Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 145gr | Speer Boat-Tail 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 60, ReloadSwiss RS 70 and Hodgdon H414.
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% | 57,551 psi | 89% | 2835 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 55,187 psi | 85% | 2851 fps | 98.4% |
| Accurate 3100ᴾ | <<locked>> | 100% | 52,547 psi | 81% | 2887 fps | 99.3% |
| Accurate 4064 | <<locked>> | 86% | 57,798 psi | 89% | 2887 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 54,795 psi | 84% | 2940 fps | 100% |
| ADI AR 2206H | <<locked>> | 82% | 56,811 psi | 87% | 2920 fps | 100% |
| ADI AR 2208 | <<locked>> | 88% | 57,885 psi | 89% | 2923 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 56,086 psi | 86% | 2986 fps | 97.9% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 53,563 psi | 82% | 2969 fps | 96.1% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 57,566 psi | 89% | 3051 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 58,653 psi | 90% | 2943 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 55,361 psi | 85% | 2913 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 55,767 psi | 86% | 3002 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 90% | 56,898 psi | 88% | 3025 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 58,740 psi | 90% | 3028 fps | 98.4% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 52,315 psi | 80% | 2969 fps | 97.5% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 49,443 psi | 76% | 2910 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 43,091 psi | 66% | 2822 fps | 98.5% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 56,826 psi | 87% | 3104 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 56,840 psi | 87% | 2936 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 48,095 psi | 74% | 2890 fps | 96.4% |
| Bofors RP3 | <<locked>> | 86% | 56,159 psi | 86% | 2913 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 52,315 psi | 80% | 2969 fps | 97.5% |
| Bofors RP7 | <<locked>> | 90% | 55,637 psi | 86% | 2894 fps | 98.6% |
| Hodgdon H380 | <<locked>> | 86% | 56,652 psi | 87% | 2930 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 92% | 57,072 psi | 88% | 2995 fps | 99.3% |
| Hodgdon H4350 | <<locked>> | 90% | 56,942 psi | 88% | 2956 fps | 98.4% |
| Hodgdon H4831ᴾ | <<locked>> | 100% | 57,406 psi | 88% | 2979 fps | 96.3% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 56,217 psi | 86% | 2956 fps | 96.1% |
| Hodgdon H4895 | <<locked>> | 82% | 57,464 psi | 88% | 2927 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 55,985 psi | 86% | 2923 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 57,856 psi | 89% | 2966 fps | 100% |
| Hodgdon Superformance | <<locked>> | 92% | 57,667 psi | 89% | 3038 fps | 99.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,390 psi | 56% | 1808 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 58,566 psi | 90% | 2930 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 58,262 psi | 90% | 2904 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 57,377 psi | 88% | 2904 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 56,782 psi | 87% | 2890 fps | 99.1% |
| IMR 4350 | <<locked>> | 94% | 56,434 psi | 87% | 2927 fps | 98.8% |
| IMR 4451 Enduron | <<locked>> | 90% | 57,087 psi | 88% | 2920 fps | 99.1% |
| IMR 4831 | <<locked>> | 94% | 55,347 psi | 85% | 2936 fps | 100% |
| IMR 4895 | <<locked>> | 84% | 56,826 psi | 87% | 2943 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 55,579 psi | 86% | 2910 fps | 96.1% |
| Lovex D073.6 | <<locked>> | 82% | 57,145 psi | 88% | 2890 fps | 100% |
| Lovex S060 | <<locked>> | 82% | 55,593 psi | 86% | 2841 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 57,537 psi | 89% | 2897 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 57,188 psi | 88% | 2920 fps | 99.8% |
| Lovex S070 | <<locked>> | 94% | 58,668 psi | 90% | 2963 fps | 99.5% |
| Lovex S071ᴾ | <<locked>> | 100% | 43,627 psi | 67% | 2733 fps | 97.8% |
| Norma 201 | <<locked>> | 82% | 55,550 psi | 85% | 2861 fps | 100% |
| Norma 202 | <<locked>> | 82% | 56,347 psi | 87% | 2858 fps | 100% |
| Norma 203B | <<locked>> | 86% | 58,334 psi | 90% | 2956 fps | 100% |
| Norma 204 | <<locked>> | 94% | 57,246 psi | 88% | 2979 fps | 98% |
| Norma MRPᴾ | <<locked>> | 100% | 55,753 psi | 86% | 3058 fps | 99.2% |
| Norma URP | <<locked>> | 94% | 57,392 psi | 88% | 2982 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 55,622 psi | 86% | 2930 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 51,198 psi | 79% | 2953 fps | 96% |
| Ramshot Hunter | <<locked>> | 94% | 55,985 psi | 86% | 2982 fps | 99.6% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 45,687 psi | 70% | 2828 fps | 96.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,014 psi | 57% | 1850 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 56,565 psi | 87% | 2913 fps | 99.5% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 56,608 psi | 87% | 2986 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 56,478 psi | 87% | 3018 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 58,639 psi | 90% | 3022 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 57,087 psi | 88% | 3051 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 42,047 psi | 65% | 2835 fps | 96.3% |
| Rottweil R 902 | <<locked>> | 84% | 56,275 psi | 87% | 2861 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 56,014 psi | 86% | 2904 fps | 100% |
| Rottweil R 904 | <<locked>> | 98% | 57,624 psi | 89% | 2953 fps | 97.1% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 58,233 psi | 90% | 3015 fps | 98.5% |
| Rottweil R 907 | <<locked>> | 90% | 55,637 psi | 86% | 2894 fps | 98.6% |
| Shooters World Long Rifle | <<locked>> | 92% | 57,188 psi | 88% | 2920 fps | 99.8% |
| Shooters World Match Rifle | <<locked>> | 82% | 57,145 psi | 88% | 2890 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 57,537 psi | 89% | 2897 fps | 100% |
| Shooters World SW4350 | <<locked>> | 94% | 58,668 psi | 90% | 2963 fps | 99.5% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 57,696 psi | 89% | 2966 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 58,117 psi | 89% | 2923 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 55,303 psi | 85% | 2890 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 56,304 psi | 87% | 2789 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 57,043 psi | 88% | 2792 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 57,130 psi | 88% | 2874 fps | 99.2% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 57,725 psi | 89% | 3012 fps | 98.4% |
| Somchem S335 | <<locked>> | 82% | 56,086 psi | 86% | 2789 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 57,841 psi | 89% | 2910 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 55,941 psi | 86% | 2900 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 56,043 psi | 86% | 2890 fps | 96% |
| Somchem S365 | <<locked>> | 96% | 56,391 psi | 87% | 2982 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 58,740 psi | 90% | 2989 fps | 99% |
| Vihtavuori N133 | <<locked>> | 82% | 56,826 psi | 87% | 2772 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 56,550 psi | 87% | 2822 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 56,884 psi | 88% | 2835 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 57,551 psi | 89% | 2877 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 55,724 psi | 86% | 2920 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 50,691 psi | 78% | 2848 fps | 97.5% |
| Vihtavuori N540 | <<locked>> | 86% | 58,639 psi | 90% | 2881 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 58,682 psi | 90% | 2982 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 55,274 psi | 85% | 2986 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 56,159 psi | 86% | 3048 fps | 96.5% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 55,434 psi | 85% | 2890 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 57,363 psi | 88% | 2999 fps | 99.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 44,672 psi | 69% | 2959 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 55,463 psi | 85% | 2897 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 55,376 psi | 85% | 2927 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% | 50,459 psi | 78% | 2736 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 48,428 psi | 75% | 2736 fps | 97.2% |
| Accurate 3100 | <<locked>> | 88% | 34,925 psi | 54% | 2546 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 47,819 psi | 74% | 2740 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 36,289 psi | 56% | 2595 fps | 97.5% |
| ADI AR 2206H | <<locked>> | 80% | 53,214 psi | 82% | 2864 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 45,382 psi | 70% | 2717 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 92% | 45,919 psi | 71% | 2805 fps | 95.6% |
| ADI AR 2213 | <<locked>> | 98% | 50,256 psi | 77% | 2910 fps | 95.3% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 49,864 psi | 77% | 2930 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 45,687 psi | 70% | 2740 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 48,747 psi | 75% | 2805 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 35,505 psi | 55% | 2605 fps | 97.5% |
| Alliant Reloder-17 | <<locked>> | 80% | 40,263 psi | 62% | 2736 fps | 99.7% |
| Alliant Reloder-19 | <<locked>> | 92% | 45,426 psi | 70% | 2795 fps | 95.7% |
| Alliant Reloder-22 | <<locked>> | 94% | 42,786 psi | 66% | 2785 fps | 95% |
| Alliant Reloder-23 | <<locked>> | 82% | 27,804 psi | 43% | 2411 fps | 95.9% |
| Alliant Reloder-25 | <<locked>> | 94% | 35,694 psi | 55% | 2644 fps | 96.1% |
| Alliant Reloder-26 | <<locked>> | 84% | 31,836 psi | 49% | 2582 fps | 95.2% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 52,997 psi | 82% | 2877 fps | 99.9% |
| Bofors RP15 | <<locked>> | 98% | 44,947 psi | 69% | 2828 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 46,035 psi | 71% | 2753 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 42,786 psi | 66% | 2785 fps | 95% |
| Bofors RP7 | <<locked>> | 80% | 40,538 psi | 62% | 2615 fps | 95.4% |
| Hodgdon H380 | <<locked>> | 80% | 46,325 psi | 71% | 2756 fps | 99.1% |
| Hodgdon H414 | 51.3 gr | 80% | 38,247 psi | 59% | 2641 fps | 95.2% |
| Hodgdon H4350 | <<locked>> | 82% | 43,990 psi | 68% | 2723 fps | 95.6% |
| Hodgdon H4831 | <<locked>> | 98% | 53,867 psi | 83% | 2920 fps | 95.6% |
| Hodgdon H4831 SC | <<locked>> | 98% | 52,736 psi | 81% | 2900 fps | 95.3% |
| Hodgdon H4895 | <<locked>> | 80% | 53,824 psi | 83% | 2874 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 33,098 psi | 51% | 2503 fps | 98.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 50,647 psi | 78% | 2858 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 40,176 psi | 62% | 2713 fps | 95.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,209 psi | 42% | 1617 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 51,619 psi | 79% | 2825 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 54,665 psi | 84% | 2854 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 47,732 psi | 73% | 2749 fps | 99.8% |
| IMR 4166 Enduron | <<locked>> | 80% | 49,850 psi | 77% | 2776 fps | 98.2% |
| IMR 4350 | <<locked>> | 84% | 41,292 psi | 64% | 2651 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 80% | 41,887 psi | 64% | 2644 fps | 96.3% |
| IMR 4831 | <<locked>> | 80% | 35,027 psi | 54% | 2549 fps | 97.2% |
| IMR 4895 | <<locked>> | 80% | 50,009 psi | 77% | 2835 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 52,040 psi | 80% | 2854 fps | 95.4% |
| Lovex D073.6 | <<locked>> | 80% | 53,722 psi | 83% | 2841 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 52,359 psi | 81% | 2792 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 47,921 psi | 74% | 2749 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 39,407 psi | 61% | 2595 fps | 97% |
| Lovex S070 | <<locked>> | 80% | 37,768 psi | 58% | 2575 fps | 95.3% |
| Lovex S071 | <<locked>> | 94% | 36,056 psi | 55% | 2572 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 52,025 psi | 80% | 2808 fps | 100% |
| Norma 202 | <<locked>> | 80% | 52,707 psi | 81% | 2805 fps | 100% |
| Norma 203B | <<locked>> | 80% | 48,124 psi | 74% | 2795 fps | 100% |
| Norma 204 | <<locked>> | 88% | 46,659 psi | 72% | 2799 fps | 95.8% |
| Norma MRP | <<locked>> | 90% | 39,247 psi | 60% | 2740 fps | 95.4% |
| Norma URP | <<locked>> | 80% | 36,274 psi | 56% | 2592 fps | 97.3% |
| Ramshot Big Game | <<locked>> | 80% | 48,443 psi | 75% | 2815 fps | 99.9% |
| Ramshot Grand | <<locked>> | 98% | 47,659 psi | 73% | 2887 fps | 95% |
| Ramshot Hunter | <<locked>> | 80% | 35,172 psi | 54% | 2575 fps | 95.1% |
| Ramshot Magnum | <<locked>> | 98% | 42,496 psi | 65% | 2759 fps | 95.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,644 psi | 43% | 1657 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 46,354 psi | 71% | 2740 fps | 98% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 52,794 psi | 81% | 2930 fps | 100% |
| ReloadSwiss RS 60 | 52.5 gr | 80% | 42,786 psi | 66% | 2792 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 36,027 psi | 55% | 2612 fps | 97.1% |
| ReloadSwiss RS 70 | 53.3 gr | 80% | 35,201 psi | 54% | 2615 fps | 96.2% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 39,276 psi | 60% | 2766 fps | 95.1% |
| Rottweil R 902 | <<locked>> | 80% | 49,603 psi | 76% | 2759 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 43,323 psi | 67% | 2697 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 94% | 50,894 psi | 78% | 2844 fps | 95.7% |
| Rottweil R 905 | <<locked>> | 92% | 44,527 psi | 69% | 2779 fps | 95.6% |
| Rottweil R 907 | <<locked>> | 80% | 40,538 psi | 62% | 2615 fps | 95.4% |
| Shooters World Long Rifle | <<locked>> | 80% | 39,407 psi | 61% | 2595 fps | 97% |
| Shooters World Match Rifle | <<locked>> | 80% | 53,722 psi | 83% | 2841 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 47,921 psi | 74% | 2749 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 37,768 psi | 58% | 2575 fps | 95.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 44,454 psi | 68% | 2749 fps | 99.7% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 54,389 psi | 84% | 2867 fps | 99.8% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 51,866 psi | 80% | 2835 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 52,910 psi | 81% | 2743 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 44,686 psi | 69% | 2608 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 38,595 psi | 59% | 2539 fps | 95.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 44,121 psi | 68% | 2776 fps | 95.5% |
| Somchem S335 | <<locked>> | 80% | 52,562 psi | 81% | 2740 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 53,940 psi | 83% | 2851 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 43,555 psi | 67% | 2694 fps | 99.8% |
| Somchem S361 | <<locked>> | 94% | 52,301 psi | 80% | 2835 fps | 95.2% |
| Somchem S365 | <<locked>> | 80% | 32,764 psi | 50% | 2549 fps | 99.2% |
| Somchem S385 | <<locked>> | 88% | 39,610 psi | 61% | 2648 fps | 95% |
| Vihtavuori N133 | <<locked>> | 80% | 53,461 psi | 82% | 2726 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 49,806 psi | 77% | 2726 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 50,096 psi | 77% | 2740 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 41,684 psi | 64% | 2625 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 37,565 psi | 58% | 2592 fps | 97.7% |
| Vihtavuori N165 | <<locked>> | 94% | 41,684 psi | 64% | 2680 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 48,327 psi | 74% | 2730 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 37,072 psi | 57% | 2592 fps | 97.3% |
| Vihtavuori N555 | <<locked>> | 80% | 28,572 psi | 44% | 2431 fps | 95% |
| Vihtavuori N560 | <<locked>> | 98% | 52,460 psi | 81% | 2982 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 36,767 psi | 57% | 2562 fps | 99.3% |
| Winchester 760 | <<locked>> | 80% | 38,450 psi | 59% | 2644 fps | 95.3% |
| Winchester StaBALL HD | <<locked>> | 84% | 26,252 psi | 40% | 2438 fps | 95.5% |
| Winchester StaBALL Match | <<locked>> | 80% | 51,924 psi | 80% | 2844 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 44,759 psi | 69% | 2746 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 Boat-Tail. Alliant Reloder-26 delivers the highest muzzle velocity at 3,104 fps; across all powders the maximum-charge window runs from 1,808 fps to 3,104 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 1:12.0 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 60, ReloadSwiss RS 70, Hodgdon H414 rank at the top here: for .280 Ackley Improved with the .284 | 145gr | Speer Boat-Tail 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.