Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 127gr | Geco ZERO bullet and 98 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Power Pro 2000-MR, Alliant Reloder-17 and ReloadSwiss RS 60.
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 2015 | <<locked>> | 84% | 56,869 psi | 87% | 2979 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 55,622 psi | 86% | 2999 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 57,798 psi | 89% | 3074 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 58,639 psi | 90% | 3058 fps | 97.5% |
| Accurate 3100ᴾ | <<locked>> | 100% | 43,236 psi | 67% | 2881 fps | 96.1% |
| Accurate 4064 | <<locked>> | 90% | 55,840 psi | 86% | 3048 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 56,260 psi | 87% | 3140 fps | 99.6% |
| ADI AR 2206H | <<locked>> | 86% | 56,115 psi | 86% | 3084 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 57,290 psi | 88% | 3084 fps | 99.9% |
| ADI Benchmark 8208 | <<locked>> | 86% | 58,639 psi | 90% | 3087 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 56,086 psi | 86% | 3005 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 56,275 psi | 87% | 3212 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 57,667 psi | 89% | 3110 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 58,218 psi | 90% | 3136 fps | 99.9% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 57,624 psi | 89% | 3205 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 94% | 55,245 psi | 85% | 3182 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 41,002 psi | 63% | 2910 fps | 98.9% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 46,369 psi | 71% | 3087 fps | 98.4% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 56,289 psi | 87% | 3100 fps | 99.7% |
| Bofors RP3 | <<locked>> | 92% | 58,407 psi | 90% | 3127 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 58,088 psi | 89% | 3094 fps | 97.6% |
| Hodgdon Benchmark | <<locked>> | 84% | 56,594 psi | 87% | 3015 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 58,407 psi | 90% | 3117 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 56,927 psi | 88% | 3173 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 90% | 55,651 psi | 86% | 3087 fps | 99.3% |
| Hodgdon H414 | <<locked>> | 96% | 55,463 psi | 85% | 3136 fps | 97.9% |
| Hodgdon H4350 | <<locked>> | 94% | 55,941 psi | 86% | 3097 fps | 96.6% |
| Hodgdon H4895 | <<locked>> | 86% | 56,695 psi | 87% | 3097 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 53,853 psi | 83% | 3068 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 56,623 psi | 87% | 3130 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 56,492 psi | 87% | 3179 fps | 97.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,476 psi | 55% | 1903 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 58,276 psi | 90% | 3104 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 57,072 psi | 88% | 3081 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 56,956 psi | 88% | 3071 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 88% | 56,739 psi | 87% | 3051 fps | 97.9% |
| IMR 4350 | <<locked>> | 98% | 55,187 psi | 85% | 3064 fps | 97.2% |
| IMR 4451 Enduron | <<locked>> | 94% | 56,594 psi | 87% | 3074 fps | 97.8% |
| IMR 4831ᴾ | <<locked>> | 100% | 57,014 psi | 88% | 3133 fps | 99.7% |
| IMR 4895 | <<locked>> | 88% | 55,753 psi | 86% | 3107 fps | 100% |
| IMR 8208 XBR | <<locked>> | 86% | 58,639 psi | 90% | 3087 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 56,028 psi | 86% | 3058 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 55,535 psi | 85% | 3009 fps | 99.9% |
| Lovex S062 | <<locked>> | 90% | 56,637 psi | 87% | 3064 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 55,825 psi | 86% | 3061 fps | 98.8% |
| Lovex S070 | <<locked>> | 98% | 57,145 psi | 88% | 3104 fps | 98.2% |
| Norma 201 | <<locked>> | 88% | 58,349 psi | 90% | 3081 fps | 100% |
| Norma 202 | <<locked>> | 86% | 55,521 psi | 85% | 3028 fps | 100% |
| Norma 203B | <<locked>> | 90% | 57,392 psi | 88% | 3120 fps | 100% |
| Norma 204 | <<locked>> | 98% | 56,101 psi | 86% | 3120 fps | 96.1% |
| Norma URP | <<locked>> | 98% | 55,332 psi | 85% | 3127 fps | 99.5% |
| Ramshot Big Game | <<locked>> | 90% | 58,262 psi | 90% | 3146 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 57,928 psi | 89% | 3182 fps | 98.9% |
| Ramshot TAC | <<locked>> | 84% | 55,434 psi | 85% | 3051 fps | 98.9% |
| Ramshot Wild Boar | <<locked>> | 84% | 55,158 psi | 85% | 3071 fps | 99.9% |
| Ramshot X-Terminator | <<locked>> | 82% | 56,057 psi | 86% | 3035 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,940 psi | 55% | 1949 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 58,160 psi | 89% | 3064 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 55,927 psi | 86% | 3064 fps | 98.3% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 55,027 psi | 85% | 3146 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 54,824 psi | 84% | 3182 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 56,347 psi | 87% | 3163 fps | 99.5% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 55,680 psi | 86% | 3196 fps | 99.4% |
| Rottweil R 901 | <<locked>> | 84% | 55,535 psi | 85% | 3009 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 55,187 psi | 85% | 3022 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 58,247 psi | 90% | 3117 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 58,088 psi | 89% | 3094 fps | 97.6% |
| Shooters World Long Rifle | <<locked>> | 96% | 55,825 psi | 86% | 3061 fps | 98.8% |
| Shooters World Match Rifle | <<locked>> | 86% | 56,028 psi | 86% | 3058 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 56,637 psi | 87% | 3064 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 57,145 psi | 88% | 3104 fps | 98.2% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 56,492 psi | 87% | 3127 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 57,624 psi | 89% | 3087 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 58,392 psi | 90% | 3110 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 56,260 psi | 87% | 2966 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 56,652 psi | 87% | 2959 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 56,202 psi | 86% | 3012 fps | 97.8% |
| Somchem S321 | <<locked>> | 82% | 56,449 psi | 87% | 3068 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 55,622 psi | 86% | 2959 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 57,392 psi | 88% | 3077 fps | 100% |
| Somchem S355 | <<locked>> | 94% | 58,465 psi | 90% | 3117 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 53,432 psi | 82% | 3127 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 49,429 psi | 76% | 2995 fps | 95.9% |
| Vihtavuori N130 | <<locked>> | 82% | 55,869 psi | 86% | 2923 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 56,623 psi | 87% | 2949 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 55,114 psi | 85% | 2986 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 56,231 psi | 87% | 3009 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 56,420 psi | 87% | 3038 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 57,856 psi | 89% | 3127 fps | 99.7% |
| Vihtavuori N530 | <<locked>> | 84% | 55,695 psi | 86% | 3035 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 58,044 psi | 89% | 3054 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 56,826 psi | 87% | 3127 fps | 99.5% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 45,469 psi | 70% | 2995 fps | 98.8% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 58,552 psi | 90% | 3104 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 55,840 psi | 86% | 3084 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 55,709 psi | 86% | 3140 fps | 97.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 36,651 psi | 56% | 2910 fps | 98.8% |
| Winchester StaBALL Match | <<locked>> | 88% | 58,682 psi | 90% | 3120 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% | 50,154 psi | 77% | 2881 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 42,380 psi | 65% | 2789 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 50,154 psi | 77% | 2956 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 47,979 psi | 74% | 2877 fps | 95.3% |
| Accurate 3100 | <<locked>> | 98% | 40,030 psi | 62% | 2815 fps | 95.1% |
| Accurate 4064 | <<locked>> | 80% | 40,118 psi | 62% | 2779 fps | 100% |
| Accurate 4350 | <<locked>> | 86% | 36,622 psi | 56% | 2762 fps | 95.9% |
| ADI AR 2206H | <<locked>> | 80% | 46,383 psi | 71% | 2913 fps | 99.2% |
| ADI AR 2208 | <<locked>> | 80% | 39,450 psi | 61% | 2749 fps | 97.3% |
| ADI Benchmark 8208 | <<locked>> | 80% | 48,515 psi | 75% | 2923 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 80% | 49,139 psi | 76% | 2907 fps | 100% |
| Alliant Power Pro 2000-MR | 51.9 gr | 80% | 42,525 psi | 65% | 2949 fps | 98% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 39,059 psi | 60% | 2772 fps | 98.6% |
| Alliant Reloder-15 | <<locked>> | 80% | 41,974 psi | 65% | 2841 fps | 98.1% |
| Alliant Reloder-16 | <<locked>> | 84% | 34,418 psi | 53% | 2720 fps | 95% |
| Alliant Reloder-17 | 51.1 gr | 80% | 33,837 psi | 52% | 2733 fps | 96.8% |
| Alliant Reloder-23 | <<locked>> | 92% | 31,749 psi | 49% | 2667 fps | 95.7% |
| Alliant Reloder-26 | <<locked>> | 94% | 37,202 psi | 57% | 2871 fps | 95.4% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 45,861 psi | 71% | 2917 fps | 98.4% |
| Bofors RP3 | <<locked>> | 80% | 38,667 psi | 59% | 2769 fps | 98.6% |
| Bofors RP7 | <<locked>> | 90% | 48,211 psi | 74% | 2923 fps | 95.6% |
| Hodgdon Benchmark | <<locked>> | 80% | 49,995 psi | 77% | 2910 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 47,674 psi | 73% | 2943 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 53,040 psi | 82% | 3107 fps | 99.7% |
| Hodgdon H380 | <<locked>> | 80% | 39,465 psi | 61% | 2776 fps | 96.2% |
| Hodgdon H414 | <<locked>> | 90% | 45,266 psi | 70% | 2949 fps | 95.6% |
| Hodgdon H4350 | <<locked>> | 90% | 49,255 psi | 76% | 2979 fps | 95.1% |
| Hodgdon H4895 | <<locked>> | 80% | 46,833 psi | 72% | 2927 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 31,444 psi | 48% | 2608 fps | 95.8% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 43,091 psi | 66% | 2894 fps | 99.4% |
| Hodgdon Superformance | <<locked>> | 92% | 48,675 psi | 75% | 3038 fps | 96% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,353 psi | 41% | 1703 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 44,875 psi | 69% | 2871 fps | 99.3% |
| IMR 3031 | <<locked>> | 80% | 46,557 psi | 72% | 2917 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 41,394 psi | 64% | 2789 fps | 98% |
| IMR 4166 Enduron | <<locked>> | 80% | 43,918 psi | 68% | 2812 fps | 95.1% |
| IMR 4350 | <<locked>> | 94% | 48,617 psi | 75% | 2949 fps | 95.8% |
| IMR 4451 Enduron | <<locked>> | 86% | 44,048 psi | 68% | 2841 fps | 95% |
| IMR 4831 | <<locked>> | 86% | 35,520 psi | 55% | 2720 fps | 95.6% |
| IMR 4895 | <<locked>> | 80% | 43,033 psi | 66% | 2874 fps | 98.8% |
| IMR 8208 XBR | <<locked>> | 80% | 48,515 psi | 75% | 2923 fps | 99.9% |
| Lovex D073.6 | <<locked>> | 80% | 45,730 psi | 70% | 2890 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 46,282 psi | 71% | 2848 fps | 99.2% |
| Lovex S062 | <<locked>> | 80% | 41,278 psi | 64% | 2789 fps | 99.3% |
| Lovex S065 | <<locked>> | 86% | 40,886 psi | 63% | 2779 fps | 95.7% |
| Lovex S070 | <<locked>> | 90% | 44,222 psi | 68% | 2871 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 45,136 psi | 69% | 2858 fps | 99.7% |
| Norma 202 | <<locked>> | 80% | 45,730 psi | 70% | 2871 fps | 100% |
| Norma 203B | <<locked>> | 80% | 41,365 psi | 64% | 2828 fps | 98.4% |
| Norma 204 | <<locked>> | 96% | 52,199 psi | 80% | 3051 fps | 95.2% |
| Norma URP | <<locked>> | 86% | 37,072 psi | 57% | 2769 fps | 95.9% |
| Ramshot Big Game | <<locked>> | 80% | 41,249 psi | 63% | 2844 fps | 98.2% |
| Ramshot Hunter | <<locked>> | 90% | 41,452 psi | 64% | 2874 fps | 95.4% |
| Ramshot TAC | <<locked>> | 80% | 48,501 psi | 75% | 2930 fps | 97.8% |
| Ramshot Wild Boar | <<locked>> | 80% | 48,138 psi | 74% | 2949 fps | 99.4% |
| Ramshot X-Terminator | <<locked>> | 80% | 52,475 psi | 81% | 2976 fps | 99.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,643 psi | 41% | 1742 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 54,288 psi | 84% | 3009 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 42,743 psi | 66% | 2822 fps | 95.4% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 44,657 psi | 69% | 2956 fps | 98.6% |
| ReloadSwiss RS 60 | 51.1 gr | 80% | 36,056 psi | 55% | 2808 fps | 99.5% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 36,506 psi | 56% | 2782 fps | 95.4% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 39,088 psi | 60% | 2854 fps | 95.6% |
| Rottweil R 901 | <<locked>> | 80% | 48,892 psi | 75% | 2900 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,859 psi | 66% | 2805 fps | 99.5% |
| Rottweil R 903 | <<locked>> | 80% | 36,434 psi | 56% | 2713 fps | 97.8% |
| Rottweil R 907 | <<locked>> | 90% | 48,211 psi | 74% | 2923 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 86% | 40,886 psi | 63% | 2779 fps | 95.7% |
| Shooters World Match Rifle | <<locked>> | 80% | 45,730 psi | 70% | 2890 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 41,278 psi | 64% | 2789 fps | 99.3% |
| Shooters World SW4350 | <<locked>> | 90% | 44,222 psi | 68% | 2871 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 37,608 psi | 58% | 2769 fps | 97.4% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 46,717 psi | 72% | 2900 fps | 97.9% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 44,947 psi | 69% | 2881 fps | 99% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 46,470 psi | 71% | 2812 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,725 psi | 60% | 2664 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 46,151 psi | 71% | 2841 fps | 95.8% |
| Somchem S321 | <<locked>> | 80% | 52,736 psi | 81% | 3009 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 46,093 psi | 71% | 2808 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 46,688 psi | 72% | 2897 fps | 99.2% |
| Somchem S355 | <<locked>> | 80% | 37,086 psi | 57% | 2717 fps | 97.8% |
| Somchem S365 | <<locked>> | 80% | 26,890 psi | 41% | 2523 fps | 95% |
| Somchem S385 | <<locked>> | 98% | 46,296 psi | 71% | 2936 fps | 95.1% |
| Vihtavuori N130 | <<locked>> | 80% | 52,417 psi | 81% | 2874 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 46,905 psi | 72% | 2802 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 42,583 psi | 66% | 2789 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 43,424 psi | 67% | 2802 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 35,476 psi | 55% | 2654 fps | 98.6% |
| Vihtavuori N160 | <<locked>> | 84% | 36,085 psi | 56% | 2710 fps | 95.4% |
| Vihtavuori N530 | <<locked>> | 80% | 48,631 psi | 75% | 2917 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 80% | 41,640 psi | 64% | 2782 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 35,491 psi | 55% | 2707 fps | 95% |
| Vihtavuori N555 | <<locked>> | 92% | 34,461 psi | 53% | 2749 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 31,386 psi | 48% | 2569 fps | 96% |
| Winchester 748 | <<locked>> | 80% | 48,762 psi | 75% | 2969 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 45,542 psi | 70% | 2956 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 94% | 30,023 psi | 46% | 2690 fps | 95.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 44,440 psi | 68% | 2881 fps | 99.3% |
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 115 powders for .280 Ackley Improved loaded with the .284 | 127gr | Geco ZERO. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,212 fps; across all powders the maximum-charge window runs from 1,903 fps to 3,212 fps. Accurate 3100 gives the best case fill at 100 %, and 115 of the 115 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 54–90 %, 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, ADI AR 2209, Alliant Reloder-16 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. Alliant Power Pro 2000-MR, Alliant Reloder-17, ReloadSwiss RS 60 rank at the top here: for .280 Ackley Improved with the .284 | 127gr | Geco ZERO they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2209, Alliant Reloder-19, Alliant Reloder-22 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.