Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 175gr | Sierra GameKing bullet and 90 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.
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% | 56,188 psi | 86% | 2618 fps | 99.6% |
| Accurate 3100 | <<locked>> | 98% | 55,114 psi | 85% | 2674 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 55,956 psi | 86% | 2592 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 56,985 psi | 88% | 2707 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 57,421 psi | 88% | 2818 fps | 97.9% |
| ADI AR 2208 | <<locked>> | 84% | 55,622 psi | 86% | 2625 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 57,812 psi | 89% | 2759 fps | 99.4% |
| ADI AR 2213 | <<locked>> | 98% | 55,288 psi | 85% | 2759 fps | 98.4% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 38,189 psi | 59% | 2507 fps | 97.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 56,811 psi | 87% | 2651 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 56,840 psi | 87% | 2671 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 57,769 psi | 89% | 2759 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 55,492 psi | 85% | 2730 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 57,159 psi | 88% | 2749 fps | 99.4% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 58,421 psi | 90% | 2808 fps | 99.6% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 55,564 psi | 85% | 2730 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 48,153 psi | 74% | 2684 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 55,869 psi | 86% | 2822 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 57,769 psi | 89% | 2723 fps | 95.9% |
| Bofors RP15ᴾ | <<locked>> | 100% | 53,548 psi | 82% | 2736 fps | 99% |
| Bofors RP3 | <<locked>> | 84% | 57,653 psi | 89% | 2664 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 43,961 psi | 68% | 2612 fps | 96.8% |
| Bofors RP5ᴾ | <<locked>> | 100% | 58,421 psi | 90% | 2808 fps | 99.6% |
| Bofors RP7 | <<locked>> | 88% | 56,782 psi | 87% | 2661 fps | 99.7% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 47,645 psi | 73% | 2631 fps | 97.7% |
| Hodgdon H380 | <<locked>> | 84% | 58,015 psi | 89% | 2687 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 55,332 psi | 85% | 2710 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 88% | 58,436 psi | 90% | 2720 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 96% | 55,550 psi | 85% | 2707 fps | 97.8% |
| Hodgdon H4831 SC | <<locked>> | 98% | 58,088 psi | 89% | 2740 fps | 98.2% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 58,160 psi | 89% | 2684 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 47,079 psi | 72% | 2726 fps | 98.9% |
| Hodgdon Superformance | <<locked>> | 88% | 55,419 psi | 85% | 2746 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,753 psi | 57% | 1637 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 58,566 psi | 90% | 2654 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 57,551 psi | 89% | 2648 fps | 99.9% |
| IMR 4350 | <<locked>> | 92% | 57,798 psi | 89% | 2694 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 88% | 58,204 psi | 90% | 2684 fps | 99.9% |
| IMR 4831 | <<locked>> | 92% | 57,464 psi | 88% | 2700 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 58,334 psi | 90% | 2694 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 56,942 psi | 88% | 2690 fps | 98.1% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 56,507 psi | 87% | 2789 fps | 98.6% |
| Lovex S062 | <<locked>> | 82% | 55,579 psi | 86% | 2605 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 58,668 psi | 90% | 2680 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 56,695 psi | 87% | 2677 fps | 99.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 48,936 psi | 75% | 2585 fps | 99.7% |
| Norma 203B | <<locked>> | 82% | 56,188 psi | 86% | 2657 fps | 100% |
| Norma 204 | <<locked>> | 90% | 55,230 psi | 85% | 2700 fps | 99% |
| Norma MRP | <<locked>> | 98% | 58,320 psi | 90% | 2835 fps | 100% |
| Norma URP | <<locked>> | 90% | 55,753 psi | 86% | 2694 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 57,130 psi | 88% | 2684 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 57,174 psi | 88% | 2812 fps | 99% |
| Ramshot Hunter | <<locked>> | 92% | 57,957 psi | 89% | 2749 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 51,372 psi | 79% | 2694 fps | 99.3% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,536 psi | 58% | 1677 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 57,667 psi | 89% | 2674 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 54,766 psi | 84% | 2717 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 56,985 psi | 88% | 2733 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 55,143 psi | 85% | 2759 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 47,108 psi | 72% | 2723 fps | 99.6% |
| Rottweil R 902 | <<locked>> | 82% | 57,217 psi | 88% | 2608 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 57,841 psi | 89% | 2661 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 55,651 psi | 86% | 2677 fps | 98.4% |
| Rottweil R 905 | <<locked>> | 96% | 56,666 psi | 87% | 2736 fps | 99.4% |
| Rottweil R 907 | <<locked>> | 88% | 56,782 psi | 87% | 2661 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 90% | 58,668 psi | 90% | 2680 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 55,579 psi | 86% | 2605 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 56,695 psi | 87% | 2677 fps | 99.9% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 55,695 psi | 86% | 2671 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 58,291 psi | 90% | 2543 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 58,320 psi | 90% | 2641 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 56,202 psi | 86% | 2736 fps | 99.4% |
| Somchem S355 | <<locked>> | 86% | 57,725 psi | 89% | 2657 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 57,551 psi | 89% | 2677 fps | 98% |
| Somchem S365 | <<locked>> | 92% | 55,274 psi | 85% | 2694 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 57,087 psi | 88% | 2713 fps | 99.7% |
| Vihtavuori N135 | <<locked>> | 82% | 57,812 psi | 89% | 2566 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 58,059 psi | 89% | 2585 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 55,274 psi | 85% | 2585 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 57,508 psi | 88% | 2684 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 56,507 psi | 87% | 2690 fps | 99.6% |
| Vihtavuori N540 | <<locked>> | 82% | 55,927 psi | 86% | 2582 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 56,666 psi | 87% | 2694 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 57,943 psi | 89% | 2753 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 58,334 psi | 90% | 2828 fps | 98.5% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 50,198 psi | 77% | 2694 fps | 97.4% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 57,130 psi | 88% | 2654 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 55,608 psi | 86% | 2713 fps | 99.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 51,488 psi | 79% | 2805 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 57,188 psi | 88% | 2707 fps | 99.3% |
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% | 52,765 psi | 81% | 2569 fps | 99.3% |
| Accurate 3100 | <<locked>> | 80% | 30,110 psi | 46% | 2215 fps | 95.5% |
| Accurate 4064 | <<locked>> | 80% | 52,779 psi | 81% | 2552 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 40,741 psi | 63% | 2454 fps | 99.6% |
| Accurate MAGPRO | <<locked>> | 92% | 46,485 psi | 72% | 2641 fps | 95.6% |
| ADI AR 2208 | <<locked>> | 80% | 49,240 psi | 76% | 2533 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 39,131 psi | 60% | 2438 fps | 95.8% |
| ADI AR 2213 | <<locked>> | 90% | 42,453 psi | 65% | 2536 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 96% | 33,692 psi | 52% | 2392 fps | 95.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 50,024 psi | 77% | 2556 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 53,374 psi | 82% | 2621 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 39,407 psi | 61% | 2464 fps | 99.7% |
| Alliant Reloder-17 | <<locked>> | 80% | 44,802 psi | 69% | 2572 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 36,535 psi | 56% | 2382 fps | 95% |
| Alliant Reloder-22 | <<locked>> | 86% | 36,753 psi | 57% | 2431 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,109 psi | 45% | 2247 fps | 98.6% |
| Alliant Reloder-25 | <<locked>> | 84% | 28,921 psi | 44% | 2257 fps | 95.3% |
| Alliant Reloder-26 | 51.1 gr | 80% | 31,183 psi | 48% | 2359 fps | 97.4% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 54,230 psi | 83% | 2667 fps | 95.1% |
| Bofors RP15 | <<locked>> | 90% | 38,928 psi | 60% | 2477 fps | 95.8% |
| Bofors RP3 | <<locked>> | 80% | 50,633 psi | 78% | 2569 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 38,508 psi | 59% | 2503 fps | 95% |
| Bofors RP5 | <<locked>> | 86% | 36,753 psi | 57% | 2431 fps | 95.2% |
| Bofors RP7 | <<locked>> | 80% | 44,237 psi | 68% | 2461 fps | 98.2% |
| Hodgdon H1000 | <<locked>> | 94% | 39,001 psi | 60% | 2461 fps | 95% |
| Hodgdon H380 | <<locked>> | 80% | 50,749 psi | 78% | 2582 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 42,438 psi | 65% | 2497 fps | 98.3% |
| Hodgdon H4350 | <<locked>> | 80% | 45,295 psi | 70% | 2513 fps | 97.8% |
| Hodgdon H4831 | <<locked>> | 90% | 45,498 psi | 70% | 2543 fps | 95.6% |
| Hodgdon H4831 SC | <<locked>> | 90% | 44,483 psi | 68% | 2526 fps | 95.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 36,840 psi | 57% | 2356 fps | 99.9% |
| Hodgdon Retumbo | <<locked>> | 92% | 36,347 psi | 56% | 2490 fps | 95.5% |
| Hodgdon Superformance | <<locked>> | 80% | 41,495 psi | 64% | 2516 fps | 97.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,499 psi | 42% | 1460 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 51,822 psi | 80% | 2562 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 54,056 psi | 83% | 2598 fps | 99.7% |
| IMR 4350 | <<locked>> | 80% | 39,769 psi | 61% | 2395 fps | 97.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 45,571 psi | 70% | 2484 fps | 98.7% |
| IMR 4831 | <<locked>> | 80% | 39,030 psi | 60% | 2408 fps | 99.5% |
| IMR 4895 | <<locked>> | 80% | 54,752 psi | 84% | 2644 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 44,498 psi | 68% | 2490 fps | 95.5% |
| IMR 7828 SSC | <<locked>> | 92% | 43,511 psi | 67% | 2569 fps | 95.8% |
| Lovex S062 | <<locked>> | 80% | 52,156 psi | 80% | 2556 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 43,294 psi | 67% | 2444 fps | 99.3% |
| Lovex S070 | <<locked>> | 80% | 41,539 psi | 64% | 2428 fps | 98.3% |
| Lovex S071 | <<locked>> | 84% | 29,602 psi | 46% | 2201 fps | 95.2% |
| Norma 203B | <<locked>> | 80% | 52,707 psi | 81% | 2608 fps | 100% |
| Norma 204 | <<locked>> | 80% | 39,276 psi | 60% | 2425 fps | 95.7% |
| Norma MRP | 50.8 gr | 82% | 33,533 psi | 52% | 2382 fps | 95.5% |
| Norma URP | <<locked>> | 80% | 40,306 psi | 62% | 2444 fps | 99.5% |
| Ramshot Big Game | <<locked>> | 80% | 53,316 psi | 82% | 2631 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 40,263 psi | 62% | 2516 fps | 95.1% |
| Ramshot Hunter | <<locked>> | 80% | 38,957 psi | 60% | 2438 fps | 98.3% |
| Ramshot Magnum | <<locked>> | 90% | 35,752 psi | 55% | 2402 fps | 95.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,050 psi | 43% | 1496 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 50,633 psi | 78% | 2572 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 47,558 psi | 73% | 2615 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 40,567 psi | 62% | 2474 fps | 99.5% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 39,015 psi | 60% | 2484 fps | 99.2% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 33,243 psi | 51% | 2411 fps | 95.2% |
| Rottweil R 902 | <<locked>> | 80% | 53,969 psi | 83% | 2566 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 47,790 psi | 74% | 2523 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 40,683 psi | 63% | 2421 fps | 95% |
| Rottweil R 905 | <<locked>> | 84% | 38,145 psi | 59% | 2418 fps | 95.8% |
| Rottweil R 907 | <<locked>> | 80% | 44,237 psi | 68% | 2461 fps | 98.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 43,294 psi | 67% | 2444 fps | 99.3% |
| Shooters World Precision | <<locked>> | 80% | 52,156 psi | 80% | 2556 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 41,539 psi | 64% | 2428 fps | 98.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 48,747 psi | 75% | 2569 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 48,501 psi | 75% | 2418 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 42,264 psi | 65% | 2392 fps | 98.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 37,782 psi | 58% | 2415 fps | 95.6% |
| Somchem S355 | <<locked>> | 80% | 47,935 psi | 74% | 2520 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 44,135 psi | 68% | 2464 fps | 95.1% |
| Somchem S365 | <<locked>> | 80% | 36,811 psi | 57% | 2405 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 33,982 psi | 52% | 2300 fps | 95.2% |
| Vihtavuori N135 | <<locked>> | 80% | 54,418 psi | 84% | 2523 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 54,505 psi | 84% | 2539 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 45,759 psi | 70% | 2451 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 41,669 psi | 64% | 2441 fps | 99.7% |
| Vihtavuori N165 | <<locked>> | 86% | 35,795 psi | 55% | 2339 fps | 95.5% |
| Vihtavuori N540 | <<locked>> | 80% | 52,547 psi | 81% | 2536 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,002 psi | 63% | 2444 fps | 99.5% |
| Vihtavuori N555 | <<locked>> | 80% | 32,416 psi | 50% | 2316 fps | 98.6% |
| Vihtavuori N560 | 55.8 gr | 90% | 44,556 psi | 69% | 2602 fps | 95.7% |
| Vihtavuori N565 | <<locked>> | 96% | 43,642 psi | 67% | 2579 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 40,553 psi | 62% | 2411 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 42,670 psi | 66% | 2500 fps | 98.4% |
| Winchester StaBALL HD | <<locked>> | 80% | 25,614 psi | 39% | 2234 fps | 98.2% |
| Winchester Supreme 780 | <<locked>> | 86% | 37,840 psi | 58% | 2385 fps | 95.4% |
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 | 175gr | Sierra GameKing. Norma MRP delivers the highest muzzle velocity at 2,835 fps; across all powders the maximum-charge window runs from 1,637 fps to 2,835 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 175.0 gr projectile in 0.284" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. ADI AR 2225, Alliant Reloder-22, 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. Alliant Reloder-26, Norma MRP, Vihtavuori N560 rank at the top here: for .280 Ackley Improved with the .284 | 175gr | Sierra GameKing 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.