Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 145gr | Speer Grand Slam bullet and 103 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 70, Alliant Reloder-16 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.
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>> | 84% | 57,841 psi | 89% | 2838 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 55,361 psi | 85% | 2854 fps | 98.4% |
| Accurate 3100ᴾ | <<locked>> | 100% | 53,011 psi | 82% | 2894 fps | 99.3% |
| Accurate 4064 | <<locked>> | 86% | 58,073 psi | 89% | 2890 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 55,013 psi | 85% | 2946 fps | 100% |
| ADI AR 2206H | <<locked>> | 82% | 57,058 psi | 88% | 2920 fps | 100% |
| ADI AR 2208 | <<locked>> | 88% | 58,059 psi | 89% | 2927 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 56,231 psi | 87% | 2989 fps | 98% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 53,679 psi | 83% | 2972 fps | 96.2% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 57,769 psi | 89% | 3054 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 55,419 psi | 85% | 2897 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 55,608 psi | 86% | 2917 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 55,970 psi | 86% | 3005 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 90% | 57,435 psi | 88% | 3031 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 55,376 psi | 85% | 2972 fps | 97.9% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 52,446 psi | 81% | 2969 fps | 97.6% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 49,632 psi | 76% | 2910 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 43,207 psi | 66% | 2825 fps | 98.6% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 57,348 psi | 88% | 3110 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 57,043 psi | 88% | 2940 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 48,240 psi | 74% | 2894 fps | 96.5% |
| Bofors RP3 | <<locked>> | 86% | 56,405 psi | 87% | 2917 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 52,446 psi | 81% | 2969 fps | 97.6% |
| Bofors RP7 | <<locked>> | 90% | 55,535 psi | 85% | 2894 fps | 98.6% |
| Hodgdon H380 | <<locked>> | 86% | 56,884 psi | 88% | 2933 fps | 100% |
| Hodgdon H414 | <<locked>> | 92% | 57,551 psi | 89% | 3002 fps | 99.3% |
| Hodgdon H4350 | <<locked>> | 90% | 57,145 psi | 88% | 2959 fps | 98.4% |
| Hodgdon H4831ᴾ | <<locked>> | 100% | 57,928 psi | 89% | 2986 fps | 96.4% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 56,347 psi | 87% | 2959 fps | 96.1% |
| Hodgdon H4895 | <<locked>> | 82% | 57,682 psi | 89% | 2930 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 56,202 psi | 86% | 2927 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 58,088 psi | 89% | 2969 fps | 100% |
| Hodgdon Superformance | <<locked>> | 92% | 57,899 psi | 89% | 3041 fps | 99.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,230 psi | 56% | 1808 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 58,798 psi | 90% | 2933 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 58,233 psi | 90% | 2904 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 57,624 psi | 89% | 2907 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 56,695 psi | 87% | 2887 fps | 99.1% |
| IMR 4350 | <<locked>> | 94% | 56,637 psi | 87% | 2930 fps | 98.8% |
| IMR 4451 Enduron | <<locked>> | 90% | 57,276 psi | 88% | 2923 fps | 99.2% |
| IMR 4831 | <<locked>> | 94% | 55,535 psi | 85% | 2940 fps | 100% |
| IMR 4895 | <<locked>> | 84% | 57,014 psi | 88% | 2946 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 55,724 psi | 86% | 2913 fps | 96.2% |
| Lovex D073.6 | <<locked>> | 82% | 57,406 psi | 88% | 2894 fps | 100% |
| Lovex S060 | <<locked>> | 82% | 55,782 psi | 86% | 2844 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 57,754 psi | 89% | 2900 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 57,392 psi | 88% | 2920 fps | 99.8% |
| Lovex S070 | <<locked>> | 92% | 55,129 psi | 85% | 2907 fps | 99.1% |
| Lovex S071ᴾ | <<locked>> | 100% | 44,077 psi | 68% | 2740 fps | 98% |
| Norma 201 | <<locked>> | 82% | 55,811 psi | 86% | 2864 fps | 100% |
| Norma 202 | <<locked>> | 82% | 56,289 psi | 87% | 2858 fps | 100% |
| Norma 203B | <<locked>> | 86% | 58,566 psi | 90% | 2959 fps | 100% |
| Norma 204 | <<locked>> | 94% | 57,406 psi | 88% | 2982 fps | 98% |
| Norma MRPᴾ | <<locked>> | 100% | 55,912 psi | 86% | 3061 fps | 99.2% |
| Norma URP | <<locked>> | 94% | 57,595 psi | 89% | 2986 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 55,840 psi | 86% | 2933 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 51,619 psi | 79% | 2963 fps | 96.2% |
| Ramshot Hunter | <<locked>> | 94% | 56,217 psi | 86% | 2982 fps | 99.6% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 45,788 psi | 70% | 2828 fps | 96.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,086 psi | 57% | 1854 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 56,753 psi | 87% | 2917 fps | 99.5% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 56,536 psi | 87% | 2986 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 56,710 psi | 87% | 3022 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 58,813 psi | 90% | 3025 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 57,246 psi | 88% | 3054 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 42,134 psi | 65% | 2838 fps | 96.4% |
| Rottweil R 902 | <<locked>> | 84% | 56,275 psi | 87% | 2861 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 56,260 psi | 87% | 2910 fps | 100% |
| Rottweil R 904 | <<locked>> | 98% | 57,783 psi | 89% | 2956 fps | 97.2% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 58,392 psi | 90% | 3018 fps | 98.5% |
| Rottweil R 907 | <<locked>> | 90% | 55,535 psi | 85% | 2894 fps | 98.6% |
| Shooters World Long Rifle | <<locked>> | 92% | 57,392 psi | 88% | 2920 fps | 99.8% |
| Shooters World Match Rifle | <<locked>> | 82% | 57,406 psi | 88% | 2894 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 57,754 psi | 89% | 2900 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 55,129 psi | 85% | 2907 fps | 99.1% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 57,899 psi | 89% | 2969 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 58,334 psi | 90% | 2927 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 55,303 psi | 85% | 2890 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 56,550 psi | 87% | 2792 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 57,290 psi | 88% | 2792 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 57,305 psi | 88% | 2874 fps | 99.2% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 57,885 psi | 89% | 3012 fps | 98.4% |
| Somchem S335 | <<locked>> | 82% | 56,289 psi | 87% | 2792 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 58,030 psi | 89% | 2913 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 56,173 psi | 86% | 2904 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 56,202 psi | 86% | 2897 fps | 96% |
| Somchem S365 | <<locked>> | 96% | 56,608 psi | 87% | 2986 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 55,376 psi | 85% | 2936 fps | 98.7% |
| Vihtavuori N133 | <<locked>> | 82% | 57,072 psi | 88% | 2776 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 56,782 psi | 87% | 2825 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 57,087 psi | 88% | 2841 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 57,769 psi | 89% | 2881 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 55,912 psi | 86% | 2923 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 51,126 psi | 79% | 2854 fps | 97.6% |
| Vihtavuori N540 | <<locked>> | 84% | 55,230 psi | 85% | 2835 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 55,129 psi | 85% | 2930 fps | 99.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 55,492 psi | 85% | 2989 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 56,289 psi | 87% | 3048 fps | 96.5% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 55,608 psi | 86% | 2894 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 57,551 psi | 89% | 3002 fps | 99.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 44,846 psi | 69% | 2966 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 55,680 psi | 86% | 2900 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 55,535 psi | 85% | 2930 fps | 97.8% |
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% | 50,734 psi | 78% | 2740 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 48,602 psi | 75% | 2740 fps | 97.3% |
| Accurate 3100 | <<locked>> | 88% | 35,099 psi | 54% | 2549 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 48,051 psi | 74% | 2746 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 36,506 psi | 56% | 2598 fps | 97.5% |
| ADI AR 2206H | <<locked>> | 80% | 53,447 psi | 82% | 2867 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 45,353 psi | 70% | 2713 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 92% | 46,093 psi | 71% | 2808 fps | 95.7% |
| ADI AR 2213 | <<locked>> | 98% | 50,386 psi | 78% | 2913 fps | 95.3% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 50,111 psi | 77% | 2933 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 45,890 psi | 71% | 2743 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 48,965 psi | 75% | 2812 fps | 99.9% |
| Alliant Reloder-16 | 48.9 gr | 80% | 35,694 psi | 55% | 2608 fps | 97.6% |
| Alliant Reloder-17 | <<locked>> | 80% | 40,437 psi | 62% | 2740 fps | 99.7% |
| Alliant Reloder-19 | <<locked>> | 92% | 45,585 psi | 70% | 2799 fps | 95.7% |
| Alliant Reloder-22 | <<locked>> | 94% | 42,960 psi | 66% | 2792 fps | 95.1% |
| Alliant Reloder-23 | <<locked>> | 82% | 27,934 psi | 43% | 2415 fps | 95.9% |
| Alliant Reloder-25 | <<locked>> | 92% | 33,547 psi | 52% | 2585 fps | 95% |
| Alliant Reloder-26 | 56.7 gr | 84% | 31,981 psi | 49% | 2585 fps | 95.3% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 53,214 psi | 82% | 2881 fps | 100% |
| Bofors RP15 | <<locked>> | 98% | 45,092 psi | 69% | 2831 fps | 95.6% |
| Bofors RP3 | <<locked>> | 80% | 46,282 psi | 71% | 2756 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 42,960 psi | 66% | 2792 fps | 95.1% |
| Bofors RP7 | <<locked>> | 80% | 40,727 psi | 63% | 2618 fps | 95.4% |
| Hodgdon H380 | <<locked>> | 80% | 46,557 psi | 72% | 2762 fps | 99.2% |
| Hodgdon H414 | <<locked>> | 80% | 38,464 psi | 59% | 2644 fps | 95.3% |
| Hodgdon H4350 | <<locked>> | 82% | 44,193 psi | 68% | 2726 fps | 95.7% |
| Hodgdon H4831 | <<locked>> | 98% | 54,027 psi | 83% | 2923 fps | 95.6% |
| Hodgdon H4831 SC | <<locked>> | 98% | 52,910 psi | 81% | 2904 fps | 95.3% |
| Hodgdon H4895 | <<locked>> | 80% | 54,027 psi | 83% | 2874 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 33,286 psi | 51% | 2507 fps | 98.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 50,879 psi | 78% | 2861 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 40,321 psi | 62% | 2717 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,093 psi | 42% | 1614 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 51,576 psi | 79% | 2822 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 54,650 psi | 84% | 2854 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 47,703 psi | 73% | 2749 fps | 99.8% |
| IMR 4166 Enduron | <<locked>> | 80% | 50,053 psi | 77% | 2779 fps | 98.2% |
| IMR 4350 | <<locked>> | 84% | 41,292 psi | 64% | 2654 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 80% | 42,076 psi | 65% | 2651 fps | 96.3% |
| IMR 4831 | <<locked>> | 80% | 35,201 psi | 54% | 2552 fps | 97.2% |
| IMR 4895 | <<locked>> | 80% | 50,212 psi | 77% | 2838 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 52,185 psi | 80% | 2858 fps | 95.4% |
| Lovex D073.6 | <<locked>> | 80% | 53,693 psi | 83% | 2841 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 52,330 psi | 81% | 2789 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 47,892 psi | 74% | 2746 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 39,595 psi | 61% | 2602 fps | 97.1% |
| Lovex S070 | <<locked>> | 80% | 37,942 psi | 58% | 2579 fps | 95.4% |
| Lovex S071 | <<locked>> | 94% | 36,230 psi | 56% | 2575 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 52,272 psi | 80% | 2812 fps | 100% |
| Norma 202 | <<locked>> | 80% | 52,968 psi | 81% | 2812 fps | 100% |
| Norma 203B | <<locked>> | 80% | 48,370 psi | 74% | 2799 fps | 100% |
| Norma 204 | <<locked>> | 88% | 46,847 psi | 72% | 2802 fps | 95.8% |
| Norma MRP | <<locked>> | 90% | 39,450 psi | 61% | 2743 fps | 95.5% |
| Norma URP | <<locked>> | 80% | 36,448 psi | 56% | 2598 fps | 97.4% |
| Ramshot Big Game | <<locked>> | 80% | 48,660 psi | 75% | 2822 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 48,066 psi | 74% | 2894 fps | 95.2% |
| Ramshot Hunter | <<locked>> | 80% | 35,360 psi | 54% | 2579 fps | 95.2% |
| Ramshot Magnum | <<locked>> | 98% | 42,656 psi | 66% | 2762 fps | 95.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,528 psi | 42% | 1654 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 46,514 psi | 72% | 2743 fps | 98.1% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 53,069 psi | 82% | 2933 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 42,989 psi | 66% | 2799 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 36,187 psi | 56% | 2615 fps | 97.1% |
| ReloadSwiss RS 70 | 53.5 gr | 80% | 35,346 psi | 54% | 2618 fps | 96.3% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 39,392 psi | 61% | 2769 fps | 95.2% |
| Rottweil R 902 | <<locked>> | 80% | 49,806 psi | 77% | 2762 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 43,555 psi | 67% | 2700 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 94% | 51,068 psi | 79% | 2844 fps | 95.8% |
| Rottweil R 905 | <<locked>> | 92% | 44,715 psi | 69% | 2782 fps | 95.7% |
| Rottweil R 907 | <<locked>> | 80% | 40,727 psi | 63% | 2618 fps | 95.4% |
| Shooters World Long Rifle | <<locked>> | 80% | 39,595 psi | 61% | 2602 fps | 97.1% |
| Shooters World Match Rifle | <<locked>> | 80% | 53,693 psi | 83% | 2841 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 47,892 psi | 74% | 2746 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 37,942 psi | 58% | 2579 fps | 95.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 44,628 psi | 69% | 2753 fps | 99.7% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 54,607 psi | 84% | 2871 fps | 99.8% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 52,069 psi | 80% | 2841 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 53,156 psi | 82% | 2746 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 44,889 psi | 69% | 2612 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 38,740 psi | 60% | 2543 fps | 95.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 44,295 psi | 68% | 2776 fps | 95.5% |
| Somchem S335 | <<locked>> | 80% | 52,794 psi | 81% | 2743 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 54,099 psi | 83% | 2854 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 43,787 psi | 67% | 2697 fps | 99.8% |
| Somchem S361 | <<locked>> | 94% | 52,417 psi | 81% | 2835 fps | 95.2% |
| Somchem S365 | <<locked>> | 80% | 32,779 psi | 50% | 2549 fps | 99.2% |
| Somchem S385 | <<locked>> | 88% | 39,784 psi | 61% | 2651 fps | 95.1% |
| Vihtavuori N133 | <<locked>> | 80% | 53,679 psi | 83% | 2730 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 50,067 psi | 77% | 2730 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 50,314 psi | 77% | 2743 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 41,887 psi | 64% | 2628 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 37,768 psi | 58% | 2595 fps | 97.7% |
| Vihtavuori N165 | <<locked>> | 94% | 41,829 psi | 64% | 2684 fps | 95.3% |
| Vihtavuori N540 | <<locked>> | 80% | 48,530 psi | 75% | 2733 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 37,246 psi | 57% | 2595 fps | 97.4% |
| Vihtavuori N555 | <<locked>> | 80% | 28,601 psi | 44% | 2431 fps | 95.1% |
| Vihtavuori N560 | <<locked>> | 98% | 52,576 psi | 81% | 2986 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 36,927 psi | 57% | 2566 fps | 99.3% |
| Winchester 760 | <<locked>> | 80% | 38,653 psi | 59% | 2648 fps | 95.4% |
| Winchester StaBALL HD | <<locked>> | 84% | 26,252 psi | 40% | 2438 fps | 95.5% |
| Winchester StaBALL Match | <<locked>> | 80% | 51,851 psi | 80% | 2841 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 44,904 psi | 69% | 2749 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 111 powders for .280 Ackley Improved loaded with the .284 | 145gr | Speer Grand Slam. Alliant Reloder-26 delivers the highest muzzle velocity at 3,110 fps; across all powders the maximum-charge window runs from 1,808 fps to 3,110 fps. Accurate 3100 gives the best case fill at 100 %, and 111 of the 111 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 145.0 gr projectile in 0.284" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate MAGPRO, ADI AR 2213 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. ReloadSwiss RS 70, Alliant Reloder-16, Alliant Reloder-26 rank at the top here: for .280 Ackley Improved with the .284 | 145gr | Speer Grand Slam they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2225, Baschieri & Pellagri 109, Bofors RP30 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.