Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 160gr | Winchester Silvertip bullet and 88 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 Alliant Reloder-26.
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% | 56,724 psi | 87% | 2762 fps | 99.4% |
| Accurate 3100 | <<locked>> | 98% | 55,927 psi | 86% | 2818 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 56,710 psi | 87% | 2743 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 57,725 psi | 89% | 2858 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 58,305 psi | 90% | 2966 fps | 97.6% |
| ADI AR 2208 | <<locked>> | 84% | 56,086 psi | 86% | 2772 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 58,624 psi | 90% | 2910 fps | 99.2% |
| ADI AR 2213 | <<locked>> | 98% | 56,188 psi | 86% | 2907 fps | 98.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 38,696 psi | 60% | 2628 fps | 97.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 57,203 psi | 88% | 2795 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 57,348 psi | 88% | 2818 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 58,494 psi | 90% | 2910 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 56,101 psi | 86% | 2877 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 57,885 psi | 89% | 2897 fps | 99.2% |
| Alliant Reloder-22 | <<locked>> | 98% | 55,666 psi | 86% | 2904 fps | 99% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 56,434 psi | 87% | 2881 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 48,718 psi | 75% | 2822 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 96% | 56,739 psi | 87% | 2969 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 54,520 psi | 84% | 2887 fps | 98.8% |
| Bofors RP3 | <<locked>> | 84% | 58,363 psi | 90% | 2815 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 44,730 psi | 69% | 2749 fps | 96.3% |
| Bofors RP5 | <<locked>> | 98% | 55,666 psi | 86% | 2904 fps | 99% |
| Bofors RP7 | <<locked>> | 88% | 57,246 psi | 88% | 2805 fps | 99.6% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 48,182 psi | 74% | 2766 fps | 97.3% |
| Hodgdon H380 | <<locked>> | 84% | 58,566 psi | 90% | 2835 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 55,898 psi | 86% | 2854 fps | 99.7% |
| Hodgdon H4350 | <<locked>> | 86% | 55,506 psi | 85% | 2818 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 96% | 56,333 psi | 87% | 2851 fps | 97.5% |
| Hodgdon H4831 SC | <<locked>> | 96% | 55,172 psi | 85% | 2835 fps | 97.3% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 55,201 psi | 85% | 2785 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 47,688 psi | 73% | 2867 fps | 98.6% |
| Hodgdon Superformance | <<locked>> | 88% | 56,246 psi | 87% | 2894 fps | 99.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,767 psi | 57% | 1742 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 55,434 psi | 85% | 2753 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 57,856 psi | 89% | 2792 fps | 99.8% |
| IMR 4350 | <<locked>> | 92% | 58,479 psi | 90% | 2841 fps | 99.7% |
| IMR 4451 Enduron | <<locked>> | 86% | 55,303 psi | 85% | 2779 fps | 99.6% |
| IMR 4831 | <<locked>> | 92% | 58,233 psi | 90% | 2848 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 57,653 psi | 89% | 2838 fps | 97.9% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 57,580 psi | 89% | 2943 fps | 98.4% |
| Lovex S062 | <<locked>> | 82% | 56,014 psi | 86% | 2749 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 55,579 psi | 86% | 2776 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 57,101 psi | 88% | 2822 fps | 99.8% |
| Lovex S071ᴾ | <<locked>> | 100% | 49,821 psi | 77% | 2726 fps | 99.6% |
| Norma 203B | <<locked>> | 82% | 56,637 psi | 87% | 2805 fps | 100% |
| Norma 204 | <<locked>> | 90% | 55,738 psi | 86% | 2841 fps | 98.8% |
| Norma MRP | <<locked>> | 96% | 55,332 psi | 85% | 2927 fps | 99.7% |
| Norma URP | <<locked>> | 90% | 56,173 psi | 86% | 2838 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 57,493 psi | 88% | 2828 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 58,204 psi | 90% | 2963 fps | 98.8% |
| Ramshot Hunter | <<locked>> | 90% | 54,926 psi | 85% | 2841 fps | 99.9% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 52,344 psi | 81% | 2838 fps | 99.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,478 psi | 58% | 1781 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 58,276 psi | 90% | 2822 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 55,390 psi | 85% | 2864 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 57,682 psi | 89% | 2881 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 55,912 psi | 86% | 2907 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 48,008 psi | 74% | 2867 fps | 99.4% |
| Rottweil R 902 | <<locked>> | 82% | 57,769 psi | 89% | 2756 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 58,523 psi | 90% | 2812 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 56,449 psi | 87% | 2825 fps | 98.1% |
| Rottweil R 905 | <<locked>> | 96% | 57,203 psi | 88% | 2884 fps | 99.2% |
| Rottweil R 907 | <<locked>> | 88% | 57,246 psi | 88% | 2805 fps | 99.6% |
| Shooters World Long Rifle | <<locked>> | 88% | 55,579 psi | 86% | 2776 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 56,014 psi | 86% | 2749 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 57,101 psi | 88% | 2822 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 56,144 psi | 86% | 2818 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 55,129 psi | 85% | 2641 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 55,201 psi | 85% | 2733 fps | 99.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 56,724 psi | 87% | 2877 fps | 99.1% |
| Somchem S355 | <<locked>> | 86% | 58,218 psi | 90% | 2805 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 58,204 psi | 90% | 2818 fps | 97.7% |
| Somchem S365 | <<locked>> | 92% | 56,057 psi | 86% | 2841 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 57,943 psi | 89% | 2858 fps | 99.6% |
| Vihtavuori N135 | <<locked>> | 82% | 58,291 psi | 90% | 2710 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 58,349 psi | 90% | 2726 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 55,927 psi | 86% | 2730 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 58,117 psi | 89% | 2831 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 57,334 psi | 88% | 2835 fps | 99.4% |
| Vihtavuori N540 | <<locked>> | 82% | 56,434 psi | 87% | 2726 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 57,334 psi | 88% | 2838 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 55,288 psi | 85% | 2854 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 55,390 psi | 85% | 2920 fps | 97.7% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 50,908 psi | 78% | 2828 fps | 97% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 58,015 psi | 89% | 2799 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 56,173 psi | 86% | 2858 fps | 99.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 52,736 psi | 81% | 2956 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 58,001 psi | 89% | 2854 fps | 99.1% |
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% | 53,258 psi | 82% | 2710 fps | 99% |
| Accurate 3100 | <<locked>> | 82% | 32,590 psi | 50% | 2385 fps | 95.8% |
| Accurate 4064 | <<locked>> | 80% | 53,156 psi | 82% | 2694 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 41,191 psi | 63% | 2585 fps | 99.4% |
| Accurate MAGPRO | <<locked>> | 92% | 47,210 psi | 73% | 2779 fps | 95% |
| ADI AR 2208 | <<locked>> | 80% | 49,632 psi | 76% | 2674 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 39,566 psi | 61% | 2566 fps | 95.2% |
| ADI AR 2213 | <<locked>> | 92% | 45,963 psi | 71% | 2730 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 98% | 36,332 psi | 56% | 2569 fps | 96% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 50,560 psi | 78% | 2697 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 53,780 psi | 83% | 2766 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 39,740 psi | 61% | 2595 fps | 99.5% |
| Alliant Reloder-17 | <<locked>> | 80% | 45,310 psi | 70% | 2713 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 39,407 psi | 61% | 2562 fps | 95.3% |
| Alliant Reloder-22 | <<locked>> | 88% | 39,827 psi | 61% | 2615 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,370 psi | 45% | 2359 fps | 98.1% |
| Alliant Reloder-25 | <<locked>> | 86% | 31,198 psi | 48% | 2428 fps | 95.7% |
| Alliant Reloder-26 | 55.4 gr | 80% | 31,575 psi | 49% | 2474 fps | 96.8% |
| Bofors RP15 | <<locked>> | 90% | 39,349 psi | 61% | 2602 fps | 95.2% |
| Bofors RP3 | <<locked>> | 80% | 51,213 psi | 79% | 2713 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 41,800 psi | 64% | 2687 fps | 95.4% |
| Bofors RP5 | <<locked>> | 88% | 39,827 psi | 61% | 2615 fps | 95.6% |
| Bofors RP7 | <<locked>> | 80% | 44,730 psi | 69% | 2595 fps | 97.8% |
| Hodgdon H1000 | <<locked>> | 96% | 42,105 psi | 65% | 2644 fps | 95.4% |
| Hodgdon H380 | <<locked>> | 80% | 51,227 psi | 79% | 2726 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 43,091 psi | 66% | 2631 fps | 98% |
| Hodgdon H4350 | <<locked>> | 80% | 45,788 psi | 70% | 2648 fps | 97.4% |
| Hodgdon H4831 | <<locked>> | 90% | 46,079 psi | 71% | 2677 fps | 95.1% |
| Hodgdon H4831 SC | <<locked>> | 92% | 48,240 psi | 74% | 2717 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 37,275 psi | 57% | 2484 fps | 99.7% |
| Hodgdon Retumbo | <<locked>> | 94% | 39,421 psi | 61% | 2680 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 41,916 psi | 64% | 2648 fps | 97.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,601 psi | 42% | 1558 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 52,243 psi | 80% | 2707 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 54,346 psi | 84% | 2740 fps | 99.6% |
| IMR 4350 | <<locked>> | 80% | 40,118 psi | 62% | 2523 fps | 96.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 46,021 psi | 71% | 2621 fps | 98.4% |
| IMR 4831 | <<locked>> | 80% | 39,450 psi | 61% | 2536 fps | 99.2% |
| IMR 4955 Enduron | <<locked>> | 88% | 44,991 psi | 69% | 2621 fps | 95% |
| IMR 7828 SSC | <<locked>> | 92% | 43,990 psi | 68% | 2703 fps | 95.3% |
| Lovex S062 | <<locked>> | 80% | 52,562 psi | 81% | 2700 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 43,584 psi | 67% | 2572 fps | 99% |
| Lovex S070 | <<locked>> | 80% | 41,930 psi | 65% | 2559 fps | 97.9% |
| Lovex S071 | <<locked>> | 86% | 31,937 psi | 49% | 2369 fps | 95.5% |
| Norma 203B | <<locked>> | 80% | 53,113 psi | 82% | 2749 fps | 100% |
| Norma 204 | <<locked>> | 80% | 39,813 psi | 61% | 2552 fps | 95.2% |
| Norma MRP | 56.4 gr | 84% | 36,303 psi | 56% | 2562 fps | 95.9% |
| Norma URP | <<locked>> | 80% | 40,785 psi | 63% | 2579 fps | 99.3% |
| Ramshot Big Game | <<locked>> | 80% | 53,954 psi | 83% | 2779 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 43,801 psi | 67% | 2710 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 39,508 psi | 61% | 2566 fps | 97.9% |
| Ramshot Magnum | <<locked>> | 90% | 36,376 psi | 56% | 2530 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,094 psi | 43% | 1594 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 51,184 psi | 79% | 2713 fps | 99.6% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 48,095 psi | 74% | 2759 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 41,031 psi | 63% | 2605 fps | 99.2% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 39,494 psi | 61% | 2615 fps | 98.9% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 36,071 psi | 55% | 2595 fps | 95.8% |
| Rottweil R 902 | <<locked>> | 80% | 54,447 psi | 84% | 2710 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 48,298 psi | 74% | 2661 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 43,758 psi | 67% | 2605 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 84% | 38,609 psi | 59% | 2546 fps | 95.2% |
| Rottweil R 907 | <<locked>> | 80% | 44,730 psi | 69% | 2595 fps | 97.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 43,584 psi | 67% | 2572 fps | 99% |
| Shooters World Precision | <<locked>> | 80% | 52,562 psi | 81% | 2700 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 41,930 psi | 65% | 2559 fps | 97.9% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 49,400 psi | 76% | 2713 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 48,878 psi | 75% | 2556 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 42,569 psi | 65% | 2520 fps | 97.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 38,261 psi | 59% | 2539 fps | 95.1% |
| Somchem S355 | <<locked>> | 80% | 48,269 psi | 74% | 2657 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 47,805 psi | 74% | 2651 fps | 95.6% |
| Somchem S365 | <<locked>> | 80% | 37,246 psi | 57% | 2533 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 36,753 psi | 57% | 2477 fps | 95.5% |
| Vihtavuori N135 | <<locked>> | 80% | 54,868 psi | 84% | 2667 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 55,042 psi | 85% | 2684 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 46,253 psi | 71% | 2589 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 42,076 psi | 65% | 2575 fps | 99.5% |
| Vihtavuori N165 | <<locked>> | 88% | 38,682 psi | 60% | 2516 fps | 95.8% |
| Vihtavuori N540 | <<locked>> | 80% | 53,011 psi | 82% | 2677 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,423 psi | 64% | 2572 fps | 99.3% |
| Vihtavuori N555 | <<locked>> | 80% | 32,735 psi | 50% | 2434 fps | 98.1% |
| Vihtavuori N560 | 60.5 gr | 90% | 45,165 psi | 69% | 2736 fps | 95.2% |
| Vihtavuori N565 | <<locked>> | 96% | 44,570 psi | 69% | 2717 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 41,002 psi | 63% | 2539 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 43,091 psi | 66% | 2631 fps | 98% |
| Winchester StaBALL HD | <<locked>> | 80% | 25,991 psi | 40% | 2346 fps | 97.5% |
| Winchester Supreme 780 | <<locked>> | 88% | 41,220 psi | 63% | 2572 fps | 95.9% |
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 94 powders for .280 Ackley Improved loaded with the .284 | 160gr | Winchester Silvertip. Alliant Reloder-26 delivers the highest muzzle velocity at 2,969 fps; across all powders the maximum-charge window runs from 1,742 fps to 2,969 fps. ADI AR 2217 gives the best case fill at 100 %, and 94 of the 94 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 53–90 %, leaving at least 10 % headroom. The 160.0 gr projectile in 0.284" calls for a 1:16.0 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, Alliant Reloder-26 rank at the top here: for .280 Ackley Improved with the .284 | 160gr | Winchester Silvertip 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.