | 99.9% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 56,333 psi | 87% | 2700 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 58,769 psi | 90% | 2566 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 55,230 psi | 85% | 2618 fps | 99.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 56,942 psi | 88% | 2762 fps | 99.4% |
| Somchem S355 | <<locked>> | 86% | 58,146 psi | 89% | 2684 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 58,015 psi | 89% | 2703 fps | 98.1% |
| Somchem S365 | <<locked>> | 92% | 56,159 psi | 86% | 2723 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 57,754 psi | 89% | 2740 fps | 99.8% |
| Vihtavuori N135 | <<locked>> | 82% | 58,450 psi | 90% | 2592 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 58,581 psi | 90% | 2608 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 55,956 psi | 86% | 2612 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 58,378 psi | 90% | 2717 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 57,101 psi | 88% | 2720 fps | 99.6% |
| Vihtavuori N540 | <<locked>> | 82% | 56,579 psi | 87% | 2608 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 57,464 psi | 88% | 2723 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 55,361 psi | 85% | 2740 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 55,187 psi | 85% | 2802 fps | 98.1% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 50,952 psi | 78% | 2723 fps | 97.5% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 57,798 psi | 89% | 2680 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 56,173 psi | 86% | 2743 fps | 99.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 52,634 psi | 81% | 2835 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 58,102 psi | 89% | 2740 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% | 53,156 psi | 82% | 2595 fps | 99.3% |
| Accurate 3100 | <<locked>> | 80% | 30,530 psi | 47% | 2241 fps | 95.6% |
| Accurate 4064 | <<locked>> | 80% | 53,417 psi | 82% | 2579 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 41,249 psi | 63% | 2480 fps | 99.7% |
| Accurate MAGPRO | 59.3 gr | 92% | 47,094 psi | 72% | 2671 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 80% | 49,748 psi | 77% | 2559 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 37,188 psi | 57% | 2415 fps | 95% |
| ADI AR 2213 | <<locked>> | 90% | 43,091 psi | 66% | 2566 fps | 95.5% |
| ADI AR 2217 | <<locked>> | 98% | 41,089 psi | 63% | 2516 fps | 95% |
| ADI AR 2225 | <<locked>> | 96% | 34,127 psi | 53% | 2418 fps | 95.8% |
| Alliant Power Pro Varmint | <<locked>> | 82% | 37,275 psi | 57% | 2411 fps | 95.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 50,575 psi | 78% | 2582 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 53,896 psi | 83% | 2648 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 39,711 psi | 61% | 2487 fps | 99.7% |
| Alliant Reloder-17 | <<locked>> | 80% | 45,484 psi | 70% | 2602 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 36,941 psi | 57% | 2408 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 86% | 37,260 psi | 57% | 2457 fps | 95.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,501 psi | 45% | 2270 fps | 98.7% |
| Alliant Reloder-25 | <<locked>> | 84% | 29,370 psi | 45% | 2280 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 31,517 psi | 48% | 2382 fps | 97.5% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 55,085 psi | 85% | 2703 fps | 95.3% |
| Bofors RP15 | <<locked>> | 88% | 36,985 psi | 57% | 2451 fps | 95.1% |
| Bofors RP3 | <<locked>> | 80% | 51,111 psi | 79% | 2595 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 39,073 psi | 60% | 2530 fps | 95.1% |
| Bofors RP5 | <<locked>> | 86% | 37,260 psi | 57% | 2457 fps | 95.4% |
| Bofors RP7 | <<locked>> | 80% | 44,686 psi | 69% | 2487 fps | 98.3% |
| Hodgdon H1000 | <<locked>> | 94% | 39,523 psi | 61% | 2487 fps | 95.2% |
| Hodgdon H380 | <<locked>> | 80% | 51,474 psi | 79% | 2615 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 43,105 psi | 66% | 2526 fps | 98.4% |
| Hodgdon H4350 | <<locked>> | 80% | 45,730 psi | 70% | 2539 fps | 97.9% |
| Hodgdon H4831 | <<locked>> | 90% | 45,948 psi | 71% | 2569 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 90% | 45,194 psi | 70% | 2556 fps | 95.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 37,376 psi | 58% | 2382 fps | 99.9% |
| Hodgdon Retumbo | <<locked>> | 92% | 36,912 psi | 57% | 2520 fps | 95.7% |
| Hodgdon Superformance | <<locked>> | 80% | 42,032 psi | 65% | 2543 fps | 98% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,456 psi | 42% | 1473 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 52,359 psi | 81% | 2589 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 54,520 psi | 84% | 2625 fps | 99.7% |
| IMR 4350 | <<locked>> | 80% | 40,190 psi | 62% | 2421 fps | 97.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 46,021 psi | 71% | 2510 fps | 98.8% |
| IMR 4831 | <<locked>> | 80% | 39,508 psi | 61% | 2434 fps | 99.5% |
| IMR 4955 Enduron | <<locked>> | 88% | 44,991 psi | 69% | 2516 fps | 95.7% |
| IMR 7828 SSC | <<locked>> | 90% | 41,191 psi | 63% | 2539 fps | 95% |
| Lovex S062 | <<locked>> | 80% | 52,692 psi | 81% | 2582 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 43,772 psi | 67% | 2470 fps | 99.3% |
| Lovex S070 | <<locked>> | 80% | 41,989 psi | 65% | 2454 fps | 98.3% |
| Lovex S071 | <<locked>> | 84% | 30,008 psi | 46% | 2228 fps | 95.4% |
| Norma 203B | <<locked>> | 80% | 53,229 psi | 82% | 2635 fps | 100% |
| Norma 204 | <<locked>> | 80% | 39,885 psi | 61% | 2451 fps | 95.9% |
| Norma MRP | 51.9 gr | 82% | 34,069 psi | 52% | 2411 fps | 95.7% |
| Norma URP | <<locked>> | 80% | 40,799 psi | 63% | 2474 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 80% | 54,012 psi | 83% | 2661 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 40,886 psi | 63% | 2546 fps | 95.3% |
| Ramshot Hunter | <<locked>> | 80% | 39,581 psi | 61% | 2464 fps | 98.4% |
| Ramshot Magnum | <<locked>> | 90% | 36,289 psi | 56% | 2431 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,195 psi | 43% | 1512 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 51,300 psi | 79% | 2602 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 48,283 psi | 74% | 2644 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 40,988 psi | 63% | 2497 fps | 99.5% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 39,552 psi | 61% | 2513 fps | 99.3% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 33,707 psi | 52% | 2438 fps | 95.4% |
| Rottweil R 902 | <<locked>> | 80% | 54,549 psi | 84% | 2592 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 48,341 psi | 74% | 2549 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 41,060 psi | 63% | 2448 fps | 95.1% |
| Rottweil R 905 | <<locked>> | 82% | 36,085 psi | 56% | 2392 fps | 95% |
| Rottweil R 907 | <<locked>> | 80% | 44,686 psi | 69% | 2487 fps | 98.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 43,772 psi | 67% | 2470 fps | 99.3% |
| Shooters World Precision | <<locked>> | 80% | 52,692 psi | 81% | 2582 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 41,989 psi | 65% | 2454 fps | 98.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 49,472 psi | 76% | 2602 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 49,066 psi | 75% | 2444 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 42,670 psi | 66% | 2418 fps | 98.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 38,189 psi | 59% | 2441 fps | 95.7% |
| Somchem S355 | <<locked>> | 80% | 48,443 psi | 75% | 2546 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 44,541 psi | 69% | 2490 fps | 95.3% |
| Somchem S365 | <<locked>> | 80% | 37,333 psi | 57% | 2431 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 34,360 psi | 53% | 2326 fps | 95.3% |
| Vihtavuori N135 | <<locked>> | 80% | 55,129 psi | 85% | 2549 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 55,042 psi | 85% | 2566 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 46,267 psi | 71% | 2477 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 42,177 psi | 65% | 2467 fps | 99.7% |
| Vihtavuori N165 | <<locked>> | 86% | 36,129 psi | 56% | 2362 fps | 95.5% |
| Vihtavuori N540 | <<locked>> | 80% | 53,258 psi | 82% | 2566 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,655 psi | 64% | 2474 fps | 99.6% |
| Vihtavuori N555 | <<locked>> | 80% | 32,909 psi | 51% | 2343 fps | 98.6% |
| Vihtavuori N560 | 56.9 gr | 90% | 44,991 psi | 69% | 2628 fps | 95.8% |
| Vihtavuori N565 | <<locked>> | 94% | 41,466 psi | 64% | 2549 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 41,104 psi | 63% | 2438 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 43,105 psi | 66% | 2526 fps | 98.4% |
| Winchester StaBALL HD | <<locked>> | 80% | 26,049 psi | 40% | 2264 fps | 98.4% |
| Winchester Supreme 780 | <<locked>> | 86% | 38,348 psi | 59% | 2411 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 91 powders for .280 Ackley Improved loaded with the .285 | 173gr | Prvi Partizan FMJ BT. Accurate MAGPRO delivers the highest muzzle velocity at 2,851 fps; across all powders the maximum-charge window runs from 1,654 fps to 2,851 fps. ADI AR 2217 gives the best case fill at 100 %, and 91 of the 91 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 173.0 gr projectile in 0.285" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Alliant Reloder-23 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. Norma MRP, Vihtavuori N560, Accurate MAGPRO rank at the top here: for .280 Ackley Improved with the .285 | 173gr | Prvi Partizan FMJ BT 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.