Load Specifications
Bullet:.284 | 139gr | Hornady GMX
Bullet Manufacturer:Hornady
Bullet Weight:139 gr
Bullet Diameter:0.284"
Bullet Length:<<locked>>
Caliber:.280 Ackley Improved load data
Case Length (l3):2.54"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:74 Grains of Water
Primer Size:Large Rifle (LR)
Barrel Length:24"
Max. allowed Pressure:65,000 psi
Recommended Twist Rate:1:10.5
Load data in caliber .280 Ackley Improved with .284 | 139gr | Hornady GMX bullet and 104 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 70, Hodgdon Superformance and Alliant Reloder-17.
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>> | 82% | 56,144 psi | 86% | 2838 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 55,143 psi | 85% | 2861 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 57,000 psi | 88% | 2933 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 58,073 psi | 89% | 2936 fps | 98.2% |
| Accurate 3100ᴾ | <<locked>> | 100% | 46,499 psi | 72% | 2835 fps | 97.8% |
| Accurate 4064 | <<locked>> | 88% | 55,521 psi | 85% | 2917 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 56,391 psi | 87% | 3018 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 84% | 55,738 psi | 86% | 2953 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 56,898 psi | 88% | 2956 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 54,389 psi | 84% | 2999 fps | 96.9% |
| ADI Benchmark 8208 | <<locked>> | 84% | 58,146 psi | 89% | 2953 fps | 100% |
| Alliant AR-Comp | <<locked>> | 82% | 56,014 psi | 86% | 2871 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 55,811 psi | 86% | 3081 fps | 100% |
| Alliant Power Pro Varmintᴾ | <<locked>> | 100% | 54,114 psi | 83% | 2992 fps | 96.9% |
| Alliant Power Pro Varmintᴾ | <<locked>> | 100% | 54,114 psi | 83% | 2992 fps | 96.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 57,232 psi | 88% | 2979 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 57,725 psi | 89% | 3002 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 98% | 57,508 psi | 88% | 3081 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 92% | 55,071 psi | 85% | 3054 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 53,316 psi | 82% | 2982 fps | 96.8% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 44,005 psi | 68% | 2861 fps | 99.8% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 38,609 psi | 59% | 2759 fps | 96.3% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 50,067 psi | 77% | 3048 fps | 99.6% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 55,651 psi | 86% | 2969 fps | 99.9% |
| Bofors RP3 | <<locked>> | 90% | 58,117 psi | 89% | 2995 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 57,580 psi | 89% | 2969 fps | 98.4% |
| Hodgdon Benchmark | <<locked>> | 82% | 55,854 psi | 86% | 2877 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 58,015 psi | 89% | 2982 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 54,940 psi | 85% | 2953 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 94% | 55,463 psi | 85% | 3018 fps | 98.6% |
| Hodgdon H4350 | <<locked>> | 92% | 55,651 psi | 86% | 2976 fps | 97.5% |
| Hodgdon H4895 | <<locked>> | 84% | 56,333 psi | 87% | 2963 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 57,406 psi | 88% | 2995 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 56,362 psi | 87% | 2999 fps | 100% |
| Hodgdon Superformance | <<locked>> | 94% | 55,738 psi | 86% | 3054 fps | 98.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,824 psi | 55% | 1824 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 57,508 psi | 88% | 2966 fps | 100% |
| IMR 3031 | <<locked>> | 84% | 56,768 psi | 87% | 2943 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 56,202 psi | 86% | 2936 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 86% | 55,927 psi | 86% | 2920 fps | 98.5% |
| IMR 4350 | <<locked>> | 98% | 58,581 psi | 90% | 3005 fps | 98.5% |
| IMR 4451 Enduron | <<locked>> | 92% | 56,014 psi | 86% | 2946 fps | 98.5% |
| IMR 4831 | <<locked>> | 98% | 56,797 psi | 87% | 3005 fps | 99.9% |
| IMR 4895 | <<locked>> | 86% | 55,564 psi | 85% | 2976 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 58,146 psi | 89% | 2953 fps | 100% |
| Lovex D073.6 | <<locked>> | 84% | 55,637 psi | 86% | 2923 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 58,392 psi | 90% | 2930 fps | 100% |
| Lovex S062 | <<locked>> | 88% | 56,043 psi | 86% | 2930 fps | 100% |
| Lovex S065 | <<locked>> | 94% | 55,709 psi | 86% | 2943 fps | 99.4% |
| Lovex S070 | <<locked>> | 96% | 56,898 psi | 88% | 2982 fps | 98.9% |
| Norma 201 | <<locked>> | 86% | 57,566 psi | 89% | 2943 fps | 100% |
| Norma 202 | <<locked>> | 86% | 58,436 psi | 90% | 2943 fps | 100% |
| Norma 203B | <<locked>> | 88% | 56,913 psi | 88% | 2986 fps | 100% |
| Norma 204 | <<locked>> | 96% | 55,738 psi | 86% | 2999 fps | 97% |
| Norma MRPᴾ | <<locked>> | 100% | 49,501 psi | 76% | 2999 fps | 97.6% |
| Norma URP | <<locked>> | 96% | 55,332 psi | 85% | 3005 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 88% | 57,798 psi | 89% | 3012 fps | 100% |
| Ramshot Hunter | <<locked>> | 98% | 57,812 psi | 89% | 3058 fps | 99.4% |
| Ramshot TAC | <<locked>> | 84% | 58,320 psi | 90% | 2976 fps | 99.6% |
| Ramshot Wild Boar | <<locked>> | 84% | 58,218 psi | 90% | 2992 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 58,813 psi | 90% | 2953 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,376 psi | 56% | 1867 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 55,216 psi | 85% | 2936 fps | 98.9% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 54,781 psi | 84% | 3015 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 58,682 psi | 90% | 3107 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 56,434 psi | 87% | 3041 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 55,463 psi | 85% | 3074 fps | 99.8% |
| Rottweil R 901 | <<locked>> | 84% | 58,175 psi | 89% | 2917 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 58,392 psi | 90% | 2946 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 57,986 psi | 89% | 2986 fps | 100% |
| Rottweil R 904ᴾ | <<locked>> | 100% | 56,014 psi | 86% | 2966 fps | 96% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 52,141 psi | 80% | 2963 fps | 96.7% |
| Rottweil R 907 | <<locked>> | 94% | 57,580 psi | 89% | 2969 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 94% | 55,709 psi | 86% | 2943 fps | 99.4% |
| Shooters World Match Rifle | <<locked>> | 84% | 55,637 psi | 86% | 2923 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 56,043 psi | 86% | 2930 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 56,898 psi | 88% | 2982 fps | 98.9% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 56,028 psi | 86% | 2995 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 56,811 psi | 87% | 2953 fps | 99.7% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 57,885 psi | 89% | 2979 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 55,434 psi | 85% | 2828 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 56,086 psi | 86% | 2828 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 55,651 psi | 86% | 2894 fps | 98.5% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 51,648 psi | 79% | 2959 fps | 96.6% |
| Somchem S335 | <<locked>> | 86% | 58,291 psi | 90% | 2871 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 56,637 psi | 87% | 2943 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 58,044 psi | 89% | 2982 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 57,798 psi | 89% | 3061 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 53,055 psi | 82% | 2946 fps | 97.7% |
| Vihtavuori N130 | <<locked>> | 82% | 58,581 psi | 90% | 2831 fps | 100% |
| Vihtavuori N133 | <<locked>> | 84% | 55,912 psi | 86% | 2812 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 58,523 psi | 90% | 2904 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 55,535 psi | 85% | 2871 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 55,985 psi | 86% | 2907 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 57,769 psi | 89% | 3002 fps | 99.9% |
| Vihtavuori N530 | <<locked>> | 84% | 58,581 psi | 90% | 2949 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 57,246 psi | 88% | 2917 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 56,536 psi | 87% | 3002 fps | 99.8% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 48,950 psi | 75% | 2940 fps | 99.7% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 57,943 psi | 89% | 2972 fps | 100% |
| Winchester 748 | <<locked>> | 82% | 55,419 psi | 85% | 2946 fps | 100% |
| Winchester 760 | <<locked>> | 94% | 55,463 psi | 85% | 3018 fps | 98.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 39,523 psi | 61% | 2890 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 86% | 57,943 psi | 89% | 2986 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% | 52,881 psi | 81% | 2792 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 45,237 psi | 70% | 2713 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 53,388 psi | 82% | 2884 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 44,469 psi | 68% | 2703 fps | 95.4% |
| Accurate 3100 | <<locked>> | 94% | 37,652 psi | 58% | 2657 fps | 95.4% |
| Accurate 4064 | <<locked>> | 80% | 42,815 psi | 66% | 2713 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 31,981 psi | 49% | 2539 fps | 95.1% |
| ADI AR 2206H | <<locked>> | 80% | 49,023 psi | 75% | 2844 fps | 99.8% |
| ADI AR 2208 | <<locked>> | 80% | 41,437 psi | 64% | 2684 fps | 98.6% |
| ADI AR 2209 | <<locked>> | 96% | 47,630 psi | 73% | 2877 fps | 95.2% |
| ADI Benchmark 8208 | <<locked>> | 80% | 51,198 psi | 79% | 2848 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 52,272 psi | 80% | 2822 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 45,165 psi | 69% | 2890 fps | 99.3% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 47,442 psi | 73% | 2874 fps | 95.3% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 47,442 psi | 73% | 2874 fps | 95.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 41,539 psi | 64% | 2710 fps | 99.6% |
| Alliant Reloder-15 | <<locked>> | 80% | 44,570 psi | 69% | 2779 fps | 99.2% |
| Alliant Reloder-16 | <<locked>> | 80% | 32,097 psi | 49% | 2556 fps | 95.3% |
| Alliant Reloder-17 | 50.5 gr | 80% | 36,013 psi | 55% | 2687 fps | 98.5% |
| Alliant Reloder-19 | <<locked>> | 96% | 46,818 psi | 72% | 2867 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 88% | 29,776 psi | 46% | 2516 fps | 96% |
| Alliant Reloder-25 | <<locked>> | 98% | 36,172 psi | 56% | 2697 fps | 95.2% |
| Alliant Reloder-26 | <<locked>> | 90% | 34,548 psi | 53% | 2703 fps | 95.6% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 48,530 psi | 75% | 2851 fps | 99.4% |
| Bofors RP3 | <<locked>> | 80% | 41,321 psi | 64% | 2713 fps | 99.6% |
| Bofors RP7 | <<locked>> | 86% | 44,701 psi | 69% | 2743 fps | 95.7% |
| Hodgdon Benchmark | <<locked>> | 80% | 52,475 psi | 81% | 2828 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 50,488 psi | 78% | 2871 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 42,018 psi | 65% | 2720 fps | 97.8% |
| Hodgdon H414 | <<locked>> | 86% | 42,134 psi | 65% | 2772 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 86% | 45,629 psi | 70% | 2799 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 49,530 psi | 76% | 2854 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 29,515 psi | 45% | 2451 fps | 96.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 45,818 psi | 70% | 2828 fps | 99.9% |
| Hodgdon Superformance | 57.4 gr | 86% | 41,597 psi | 64% | 2785 fps | 95% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,571 psi | 41% | 1627 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 47,398 psi | 73% | 2802 fps | 99.9% |
| IMR 3031 | <<locked>> | 80% | 49,545 psi | 76% | 2838 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 43,555 psi | 67% | 2720 fps | 99.1% |
| IMR 4166 Enduron | <<locked>> | 80% | 46,021 psi | 71% | 2746 fps | 96.7% |
| IMR 4350 | <<locked>> | 88% | 42,569 psi | 65% | 2720 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 82% | 41,031 psi | 63% | 2671 fps | 95.2% |
| IMR 4831 | <<locked>> | 82% | 33,170 psi | 51% | 2552 fps | 95.8% |
| IMR 4895 | <<locked>> | 80% | 45,701 psi | 70% | 2812 fps | 99.6% |
| IMR 8208 XBR | <<locked>> | 80% | 51,198 psi | 79% | 2848 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 48,486 psi | 75% | 2815 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 48,341 psi | 74% | 2769 fps | 99.8% |
| Lovex S062 | <<locked>> | 80% | 43,482 psi | 67% | 2720 fps | 99.9% |
| Lovex S065 | <<locked>> | 80% | 35,737 psi | 55% | 2556 fps | 95% |
| Lovex S070 | <<locked>> | 86% | 41,234 psi | 63% | 2697 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 47,659 psi | 73% | 2785 fps | 100% |
| Norma 202 | <<locked>> | 80% | 48,414 psi | 74% | 2792 fps | 100% |
| Norma 203B | <<locked>> | 80% | 43,932 psi | 68% | 2766 fps | 99.4% |
| Norma 204 | <<locked>> | 92% | 48,472 psi | 75% | 2874 fps | 95.4% |
| Norma MRP | <<locked>> | 96% | 43,018 psi | 66% | 2867 fps | 95.8% |
| Norma URP | <<locked>> | 80% | 32,213 psi | 50% | 2539 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 80% | 43,874 psi | 67% | 2782 fps | 99.3% |
| Ramshot Hunter | <<locked>> | 86% | 38,624 psi | 59% | 2703 fps | 95.6% |
| Ramshot TAC | <<locked>> | 80% | 50,995 psi | 78% | 2861 fps | 98.9% |
| Ramshot Wild Boar | <<locked>> | 80% | 51,068 psi | 79% | 2881 fps | 99.9% |
| Ramshot X-Terminator | <<locked>> | 80% | 55,013 psi | 85% | 2897 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,919 psi | 41% | 1667 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 42,337 psi | 65% | 2703 fps | 96.4% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 47,558 psi | 73% | 2894 fps | 99.5% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 38,377 psi | 59% | 2753 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 34,084 psi | 52% | 2615 fps | 95.6% |
| ReloadSwiss RS 70 | 53.9 gr | 84% | 36,361 psi | 56% | 2687 fps | 95.8% |
| Rottweil R 901 | <<locked>> | 80% | 51,474 psi | 79% | 2818 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 45,310 psi | 70% | 2736 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 80% | 38,754 psi | 60% | 2654 fps | 99.1% |
| Rottweil R 904 | <<locked>> | 98% | 52,707 psi | 81% | 2913 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 96% | 45,455 psi | 70% | 2844 fps | 95% |
| Rottweil R 907 | <<locked>> | 86% | 44,701 psi | 69% | 2743 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 35,737 psi | 55% | 2556 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 48,486 psi | 75% | 2815 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 43,482 psi | 67% | 2720 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 86% | 41,234 psi | 63% | 2697 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 39,987 psi | 62% | 2710 fps | 98.7% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 49,632 psi | 76% | 2838 fps | 99.1% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 47,384 psi | 73% | 2808 fps | 99.7% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 48,834 psi | 75% | 2730 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 40,886 psi | 63% | 2592 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 40,030 psi | 62% | 2612 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 48,196 psi | 74% | 2897 fps | 95.8% |
| Somchem S335 | <<locked>> | 80% | 48,530 psi | 75% | 2730 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 49,342 psi | 76% | 2828 fps | 99.8% |
| Somchem S355 | <<locked>> | 80% | 39,465 psi | 61% | 2661 fps | 99% |
| Somchem S365 | <<locked>> | 80% | 28,863 psi | 44% | 2490 fps | 97.4% |
| Somchem S385 | <<locked>> | 94% | 43,236 psi | 67% | 2769 fps | 95.3% |
| Vihtavuori N130 | <<locked>> | 80% | 54,955 psi | 85% | 2785 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 49,356 psi | 76% | 2720 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 45,223 psi | 70% | 2710 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 45,730 psi | 70% | 2723 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 37,565 psi | 58% | 2592 fps | 99.5% |
| Vihtavuori N160 | <<locked>> | 80% | 33,765 psi | 52% | 2549 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 51,372 psi | 79% | 2844 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 44,164 psi | 68% | 2713 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 33,156 psi | 51% | 2543 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 86% | 30,429 psi | 47% | 2536 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 33,214 psi | 51% | 2520 fps | 97.8% |
| Winchester 748 | <<locked>> | 80% | 51,605 psi | 79% | 2890 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 42,351 psi | 65% | 2776 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 90% | 28,036 psi | 43% | 2536 fps | 95.6% |
| Winchester StaBALL Match | <<locked>> | 80% | 47,282 psi | 73% | 2818 fps | 99.9% |
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 104 powders for .280 Ackley Improved loaded with the .284 | 139gr | Hornady GMX. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,107 fps; across all powders the maximum-charge window runs from 1,824 fps to 3,107 fps. Accurate 3100 gives the best case fill at 100 %, and 104 of the 104 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 139.0 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 Power Pro Varmint 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, Hodgdon Superformance, Alliant Reloder-17 rank at the top here: for .280 Ackley Improved with the .284 | 139gr | Hornady GMX 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.