Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 175gr | Speer Grand Slam bullet and 92 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.
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% | 57,043 psi | 88% | 2635 fps | 99.7% |
| Accurate 3100 | <<locked>> | 98% | 56,231 psi | 87% | 2694 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 57,087 psi | 88% | 2608 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 58,320 psi | 90% | 2730 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 58,436 psi | 90% | 2838 fps | 98.1% |
| ADI AR 2208 | <<locked>> | 84% | 56,550 psi | 87% | 2644 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 55,216 psi | 85% | 2726 fps | 99.2% |
| ADI AR 2213 | <<locked>> | 98% | 56,304 psi | 87% | 2779 fps | 98.6% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 44,179 psi | 68% | 2569 fps | 96.2% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 38,914 psi | 60% | 2526 fps | 97.9% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 55,361 psi | 85% | 2723 fps | 99.2% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 55,361 psi | 85% | 2723 fps | 99.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 57,537 psi | 89% | 2661 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 57,595 psi | 89% | 2684 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 58,798 psi | 90% | 2776 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 56,507 psi | 87% | 2746 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 58,233 psi | 90% | 2766 fps | 99.5% |
| Alliant Reloder-22 | <<locked>> | 98% | 55,796 psi | 86% | 2776 fps | 99.4% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 56,753 psi | 87% | 2749 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 49,110 psi | 76% | 2703 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 57,058 psi | 88% | 2838 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 58,697 psi | 90% | 2743 fps | 96.3% |
| Bofors RP15ᴾ | <<locked>> | 100% | 54,897 psi | 84% | 2762 fps | 99.2% |
| Bofors RP3 | <<locked>> | 84% | 58,653 psi | 90% | 2680 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 44,947 psi | 69% | 2631 fps | 97.1% |
| Bofors RP5 | <<locked>> | 98% | 55,796 psi | 86% | 2776 fps | 99.4% |
| Bofors RP7 | <<locked>> | 88% | 57,667 psi | 89% | 2677 fps | 99.8% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 48,457 psi | 75% | 2651 fps | 98% |
| Hodgdon H380 | <<locked>> | 84% | 58,668 psi | 90% | 2700 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 56,202 psi | 86% | 2726 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 86% | 55,709 psi | 86% | 2687 fps | 99.4% |
| Hodgdon H4831 | <<locked>> | 96% | 56,550 psi | 87% | 2726 fps | 98.1% |
| Hodgdon H4831 SC | <<locked>> | 96% | 55,361 psi | 85% | 2707 fps | 97.9% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 55,680 psi | 86% | 2657 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 47,935 psi | 74% | 2749 fps | 99.1% |
| Hodgdon Superformance | <<locked>> | 88% | 56,507 psi | 87% | 2766 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,941 psi | 57% | 1644 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 55,970 psi | 86% | 2625 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 58,160 psi | 89% | 2661 fps | 99.9% |
| IMR 4350 | <<locked>> | 90% | 55,405 psi | 85% | 2664 fps | 99.7% |
| IMR 4451 Enduron | <<locked>> | 86% | 55,535 psi | 85% | 2651 fps | 99.8% |
| IMR 4831 | <<locked>> | 92% | 58,392 psi | 90% | 2717 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 57,928 psi | 89% | 2710 fps | 98.4% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 57,856 psi | 89% | 2815 fps | 98.9% |
| Lovex S062 | <<locked>> | 82% | 56,304 psi | 87% | 2618 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 55,999 psi | 86% | 2648 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 57,537 psi | 89% | 2694 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 50,024 psi | 77% | 2605 fps | 99.8% |
| Norma 203B | <<locked>> | 82% | 56,884 psi | 88% | 2667 fps | 100% |
| Norma 204 | <<locked>> | 90% | 56,028 psi | 86% | 2713 fps | 99.2% |
| Norma MRP | <<locked>> | 96% | 55,579 psi | 86% | 2799 fps | 99.9% |
| Norma URP | <<locked>> | 90% | 56,637 psi | 87% | 2710 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 58,059 psi | 89% | 2700 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 58,581 psi | 90% | 2835 fps | 99.2% |
| Ramshot Hunter | <<locked>> | 90% | 55,245 psi | 85% | 2717 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 52,591 psi | 81% | 2717 fps | 99.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,478 psi | 58% | 1680 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 58,581 psi | 90% | 2690 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 55,825 psi | 86% | 2733 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 58,175 psi | 89% | 2753 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 56,289 psi | 87% | 2779 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 48,124 psi | 74% | 2746 fps | 99.7% |
| Rottweil R 902 | <<locked>> | 82% | 58,247 psi | 90% | 2625 fps | 100% |
| Rottweil R 903 | <<locked>> | 84% | 55,230 psi | 85% | 2631 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 56,710 psi | 87% | 2697 fps | 98.6% |
| Rottweil R 905 | <<locked>> | 96% | 57,827 psi | 89% | 2759 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 88% | 57,667 psi | 89% | 2677 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 88% | 55,999 psi | 86% | 2648 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 56,304 psi | 87% | 2618 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 57,537 psi | 89% | 2694 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 56,637 psi | 87% | 2687 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 55,637 psi | 86% | 2513 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 55,492 psi | 85% | 2608 fps | 99.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 57,348 psi | 88% | 2756 fps | 99.5% |
| Somchem S355 | <<locked>> | 86% | 58,392 psi | 90% | 2671 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 58,392 psi | 90% | 2694 fps | 98.2% |
| Somchem S365 | <<locked>> | 92% | 56,550 psi | 87% | 2713 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 58,131 psi | 89% | 2730 fps | 99.8% |
| Vihtavuori N135 | <<locked>> | 82% | 58,653 psi | 90% | 2575 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 58,784 psi | 90% | 2595 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 56,231 psi | 87% | 2602 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 58,711 psi | 90% | 2703 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 57,522 psi | 88% | 2710 fps | 99.7% |
| Vihtavuori N540 | <<locked>> | 82% | 56,855 psi | 87% | 2595 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 57,522 psi | 88% | 2707 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 55,782 psi | 86% | 2726 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 55,651 psi | 86% | 2795 fps | 98.2% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 51,401 psi | 79% | 2713 fps | 97.7% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 58,160 psi | 89% | 2667 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 56,507 psi | 87% | 2730 fps | 99.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 53,156 psi | 82% | 2825 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 58,508 psi | 90% | 2730 fps | 99.5% |
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% | 53,359 psi | 82% | 2582 fps | 99.4% |
| Accurate 3100 | <<locked>> | 80% | 30,719 psi | 47% | 2231 fps | 95.8% |
| Accurate 4064 | <<locked>> | 80% | 53,606 psi | 82% | 2566 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 41,481 psi | 64% | 2470 fps | 99.7% |
| Accurate MAGPRO | 57.8 gr | 90% | 44,237 psi | 68% | 2602 fps | 95% |
| ADI AR 2208 | <<locked>> | 80% | 49,937 psi | 77% | 2546 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 37,391 psi | 58% | 2405 fps | 95.3% |
| ADI AR 2213 | <<locked>> | 90% | 43,352 psi | 67% | 2556 fps | 95.8% |
| ADI AR 2217 | <<locked>> | 98% | 41,379 psi | 64% | 2510 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 96% | 34,360 psi | 53% | 2415 fps | 96.1% |
| Alliant Power Pro Varmint | <<locked>> | 82% | 37,463 psi | 58% | 2405 fps | 95.4% |
| Alliant Power Pro Varmint | <<locked>> | 82% | 37,463 psi | 58% | 2405 fps | 95.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 50,763 psi | 78% | 2569 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 54,099 psi | 83% | 2635 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 40,089 psi | 62% | 2480 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 45,788 psi | 70% | 2592 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 37,101 psi | 57% | 2398 fps | 95.3% |
| Alliant Reloder-22 | <<locked>> | 86% | 37,492 psi | 58% | 2448 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,646 psi | 46% | 2260 fps | 98.8% |
| Alliant Reloder-25 | <<locked>> | 84% | 29,544 psi | 45% | 2277 fps | 95.8% |
| Alliant Reloder-26 | <<locked>> | 80% | 31,908 psi | 49% | 2379 fps | 97.8% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 55,129 psi | 85% | 2690 fps | 95.5% |
| Bofors RP15 | <<locked>> | 88% | 37,217 psi | 57% | 2441 fps | 95.3% |
| Bofors RP3 | <<locked>> | 80% | 51,605 psi | 79% | 2585 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 39,392 psi | 61% | 2523 fps | 95.4% |
| Bofors RP5 | <<locked>> | 86% | 37,492 psi | 58% | 2448 fps | 95.6% |
| Bofors RP7 | <<locked>> | 80% | 44,860 psi | 69% | 2477 fps | 98.4% |
| Hodgdon H1000 | <<locked>> | 94% | 39,566 psi | 61% | 2477 fps | 95.3% |
| Hodgdon H380 | <<locked>> | 80% | 51,706 psi | 80% | 2602 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 43,337 psi | 67% | 2516 fps | 98.6% |
| Hodgdon H4350 | <<locked>> | 80% | 46,195 psi | 71% | 2533 fps | 98.1% |
| Hodgdon H4831 | <<locked>> | 88% | 43,279 psi | 67% | 2507 fps | 95.1% |
| Hodgdon H4831 SC | <<locked>> | 90% | 45,469 psi | 70% | 2546 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 37,797 psi | 58% | 2379 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 37,173 psi | 57% | 2516 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 42,308 psi | 65% | 2533 fps | 98.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,601 psi | 42% | 1467 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 52,562 psi | 81% | 2575 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 54,694 psi | 84% | 2612 fps | 99.8% |
| IMR 4350 | <<locked>> | 80% | 40,553 psi | 62% | 2415 fps | 97.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 46,166 psi | 71% | 2500 fps | 98.9% |
| IMR 4831 | <<locked>> | 80% | 39,726 psi | 61% | 2425 fps | 99.6% |
| IMR 4955 Enduron | <<locked>> | 86% | 42,482 psi | 65% | 2454 fps | 95% |
| IMR 7828 SSC | <<locked>> | 90% | 41,452 psi | 64% | 2530 fps | 95.3% |
| Lovex S062 | <<locked>> | 80% | 52,910 psi | 81% | 2572 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 43,947 psi | 68% | 2457 fps | 99.4% |
| Lovex S070 | <<locked>> | 80% | 42,148 psi | 65% | 2444 fps | 98.4% |
| Lovex S071 | <<locked>> | 84% | 30,168 psi | 46% | 2218 fps | 95.6% |
| Norma 203B | <<locked>> | 80% | 53,461 psi | 82% | 2621 fps | 100% |
| Norma 204 | <<locked>> | 80% | 40,103 psi | 62% | 2441 fps | 96.1% |
| Norma MRP | 51.7 gr | 82% | 34,258 psi | 53% | 2402 fps | 95.9% |
| Norma URP | <<locked>> | 80% | 41,017 psi | 63% | 2461 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 80% | 54,273 psi | 83% | 2651 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 41,191 psi | 63% | 2539 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 39,798 psi | 61% | 2454 fps | 98.5% |
| Ramshot Magnum | <<locked>> | 88% | 34,026 psi | 52% | 2365 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,137 psi | 43% | 1503 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 51,503 psi | 79% | 2589 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 48,573 psi | 75% | 2635 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 41,205 psi | 63% | 2487 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 39,769 psi | 61% | 2503 fps | 99.4% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 33,924 psi | 52% | 2431 fps | 95.7% |
| Rottweil R 902 | <<locked>> | 80% | 54,737 psi | 84% | 2579 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 48,544 psi | 75% | 2536 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 41,249 psi | 63% | 2438 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 82% | 36,448 psi | 56% | 2385 fps | 95.3% |
| Rottweil R 907 | <<locked>> | 80% | 44,860 psi | 69% | 2477 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 80% | 43,947 psi | 68% | 2457 fps | 99.4% |
| Shooters World Precision | <<locked>> | 80% | 52,910 psi | 81% | 2572 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 42,148 psi | 65% | 2444 fps | 98.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 49,690 psi | 76% | 2589 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 49,197 psi | 76% | 2428 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 42,844 psi | 66% | 2405 fps | 98.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 36,114 psi | 56% | 2382 fps | 95.1% |
| Somchem S355 | <<locked>> | 80% | 48,646 psi | 75% | 2533 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 44,802 psi | 69% | 2480 fps | 95.5% |
| Somchem S365 | <<locked>> | 80% | 37,768 psi | 58% | 2425 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 34,722 psi | 53% | 2323 fps | 95.6% |
| Vihtavuori N135 | <<locked>> | 80% | 55,303 psi | 85% | 2536 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 55,230 psi | 85% | 2552 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 46,412 psi | 71% | 2464 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 42,351 psi | 65% | 2457 fps | 99.7% |
| Vihtavuori N165 | <<locked>> | 86% | 36,521 psi | 56% | 2356 fps | 95.8% |
| Vihtavuori N540 | <<locked>> | 80% | 53,461 psi | 82% | 2552 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,843 psi | 64% | 2464 fps | 99.6% |
| Vihtavuori N555 | <<locked>> | 80% | 33,112 psi | 51% | 2333 fps | 98.8% |
| Vihtavuori N560 | 55.5 gr | 88% | 42,496 psi | 65% | 2566 fps | 95.1% |
| Vihtavuori N565 | <<locked>> | 94% | 41,800 psi | 64% | 2546 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 41,307 psi | 64% | 2428 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 43,337 psi | 67% | 2516 fps | 98.6% |
| Winchester StaBALL HD | <<locked>> | 80% | 26,179 psi | 40% | 2257 fps | 98.6% |
| Winchester Supreme 780 | <<locked>> | 86% | 38,580 psi | 59% | 2405 fps | 95.8% |
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 92 powders for .280 Ackley Improved loaded with the .284 | 175gr | Speer Grand Slam. Accurate MAGPRO delivers the highest muzzle velocity at 2,838 fps; across all powders the maximum-charge window runs from 1,644 fps to 2,838 fps. ADI AR 2217 gives the best case fill at 100 %, and 92 of the 92 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 1:12.0 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 .284 | 175gr | Speer Grand Slam 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.