Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 183gr | Sierra MatchKing bullet and 93 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 2495 | <<locked>> | 82% | 57,943 psi | 89% | 2490 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 55,143 psi | 85% | 2526 fps | 99.5% |
| Accurate 3100ᴾ | <<locked>> | 100% | 57,319 psi | 88% | 2628 fps | 100% |
| Accurate 4064 | <<locked>> | 84% | 58,407 psi | 90% | 2546 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 55,753 psi | 86% | 2615 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 55,463 psi | 85% | 2717 fps | 97.7% |
| ADI AR 2208 | <<locked>> | 86% | 57,928 psi | 89% | 2579 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 56,231 psi | 87% | 2661 fps | 99.3% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 57,725 psi | 89% | 2717 fps | 98.8% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 37,188 psi | 57% | 2415 fps | 97.4% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 57,914 psi | 89% | 2700 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 55,724 psi | 86% | 2559 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 55,724 psi | 86% | 2575 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 56,521 psi | 87% | 2667 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 57,899 psi | 89% | 2684 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 55,608 psi | 86% | 2651 fps | 99.3% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 56,913 psi | 88% | 2713 fps | 99.5% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 53,969 psi | 83% | 2638 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 46,775 psi | 72% | 2589 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 98% | 58,146 psi | 89% | 2776 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 52,243 psi | 80% | 2644 fps | 99% |
| Bofors RP3 | <<locked>> | 84% | 56,362 psi | 87% | 2572 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 42,656 psi | 66% | 2520 fps | 96.6% |
| Bofors RP5ᴾ | <<locked>> | 100% | 56,913 psi | 88% | 2713 fps | 99.5% |
| Bofors RP7 | <<locked>> | 88% | 55,796 psi | 86% | 2569 fps | 99.7% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 46,180 psi | 71% | 2533 fps | 97.4% |
| Hodgdon H380 | <<locked>> | 84% | 56,550 psi | 87% | 2592 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 57,725 psi | 89% | 2667 fps | 100% |
| Hodgdon H4350 | <<locked>> | 88% | 57,246 psi | 88% | 2628 fps | 99.5% |
| Hodgdon H4831 | <<locked>> | 98% | 57,827 psi | 89% | 2661 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 98% | 56,840 psi | 87% | 2648 fps | 98.1% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 56,724 psi | 87% | 2592 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 57,957 psi | 89% | 2615 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 45,745 psi | 70% | 2631 fps | 98.8% |
| Hodgdon Superformance | <<locked>> | 90% | 58,233 psi | 90% | 2710 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,796 psi | 57% | 1578 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 58,624 psi | 90% | 2582 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 57,392 psi | 88% | 2562 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 56,579 psi | 87% | 2556 fps | 99.9% |
| IMR 4350 | <<locked>> | 92% | 56,594 psi | 87% | 2602 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 88% | 57,290 psi | 88% | 2592 fps | 99.9% |
| IMR 4831 | <<locked>> | 92% | 56,115 psi | 86% | 2608 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 57,145 psi | 88% | 2598 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 55,535 psi | 85% | 2595 fps | 98% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 55,027 psi | 85% | 2694 fps | 98.5% |
| Lovex S062 | <<locked>> | 84% | 57,696 psi | 89% | 2552 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 57,450 psi | 88% | 2585 fps | 100% |
| Lovex S070 | <<locked>> | 92% | 58,740 psi | 90% | 2628 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 47,601 psi | 73% | 2497 fps | 99.7% |
| Norma 203B | <<locked>> | 84% | 58,508 psi | 90% | 2608 fps | 100% |
| Norma 204 | <<locked>> | 92% | 57,609 psi | 89% | 2657 fps | 99.3% |
| Norma MRP | <<locked>> | 98% | 56,420 psi | 87% | 2733 fps | 100% |
| Norma URP | <<locked>> | 92% | 57,696 psi | 89% | 2644 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 55,782 psi | 86% | 2592 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 55,550 psi | 85% | 2710 fps | 98.9% |
| Ramshot Hunter | <<locked>> | 92% | 56,652 psi | 87% | 2657 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 49,734 psi | 77% | 2598 fps | 99.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,362 psi | 57% | 1611 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 56,434 psi | 87% | 2579 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 57,276 psi | 88% | 2671 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 55,463 psi | 85% | 2638 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 57,740 psi | 89% | 2717 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 45,498 psi | 70% | 2625 fps | 99.4% |
| Rottweil R 902 | <<locked>> | 82% | 56,434 psi | 87% | 2523 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 56,536 psi | 87% | 2569 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 58,088 psi | 89% | 2635 fps | 98.8% |
| Rottweil R 905 | <<locked>> | 98% | 58,639 psi | 90% | 2690 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 88% | 55,796 psi | 86% | 2569 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 90% | 57,450 psi | 88% | 2585 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 57,696 psi | 89% | 2552 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 58,740 psi | 90% | 2628 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 58,044 psi | 89% | 2625 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 57,145 psi | 88% | 2451 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 57,087 psi | 88% | 2546 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 58,146 psi | 89% | 2684 fps | 99.6% |
| Somchem S355 | <<locked>> | 86% | 56,434 psi | 87% | 2566 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 56,159 psi | 86% | 2582 fps | 97.9% |
| Somchem S365 | <<locked>> | 94% | 57,435 psi | 88% | 2644 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 55,608 psi | 86% | 2618 fps | 99.7% |
| Vihtavuori N135 | <<locked>> | 82% | 56,840 psi | 87% | 2477 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 56,884 psi | 88% | 2493 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 57,609 psi | 89% | 2539 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 56,347 psi | 87% | 2595 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 54,984 psi | 85% | 2595 fps | 99.5% |
| Vihtavuori N540 | <<locked>> | 84% | 58,392 psi | 90% | 2536 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 55,463 psi | 85% | 2602 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 56,521 psi | 87% | 2661 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 56,579 psi | 87% | 2726 fps | 98.4% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 48,573 psi | 75% | 2595 fps | 97.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 55,666 psi | 86% | 2562 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 57,725 psi | 89% | 2667 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 49,356 psi | 76% | 2707 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 55,666 psi | 86% | 2612 fps | 99.2% |
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% | 54,360 psi | 84% | 2451 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 51,590 psi | 79% | 2474 fps | 99.2% |
| Accurate 3100 | <<locked>> | 80% | 29,312 psi | 45% | 2139 fps | 95.4% |
| Accurate 4064 | <<locked>> | 80% | 51,576 psi | 79% | 2461 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 39,769 psi | 61% | 2369 fps | 99.6% |
| Accurate MAGPRO | <<locked>> | 92% | 44,860 psi | 69% | 2543 fps | 95.3% |
| ADI AR 2208 | <<locked>> | 80% | 48,443 psi | 75% | 2448 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 38,334 psi | 59% | 2356 fps | 95.7% |
| ADI AR 2213 | <<locked>> | 90% | 41,394 psi | 64% | 2444 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 96% | 32,750 psi | 50% | 2306 fps | 95.3% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 53,940 psi | 83% | 2648 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 49,240 psi | 76% | 2467 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 52,359 psi | 81% | 2530 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 38,435 psi | 59% | 2375 fps | 99.7% |
| Alliant Reloder-17 | <<locked>> | 80% | 43,787 psi | 67% | 2487 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 37,985 psi | 58% | 2349 fps | 95.7% |
| Alliant Reloder-22 | <<locked>> | 86% | 35,897 psi | 55% | 2349 fps | 95.1% |
| Alliant Reloder-23 | <<locked>> | 80% | 28,326 psi | 44% | 2165 fps | 98.5% |
| Alliant Reloder-25 | <<locked>> | 84% | 28,282 psi | 44% | 2178 fps | 95.2% |
| Alliant Reloder-26 | 48.1 gr | 80% | 30,182 psi | 46% | 2270 fps | 97.2% |
| Bofors RP15 | <<locked>> | 90% | 37,753 psi | 58% | 2385 fps | 95.6% |
| Bofors RP3 | <<locked>> | 80% | 49,661 psi | 76% | 2480 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 39,958 psi | 61% | 2467 fps | 95.7% |
| Bofors RP5 | <<locked>> | 86% | 35,897 psi | 55% | 2349 fps | 95.1% |
| Bofors RP7 | <<locked>> | 80% | 43,526 psi | 67% | 2375 fps | 98.1% |
| Hodgdon H1000 | <<locked>> | 96% | 40,582 psi | 62% | 2425 fps | 95.7% |
| Hodgdon H380 | <<locked>> | 80% | 49,922 psi | 77% | 2497 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 41,655 psi | 64% | 2411 fps | 98.3% |
| Hodgdon H4350 | <<locked>> | 80% | 44,483 psi | 68% | 2428 fps | 97.8% |
| Hodgdon H4831 | <<locked>> | 90% | 44,425 psi | 68% | 2454 fps | 95.5% |
| Hodgdon H4831 SC | <<locked>> | 90% | 43,395 psi | 67% | 2434 fps | 95.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 36,027 psi | 55% | 2277 fps | 99.9% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 54,447 psi | 84% | 2572 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 35,491 psi | 55% | 2402 fps | 95.2% |
| Hodgdon Superformance | <<locked>> | 80% | 40,480 psi | 62% | 2428 fps | 97.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,485 psi | 42% | 1407 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 54,795 psi | 84% | 2533 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 50,981 psi | 78% | 2474 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 52,968 psi | 81% | 2507 fps | 99.7% |
| IMR 4350 | <<locked>> | 80% | 38,943 psi | 60% | 2313 fps | 97.1% |
| IMR 4451 Enduron | <<locked>> | 80% | 44,657 psi | 69% | 2398 fps | 98.7% |
| IMR 4831 | <<locked>> | 80% | 38,116 psi | 59% | 2323 fps | 99.4% |
| IMR 4895 | <<locked>> | 80% | 53,722 psi | 83% | 2552 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 43,511 psi | 67% | 2402 fps | 95.4% |
| IMR 7828 SSC | <<locked>> | 92% | 42,293 psi | 65% | 2474 fps | 95.6% |
| Lovex S062 | <<locked>> | 80% | 51,285 psi | 79% | 2470 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 42,351 psi | 65% | 2356 fps | 99.2% |
| Lovex S070 | <<locked>> | 80% | 40,640 psi | 63% | 2346 fps | 98.2% |
| Lovex S071 | <<locked>> | 84% | 28,805 psi | 44% | 2126 fps | 95.1% |
| Norma 203B | <<locked>> | 80% | 51,735 psi | 80% | 2520 fps | 100% |
| Norma 204 | <<locked>> | 80% | 38,392 psi | 59% | 2339 fps | 95.6% |
| Norma MRP | 47.9 gr | 82% | 32,677 psi | 50% | 2300 fps | 95.4% |
| Norma URP | <<locked>> | 80% | 39,378 psi | 61% | 2362 fps | 99.5% |
| Ramshot Big Game | <<locked>> | 80% | 52,156 psi | 80% | 2543 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 41,974 psi | 65% | 2484 fps | 95.9% |
| Ramshot Hunter | <<locked>> | 80% | 38,029 psi | 59% | 2352 fps | 98.2% |
| Ramshot Magnum | <<locked>> | 90% | 34,824 psi | 54% | 2320 fps | 95.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,065 psi | 43% | 1440 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 49,734 psi | 77% | 2484 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 46,499 psi | 72% | 2526 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 39,392 psi | 61% | 2385 fps | 99.4% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 38,058 psi | 59% | 2395 fps | 99.1% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 34,548 psi | 53% | 2382 fps | 96.1% |
| Rottweil R 902 | <<locked>> | 80% | 53,040 psi | 82% | 2477 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 46,746 psi | 72% | 2434 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 42,438 psi | 65% | 2388 fps | 95.8% |
| Rottweil R 905 | <<locked>> | 84% | 37,275 psi | 57% | 2336 fps | 95.7% |
| Rottweil R 907 | <<locked>> | 80% | 43,526 psi | 67% | 2375 fps | 98.1% |
| Shooters World Long Rifle | <<locked>> | 80% | 42,351 psi | 65% | 2356 fps | 99.2% |
| Shooters World Precision | <<locked>> | 80% | 51,285 psi | 79% | 2470 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 40,640 psi | 63% | 2346 fps | 98.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 47,703 psi | 73% | 2484 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 47,543 psi | 73% | 2333 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 41,481 psi | 64% | 2310 fps | 98.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 36,927 psi | 57% | 2333 fps | 95.6% |
| Somchem S355 | <<locked>> | 80% | 46,847 psi | 72% | 2431 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 43,163 psi | 66% | 2379 fps | 95% |
| Somchem S365 | <<locked>> | 80% | 35,824 psi | 55% | 2323 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 33,243 psi | 51% | 2224 fps | 95.1% |
| Vihtavuori N135 | <<locked>> | 80% | 53,301 psi | 82% | 2434 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 53,476 psi | 82% | 2451 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 44,788 psi | 69% | 2365 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 40,799 psi | 63% | 2359 fps | 99.6% |
| Vihtavuori N165 | <<locked>> | 86% | 34,751 psi | 53% | 2254 fps | 95.3% |
| Vihtavuori N540 | <<locked>> | 80% | 51,735 psi | 80% | 2454 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 40,248 psi | 62% | 2362 fps | 99.5% |
| Vihtavuori N555 | <<locked>> | 80% | 31,473 psi | 48% | 2234 fps | 98.5% |
| Vihtavuori N560 | 52.6 gr | 90% | 43,366 psi | 67% | 2510 fps | 95.5% |
| Vihtavuori N565 | <<locked>> | 96% | 42,438 psi | 65% | 2490 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 39,682 psi | 61% | 2329 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 41,655 psi | 64% | 2411 fps | 98.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,961 psi | 38% | 2156 fps | 98.1% |
| Winchester Supreme 780 | <<locked>> | 86% | 36,854 psi | 57% | 2303 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 99 powders for .280 Ackley Improved loaded with the .284 | 183gr | Sierra MatchKing. Alliant Reloder-26 delivers the highest muzzle velocity at 2,776 fps; across all powders the maximum-charge window runs from 1,578 fps to 2,776 fps. Accurate 3100 gives the best case fill at 100 %, and 99 of the 99 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 50–90 %, leaving at least 10 % headroom. The 183.0 gr projectile in 0.284" calls for a 1:8.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2213, ADI AR 2217 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 | 183gr | Sierra MatchKing they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, IMR 8133 Enduron, Norma 217, ReloadSwiss RS 80 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.