Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 127gr | Hasler Hunting bullet and 98 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 60, Alliant Reloder-17 and Winchester 760.
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 2015 | <<locked>> | 84% | 57,261 psi | 88% | 2986 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 56,028 psi | 86% | 3005 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 58,175 psi | 89% | 3081 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 55,347 psi | 85% | 3012 fps | 97% |
| Accurate 3100ᴾ | <<locked>> | 100% | 43,511 psi | 67% | 2887 fps | 96.2% |
| Accurate 4064 | <<locked>> | 90% | 56,231 psi | 87% | 3058 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 56,927 psi | 88% | 3153 fps | 99.7% |
| ADI AR 2206H | <<locked>> | 86% | 56,478 psi | 87% | 3094 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 57,914 psi | 89% | 3097 fps | 99.9% |
| ADI Benchmark 8208 | <<locked>> | 84% | 55,477 psi | 85% | 3041 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 56,579 psi | 87% | 3015 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 56,942 psi | 88% | 3228 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 58,015 psi | 89% | 3117 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 58,566 psi | 90% | 3143 fps | 100% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 57,870 psi | 89% | 3215 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 94% | 55,854 psi | 86% | 3196 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 41,452 psi | 64% | 2923 fps | 99% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 46,847 psi | 72% | 3100 fps | 98.5% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 56,913 psi | 88% | 3114 fps | 99.7% |
| Bofors RP3 | <<locked>> | 92% | 58,784 psi | 90% | 3133 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 58,697 psi | 90% | 3107 fps | 97.8% |
| Hodgdon Benchmark | <<locked>> | 84% | 56,971 psi | 88% | 3022 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 55,172 psi | 85% | 3074 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 57,305 psi | 88% | 3179 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 90% | 55,999 psi | 86% | 3094 fps | 99.4% |
| Hodgdon H414 | <<locked>> | 96% | 56,014 psi | 86% | 3150 fps | 98% |
| Hodgdon H4350 | <<locked>> | 94% | 56,492 psi | 87% | 3110 fps | 96.8% |
| Hodgdon H4895 | <<locked>> | 86% | 57,087 psi | 88% | 3104 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 54,201 psi | 83% | 3077 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 57,246 psi | 88% | 3143 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 56,985 psi | 88% | 3192 fps | 97.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,592 psi | 55% | 1909 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 58,624 psi | 90% | 3110 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 57,537 psi | 89% | 3091 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 57,334 psi | 88% | 3081 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 88% | 57,072 psi | 88% | 3058 fps | 98% |
| IMR 4350 | <<locked>> | 98% | 55,753 psi | 86% | 3077 fps | 97.4% |
| IMR 4451 Enduron | <<locked>> | 94% | 57,159 psi | 88% | 3087 fps | 98% |
| IMR 4831ᴾ | <<locked>> | 100% | 57,319 psi | 88% | 3140 fps | 99.8% |
| IMR 4895 | <<locked>> | 88% | 56,420 psi | 87% | 3120 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 55,477 psi | 85% | 3041 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 56,724 psi | 87% | 3068 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 55,883 psi | 86% | 3018 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 57,014 psi | 88% | 3071 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 56,405 psi | 87% | 3074 fps | 98.9% |
| Lovex S070 | <<locked>> | 98% | 57,696 psi | 89% | 3117 fps | 98.4% |
| Norma 201 | <<locked>> | 88% | 58,711 psi | 90% | 3087 fps | 100% |
| Norma 202 | <<locked>> | 86% | 55,941 psi | 86% | 3038 fps | 100% |
| Norma 203B | <<locked>> | 90% | 57,740 psi | 89% | 3127 fps | 100% |
| Norma 204 | <<locked>> | 98% | 56,666 psi | 87% | 3133 fps | 96.3% |
| Norma URP | <<locked>> | 98% | 55,985 psi | 86% | 3140 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 88% | 54,969 psi | 85% | 3097 fps | 99.9% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 58,494 psi | 90% | 3192 fps | 99% |
| Ramshot TAC | <<locked>> | 84% | 55,985 psi | 86% | 3064 fps | 99% |
| Ramshot Wild Boar | <<locked>> | 84% | 55,782 psi | 86% | 3081 fps | 99.9% |
| Ramshot X-Terminator | <<locked>> | 82% | 56,362 psi | 87% | 3045 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,071 psi | 55% | 1955 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 58,552 psi | 90% | 3074 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 56,202 psi | 86% | 3074 fps | 98.4% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 55,724 psi | 86% | 3159 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 55,463 psi | 85% | 3192 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 56,956 psi | 88% | 3179 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 56,188 psi | 86% | 3209 fps | 99.5% |
| Rottweil R 901 | <<locked>> | 84% | 55,695 psi | 86% | 3015 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 55,550 psi | 85% | 3031 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 58,639 psi | 90% | 3123 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 58,697 psi | 90% | 3107 fps | 97.8% |
| Shooters World Long Rifle | <<locked>> | 96% | 56,405 psi | 87% | 3074 fps | 98.9% |
| Shooters World Match Rifle | <<locked>> | 86% | 56,724 psi | 87% | 3068 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 57,014 psi | 88% | 3071 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 57,696 psi | 89% | 3117 fps | 98.4% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 57,145 psi | 88% | 3140 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 58,247 psi | 90% | 3100 fps | 99.5% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 58,755 psi | 90% | 3117 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 56,681 psi | 87% | 2976 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 57,319 psi | 88% | 2972 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 56,768 psi | 87% | 3025 fps | 98% |
| Somchem S321 | <<locked>> | 82% | 56,768 psi | 87% | 3074 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 55,985 psi | 86% | 2969 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 58,001 psi | 89% | 3091 fps | 100% |
| Somchem S355 | <<locked>> | 94% | 58,784 psi | 90% | 3120 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 54,114 psi | 83% | 3140 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 49,966 psi | 77% | 3009 fps | 96.1% |
| Vihtavuori N130 | <<locked>> | 82% | 56,318 psi | 87% | 2933 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 57,043 psi | 88% | 2956 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 55,550 psi | 85% | 2995 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 56,579 psi | 87% | 3015 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 56,753 psi | 87% | 3045 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 58,494 psi | 90% | 3136 fps | 99.7% |
| Vihtavuori N530 | <<locked>> | 84% | 56,057 psi | 86% | 3045 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 58,378 psi | 90% | 3061 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 57,377 psi | 88% | 3136 fps | 99.6% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 45,788 psi | 70% | 3005 fps | 98.9% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 55,129 psi | 85% | 3058 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 56,231 psi | 87% | 3091 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 56,333 psi | 87% | 3153 fps | 98% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 37,028 psi | 57% | 2923 fps | 99% |
| Winchester StaBALL Match | <<locked>> | 86% | 55,100 psi | 85% | 3071 fps | 100% |
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 2015 | <<locked>> | 80% | 50,343 psi | 77% | 2884 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 42,830 psi | 66% | 2795 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 50,546 psi | 78% | 2966 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 48,530 psi | 75% | 2890 fps | 95.5% |
| Accurate 3100 | <<locked>> | 98% | 40,538 psi | 62% | 2828 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 40,509 psi | 62% | 2789 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 34,447 psi | 53% | 2710 fps | 95.1% |
| ADI AR 2206H | <<locked>> | 80% | 46,731 psi | 72% | 2923 fps | 99.3% |
| ADI AR 2208 | <<locked>> | 80% | 39,566 psi | 61% | 2756 fps | 97.4% |
| ADI Benchmark 8208 | <<locked>> | 80% | 48,907 psi | 75% | 2933 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 80% | 49,632 psi | 76% | 2917 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 42,859 psi | 66% | 2956 fps | 98.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 39,421 psi | 61% | 2782 fps | 98.7% |
| Alliant Reloder-15 | <<locked>> | 80% | 42,351 psi | 65% | 2851 fps | 98.2% |
| Alliant Reloder-16 | <<locked>> | 84% | 34,722 psi | 53% | 2733 fps | 95.3% |
| Alliant Reloder-17 | 51.5 gr | 80% | 34,127 psi | 53% | 2743 fps | 96.9% |
| Alliant Reloder-23 | <<locked>> | 92% | 31,995 psi | 49% | 2677 fps | 95.9% |
| Alliant Reloder-26 | <<locked>> | 94% | 37,637 psi | 58% | 2887 fps | 95.7% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 46,195 psi | 71% | 2927 fps | 98.5% |
| Bofors RP3 | <<locked>> | 80% | 39,044 psi | 60% | 2782 fps | 98.7% |
| Bofors RP7 | <<locked>> | 90% | 48,515 psi | 75% | 2930 fps | 95.7% |
| Hodgdon Benchmark | <<locked>> | 80% | 50,372 psi | 77% | 2920 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 48,080 psi | 74% | 2953 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 53,447 psi | 82% | 3117 fps | 99.7% |
| Hodgdon H380 | <<locked>> | 80% | 39,813 psi | 61% | 2785 fps | 96.4% |
| Hodgdon H414 | <<locked>> | 90% | 45,614 psi | 70% | 2959 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 90% | 49,574 psi | 76% | 2989 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 47,224 psi | 73% | 2936 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 29,834 psi | 46% | 2562 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 43,511 psi | 67% | 2907 fps | 99.5% |
| Hodgdon Superformance | <<locked>> | 90% | 45,585 psi | 70% | 2979 fps | 95.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,310 psi | 40% | 1706 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 45,208 psi | 70% | 2881 fps | 99.4% |
| IMR 3031 | <<locked>> | 80% | 47,021 psi | 72% | 2927 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 41,568 psi | 64% | 2795 fps | 98.1% |
| IMR 4166 Enduron | <<locked>> | 80% | 44,005 psi | 68% | 2815 fps | 95.1% |
| IMR 4350 | <<locked>> | 92% | 45,905 psi | 71% | 2900 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 86% | 44,396 psi | 68% | 2851 fps | 95.1% |
| IMR 4831 | <<locked>> | 86% | 35,853 psi | 55% | 2726 fps | 95.7% |
| IMR 4895 | <<locked>> | 80% | 43,439 psi | 67% | 2884 fps | 98.9% |
| IMR 8208 XBR | <<locked>> | 80% | 48,907 psi | 75% | 2933 fps | 99.9% |
| Lovex D073.6 | <<locked>> | 80% | 46,122 psi | 71% | 2900 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 46,398 psi | 71% | 2854 fps | 99.3% |
| Lovex S062 | <<locked>> | 80% | 41,408 psi | 64% | 2795 fps | 99.3% |
| Lovex S065 | <<locked>> | 84% | 38,638 psi | 59% | 2733 fps | 95% |
| Lovex S070 | <<locked>> | 90% | 44,541 psi | 69% | 2877 fps | 95.6% |
| Norma 201 | <<locked>> | 80% | 45,498 psi | 70% | 2867 fps | 99.7% |
| Norma 202 | <<locked>> | 80% | 46,151 psi | 71% | 2881 fps | 100% |
| Norma 203B | <<locked>> | 80% | 41,698 psi | 64% | 2838 fps | 98.5% |
| Norma 204 | <<locked>> | 96% | 52,765 psi | 81% | 3064 fps | 95.4% |
| Norma URP | <<locked>> | 84% | 34,954 psi | 54% | 2717 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 80% | 41,582 psi | 64% | 2854 fps | 98.4% |
| Ramshot Hunter | <<locked>> | 90% | 41,713 psi | 64% | 2884 fps | 95.5% |
| Ramshot TAC | <<locked>> | 80% | 48,834 psi | 75% | 2940 fps | 97.9% |
| Ramshot Wild Boar | <<locked>> | 80% | 48,472 psi | 75% | 2959 fps | 99.5% |
| Ramshot X-Terminator | <<locked>> | 80% | 52,794 psi | 81% | 2986 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,818 psi | 41% | 1749 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 54,708 psi | 84% | 3018 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 43,047 psi | 66% | 2831 fps | 95.6% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 45,078 psi | 69% | 2969 fps | 98.7% |
| ReloadSwiss RS 60 | 51.5 gr | 80% | 36,361 psi | 56% | 2818 fps | 99.5% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 37,057 psi | 57% | 2795 fps | 95.7% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 39,537 psi | 61% | 2867 fps | 95.8% |
| Rottweil R 901 | <<locked>> | 80% | 49,342 psi | 76% | 2913 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 43,236 psi | 67% | 2815 fps | 99.5% |
| Rottweil R 903 | <<locked>> | 80% | 36,608 psi | 56% | 2720 fps | 97.9% |
| Rottweil R 907 | <<locked>> | 90% | 48,515 psi | 75% | 2930 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 84% | 38,638 psi | 59% | 2733 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 46,122 psi | 71% | 2900 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 41,408 psi | 64% | 2795 fps | 99.3% |
| Shooters World SW4350 | <<locked>> | 90% | 44,541 psi | 69% | 2877 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 37,942 psi | 58% | 2779 fps | 97.5% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 47,036 psi | 72% | 2907 fps | 98% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 45,295 psi | 70% | 2887 fps | 99.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 46,862 psi | 72% | 2822 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 39,102 psi | 60% | 2674 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 43,526 psi | 67% | 2792 fps | 95.1% |
| Somchem S321 | <<locked>> | 80% | 53,069 psi | 82% | 3015 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 46,470 psi | 71% | 2818 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 47,007 psi | 72% | 2907 fps | 99.3% |
| Somchem S355 | <<locked>> | 80% | 37,463 psi | 58% | 2726 fps | 97.9% |
| Somchem S365 | <<locked>> | 80% | 27,137 psi | 42% | 2533 fps | 95.2% |
| Somchem S385 | <<locked>> | 98% | 46,775 psi | 72% | 2949 fps | 95.3% |
| Vihtavuori N130 | <<locked>> | 80% | 52,866 psi | 81% | 2884 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 47,311 psi | 73% | 2812 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 43,018 psi | 66% | 2799 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 43,555 psi | 67% | 2805 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 35,607 psi | 55% | 2657 fps | 98.6% |
| Vihtavuori N160 | <<locked>> | 84% | 36,419 psi | 56% | 2723 fps | 95.6% |
| Vihtavuori N530 | <<locked>> | 80% | 49,023 psi | 75% | 2930 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 41,989 psi | 65% | 2792 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 35,810 psi | 55% | 2720 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 90% | 32,489 psi | 50% | 2700 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 31,618 psi | 49% | 2575 fps | 96.2% |
| Winchester 748 | <<locked>> | 80% | 49,153 psi | 76% | 2979 fps | 100% |
| Winchester 760 | 56.7 gr | 90% | 45,861 psi | 71% | 2963 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 94% | 30,197 psi | 46% | 2700 fps | 95.5% |
| Winchester StaBALL Match | <<locked>> | 80% | 44,773 psi | 69% | 2890 fps | 99.4% |
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 98 powders for .280 Ackley Improved loaded with the .284 | 127gr | Hasler Hunting. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,228 fps; across all powders the maximum-charge window runs from 1,909 fps to 3,228 fps. Accurate 3100 gives the best case fill at 100 %, and 98 of the 98 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 55–90 %, leaving at least 10 % headroom. The 127.0 gr projectile in 0.284" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-16, 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. ReloadSwiss RS 60, Alliant Reloder-17, Winchester 760 rank at the top here: for .280 Ackley Improved with the .284 | 127gr | Hasler Hunting 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.