Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 135gr | Atomic 29 HP bullet and 101 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-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.
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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>> | 82% | 57,276 psi | 88% | 2890 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 56,666 psi | 87% | 2920 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 56,652 psi | 87% | 2976 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 56,652 psi | 87% | 2976 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 56,275 psi | 87% | 2933 fps | 97.8% |
| Accurate 3100ᴾ | <<locked>> | 100% | 47,601 psi | 73% | 2884 fps | 97.8% |
| Accurate 4064 | <<locked>> | 88% | 56,869 psi | 87% | 2972 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 57,537 psi | 89% | 3071 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 84% | 56,521 psi | 87% | 3005 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 57,522 psi | 88% | 3005 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 55,027 psi | 85% | 3045 fps | 96.7% |
| ADI Benchmark 8208 | <<locked>> | 82% | 55,114 psi | 85% | 2946 fps | 100% |
| Alliant AR-Comp | <<locked>> | 82% | 56,695 psi | 87% | 2920 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 56,652 psi | 87% | 3130 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 57,957 psi | 89% | 3025 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 58,465 psi | 90% | 3051 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 98% | 58,233 psi | 90% | 3130 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 92% | 55,854 psi | 86% | 3104 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 53,983 psi | 83% | 3031 fps | 96.7% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 44,860 psi | 69% | 2910 fps | 99.8% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 39,407 psi | 61% | 2805 fps | 96.3% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 51,039 psi | 79% | 3100 fps | 99.6% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 56,507 psi | 87% | 3018 fps | 99.9% |
| Bofors RP3 | <<locked>> | 88% | 55,376 psi | 85% | 2992 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 58,479 psi | 90% | 3018 fps | 98.3% |
| Hodgdon Benchmark | <<locked>> | 82% | 56,652 psi | 87% | 2930 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 58,755 psi | 90% | 3031 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 56,072 psi | 86% | 3009 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 92% | 57,754 psi | 89% | 3091 fps | 98.7% |
| Hodgdon H4350 | <<locked>> | 96% | 57,914 psi | 89% | 3048 fps | 97.7% |
| Hodgdon H4895 | <<locked>> | 84% | 57,174 psi | 88% | 3015 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 58,537 psi | 90% | 3048 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 57,305 psi | 88% | 3051 fps | 100% |
| Hodgdon Superformance | <<locked>> | 94% | 56,565 psi | 87% | 3100 fps | 98.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,955 psi | 55% | 1857 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 57,290 psi | 88% | 3002 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 56,188 psi | 86% | 2972 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 56,347 psi | 87% | 2976 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 90% | 55,419 psi | 85% | 2949 fps | 98.3% |
| IMR 4350 | <<locked>> | 96% | 55,680 psi | 86% | 2995 fps | 97.9% |
| IMR 4451 Enduron | <<locked>> | 92% | 56,811 psi | 87% | 2999 fps | 98.4% |
| IMR 4831ᴾ | <<locked>> | 100% | 54,984 psi | 85% | 3015 fps | 99.8% |
| IMR 4895 | <<locked>> | 86% | 56,362 psi | 87% | 3028 fps | 100% |
| IMR 8208 XBR | <<locked>> | 82% | 55,114 psi | 85% | 2946 fps | 100% |
| Lovex D073.6 | <<locked>> | 84% | 56,652 psi | 87% | 2976 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 55,593 psi | 86% | 2927 fps | 100% |
| Lovex S062 | <<locked>> | 88% | 56,956 psi | 88% | 2979 fps | 100% |
| Lovex S065 | <<locked>> | 94% | 56,434 psi | 87% | 2989 fps | 99.3% |
| Lovex S070 | <<locked>> | 96% | 57,841 psi | 89% | 3031 fps | 98.8% |
| Norma 201 | <<locked>> | 86% | 58,566 psi | 90% | 2995 fps | 100% |
| Norma 202 | <<locked>> | 84% | 55,709 psi | 86% | 2943 fps | 100% |
| Norma 203B | <<locked>> | 88% | 57,711 psi | 89% | 3038 fps | 100% |
| Norma 204 | <<locked>> | 96% | 56,405 psi | 87% | 3045 fps | 96.9% |
| Norma MRPᴾ | <<locked>> | 100% | 50,430 psi | 78% | 3051 fps | 97.5% |
| Norma URP | <<locked>> | 96% | 56,246 psi | 87% | 3054 fps | 99.8% |
| Ramshot Big Game | <<locked>> | 88% | 58,653 psi | 90% | 3064 fps | 100% |
| Ramshot Hunter | <<locked>> | 98% | 58,798 psi | 90% | 3110 fps | 99.4% |
| Ramshot TAC | <<locked>> | 82% | 55,477 psi | 85% | 2972 fps | 99.3% |
| Ramshot Wild Boar | <<locked>> | 82% | 55,390 psi | 85% | 2989 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,550 psi | 56% | 1900 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 56,144 psi | 86% | 2989 fps | 98.9% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 55,564 psi | 85% | 3064 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 55,419 psi | 85% | 3100 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 57,232 psi | 88% | 3094 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 56,086 psi | 86% | 3120 fps | 99.8% |
| Rottweil R 901 | <<locked>> | 82% | 55,912 psi | 86% | 2923 fps | 100% |
| Rottweil R 902 | <<locked>> | 86% | 55,767 psi | 86% | 2943 fps | 100% |
| Rottweil R 903 | <<locked>> | 90% | 55,187 psi | 85% | 2986 fps | 100% |
| Rottweil R 904ᴾ | <<locked>> | 100% | 56,971 psi | 88% | 3022 fps | 96% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 53,171 psi | 82% | 3018 fps | 96.7% |
| Rottweil R 907 | <<locked>> | 94% | 58,479 psi | 90% | 3018 fps | 98.3% |
| Shooters World Long Rifle | <<locked>> | 94% | 56,434 psi | 87% | 2989 fps | 99.3% |
| Shooters World Match Rifle | <<locked>> | 84% | 56,652 psi | 87% | 2976 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 56,956 psi | 88% | 2979 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 57,841 psi | 89% | 3031 fps | 98.8% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 56,913 psi | 88% | 3045 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 57,914 psi | 89% | 3009 fps | 99.7% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 58,523 psi | 90% | 3025 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 56,347 psi | 87% | 2881 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 56,753 psi | 87% | 2877 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 56,565 psi | 87% | 2943 fps | 98.5% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 52,678 psi | 81% | 3012 fps | 96.5% |
| Somchem S335 | <<locked>> | 84% | 55,695 psi | 86% | 2874 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 57,580 psi | 89% | 2995 fps | 100% |
| Somchem S355 | <<locked>> | 90% | 55,274 psi | 85% | 2979 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 58,566 psi | 90% | 3107 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 53,882 psi | 83% | 2995 fps | 97.6% |
| Unknown powder | <<locked>> | 94% | 57,029 psi | 88% | 3061 fps | 99.7% |
| Vihtavuori N133 | <<locked>> | 84% | 56,739 psi | 87% | 2861 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 55,753 psi | 86% | 2904 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 56,347 psi | 87% | 2920 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 56,681 psi | 87% | 2956 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 58,566 psi | 90% | 3051 fps | 99.9% |
| Vihtavuori N530 | <<locked>> | 82% | 55,724 psi | 86% | 2946 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 58,189 psi | 90% | 2966 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 57,653 psi | 89% | 3058 fps | 99.8% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 49,966 psi | 77% | 2992 fps | 99.7% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 58,784 psi | 90% | 3022 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 57,754 psi | 89% | 3091 fps | 98.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 40,335 psi | 62% | 2940 fps | 99.9% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 56,434 psi | 87% | 3022 fps | 97% |
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% | 53,751 psi | 83% | 2844 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 46,862 psi | 72% | 2776 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 52,881 psi | 81% | 2920 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 52,881 psi | 81% | 2920 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 46,296 psi | 71% | 2762 fps | 95.7% |
| Accurate 3100 | <<locked>> | 94% | 38,841 psi | 60% | 2713 fps | 95.5% |
| Accurate 4064 | <<locked>> | 80% | 44,353 psi | 68% | 2772 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 33,011 psi | 51% | 2592 fps | 95.3% |
| ADI AR 2206H | <<locked>> | 80% | 49,705 psi | 76% | 2890 fps | 99.8% |
| ADI AR 2208 | <<locked>> | 80% | 42,293 psi | 65% | 2733 fps | 98.6% |
| ADI AR 2209 | <<locked>> | 96% | 48,370 psi | 74% | 2927 fps | 95.1% |
| ADI Benchmark 8208 | <<locked>> | 80% | 51,779 psi | 80% | 2894 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 53,055 psi | 82% | 2871 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 45,890 psi | 71% | 2940 fps | 99.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 42,337 psi | 65% | 2759 fps | 99.5% |
| Alliant Reloder-15 | <<locked>> | 80% | 45,324 psi | 70% | 2828 fps | 99.2% |
| Alliant Reloder-16 | <<locked>> | 80% | 32,822 psi | 50% | 2602 fps | 95.3% |
| Alliant Reloder-17 | 51.3 gr | 80% | 36,854 psi | 57% | 2740 fps | 98.5% |
| Alliant Reloder-19 | <<locked>> | 96% | 47,587 psi | 73% | 2917 fps | 95.1% |
| Alliant Reloder-23 | <<locked>> | 86% | 28,790 psi | 44% | 2510 fps | 95.1% |
| Alliant Reloder-25 | <<locked>> | 98% | 37,057 psi | 57% | 2746 fps | 95.2% |
| Alliant Reloder-26 | <<locked>> | 90% | 35,723 psi | 55% | 2762 fps | 95.7% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 49,226 psi | 76% | 2900 fps | 99.4% |
| Bofors RP3 | <<locked>> | 80% | 42,264 psi | 65% | 2766 fps | 99.6% |
| Bofors RP7 | <<locked>> | 86% | 45,556 psi | 70% | 2792 fps | 95.7% |
| Hodgdon Benchmark | <<locked>> | 80% | 53,330 psi | 82% | 2877 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 51,358 psi | 79% | 2920 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 43,004 psi | 66% | 2772 fps | 97.8% |
| Hodgdon H414 | <<locked>> | 82% | 40,901 psi | 63% | 2776 fps | 95% |
| Hodgdon H4350 | <<locked>> | 90% | 48,066 psi | 74% | 2881 fps | 95.6% |
| Hodgdon H4895 | <<locked>> | 80% | 50,212 psi | 77% | 2904 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 30,298 psi | 47% | 2500 fps | 96.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 43,976 psi | 68% | 2828 fps | 99.8% |
| Hodgdon Superformance | <<locked>> | 88% | 45,716 psi | 70% | 2907 fps | 96% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,861 psi | 41% | 1660 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 44,541 psi | 69% | 2782 fps | 99.6% |
| IMR 3031 | <<locked>> | 80% | 46,282 psi | 71% | 2822 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 41,481 psi | 64% | 2710 fps | 98.6% |
| IMR 4166 Enduron | <<locked>> | 80% | 40,915 psi | 63% | 2671 fps | 95% |
| IMR 4350 | <<locked>> | 88% | 43,265 psi | 67% | 2769 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 82% | 41,597 psi | 64% | 2713 fps | 95.1% |
| IMR 4831 | <<locked>> | 84% | 33,069 psi | 51% | 2579 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 46,427 psi | 71% | 2858 fps | 99.6% |
| IMR 8208 XBR | <<locked>> | 80% | 51,779 psi | 80% | 2894 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 49,603 psi | 76% | 2867 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 49,182 psi | 76% | 2822 fps | 99.8% |
| Lovex S062 | <<locked>> | 80% | 44,556 psi | 69% | 2772 fps | 99.9% |
| Lovex S065 | <<locked>> | 80% | 36,782 psi | 57% | 2608 fps | 95.1% |
| Lovex S070 | <<locked>> | 86% | 42,192 psi | 65% | 2749 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 48,849 psi | 75% | 2841 fps | 100% |
| Norma 202 | <<locked>> | 80% | 49,139 psi | 76% | 2841 fps | 100% |
| Norma 203B | <<locked>> | 80% | 44,701 psi | 69% | 2815 fps | 99.4% |
| Norma 204 | <<locked>> | 92% | 49,269 psi | 76% | 2923 fps | 95.3% |
| Norma MRP | <<locked>> | 96% | 44,063 psi | 68% | 2923 fps | 95.8% |
| Norma URP | <<locked>> | 80% | 33,185 psi | 51% | 2595 fps | 95.2% |
| Ramshot Big Game | <<locked>> | 80% | 44,672 psi | 69% | 2831 fps | 99.3% |
| Ramshot Hunter | <<locked>> | 86% | 39,392 psi | 61% | 2753 fps | 95.5% |
| Ramshot TAC | <<locked>> | 80% | 51,721 psi | 80% | 2907 fps | 98.9% |
| Ramshot Wild Boar | <<locked>> | 80% | 51,808 psi | 80% | 2930 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,253 psi | 42% | 1699 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 43,221 psi | 66% | 2753 fps | 96.4% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 48,486 psi | 75% | 2946 fps | 99.5% |
| ReloadSwiss RS 60 | 51.3 gr | 80% | 39,189 psi | 60% | 2805 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 35,041 psi | 54% | 2667 fps | 95.7% |
| ReloadSwiss RS 70 | 54.7 gr | 84% | 37,101 psi | 57% | 2733 fps | 95.8% |
| Rottweil R 901 | <<locked>> | 80% | 52,852 psi | 81% | 2874 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 46,456 psi | 71% | 2789 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 80% | 39,900 psi | 61% | 2710 fps | 99.1% |
| Rottweil R 904 | <<locked>> | 98% | 53,447 psi | 82% | 2963 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 96% | 46,586 psi | 72% | 2897 fps | 95% |
| Rottweil R 907 | <<locked>> | 86% | 45,556 psi | 70% | 2792 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 36,782 psi | 57% | 2608 fps | 95.1% |
| Shooters World Match Rifle | <<locked>> | 80% | 49,603 psi | 76% | 2867 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 44,556 psi | 69% | 2772 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 86% | 42,192 psi | 65% | 2749 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 40,843 psi | 63% | 2759 fps | 98.7% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 50,546 psi | 78% | 2887 fps | 99.1% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 48,225 psi | 74% | 2861 fps | 99.7% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 49,821 psi | 77% | 2782 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 41,858 psi | 64% | 2641 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 40,988 psi | 63% | 2661 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 49,269 psi | 76% | 2953 fps | 95.8% |
| Somchem S335 | <<locked>> | 80% | 49,545 psi | 76% | 2782 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 50,096 psi | 77% | 2877 fps | 99.8% |
| Somchem S355 | <<locked>> | 80% | 40,524 psi | 62% | 2713 fps | 99.1% |
| Somchem S365 | <<locked>> | 80% | 29,863 psi | 46% | 2546 fps | 97.5% |
| Somchem S385 | <<locked>> | 94% | 44,237 psi | 68% | 2818 fps | 95.3% |
| Unknown powder | <<locked>> | 80% | 35,868 psi | 55% | 2654 fps | 95.5% |
| Vihtavuori N133 | <<locked>> | 80% | 50,285 psi | 77% | 2769 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 46,354 psi | 71% | 2762 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 46,688 psi | 72% | 2772 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 38,580 psi | 59% | 2644 fps | 99.5% |
| Vihtavuori N160 | <<locked>> | 80% | 34,519 psi | 53% | 2595 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 51,982 psi | 80% | 2890 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 45,049 psi | 69% | 2762 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 34,098 psi | 52% | 2595 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 86% | 31,531 psi | 49% | 2595 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 33,997 psi | 52% | 2569 fps | 97.8% |
| Winchester 760 | <<locked>> | 82% | 40,901 psi | 63% | 2776 fps | 95% |
| Winchester StaBALL HD | <<locked>> | 90% | 29,022 psi | 45% | 2595 fps | 95.9% |
| Winchester Supreme 780 | <<locked>> | 96% | 48,762 psi | 75% | 2894 fps | 95.3% |
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 116 powders for .280 Ackley Improved loaded with the .284 | 135gr | Atomic 29 HP. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,130 fps; across all powders the maximum-charge window runs from 1,857 fps to 3,130 fps. Accurate 3100 gives the best case fill at 100 %, and 116 of the 116 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 135.0 gr projectile in 0.284" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, 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-17, ReloadSwiss RS 60 rank at the top here: for .280 Ackley Improved with the .284 | 135gr | Atomic 29 HP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2213, Bofors RP15, Hodgdon H4831 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.