Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 140gr | Barnes X S bullet and 96 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.
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>> | 82% | 55,651 psi | 86% | 2825 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 55,448 psi | 85% | 2867 fps | 97.9% |
| Accurate 3100ᴾ | <<locked>> | 100% | 52,910 psi | 81% | 2910 fps | 98.9% |
| Accurate 4064 | <<locked>> | 84% | 55,767 psi | 86% | 2877 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 55,230 psi | 85% | 2966 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 82% | 56,985 psi | 88% | 2940 fps | 100% |
| ADI AR 2208 | <<locked>> | 88% | 57,609 psi | 89% | 2936 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 55,448 psi | 85% | 2992 fps | 97.2% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 56,855 psi | 87% | 3068 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 98% | 55,347 psi | 85% | 2989 fps | 97.2% |
| Alliant Power Pro Varmint | <<locked>> | 98% | 55,347 psi | 85% | 2989 fps | 97.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 58,668 psi | 90% | 2966 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 55,666 psi | 86% | 2940 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 96% | 58,508 psi | 90% | 3068 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 90% | 56,550 psi | 87% | 3045 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 58,059 psi | 89% | 3035 fps | 97.8% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 51,996 psi | 80% | 2979 fps | 96.8% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 49,197 psi | 76% | 2927 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 43,381 psi | 67% | 2838 fps | 97.9% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 56,304 psi | 87% | 3123 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 56,478 psi | 87% | 2953 fps | 100% |
| Bofors RP3 | <<locked>> | 86% | 56,753 psi | 87% | 2940 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 51,996 psi | 80% | 2979 fps | 96.8% |
| Bofors RP7 | <<locked>> | 90% | 55,637 psi | 86% | 2910 fps | 98.1% |
| Hodgdon H380 | <<locked>> | 86% | 56,637 psi | 87% | 2946 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 92% | 56,898 psi | 88% | 3012 fps | 98.8% |
| Hodgdon H4350 | <<locked>> | 90% | 56,623 psi | 87% | 2966 fps | 97.7% |
| Hodgdon H4895 | <<locked>> | 82% | 57,580 psi | 89% | 2949 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 55,434 psi | 85% | 2940 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 57,392 psi | 88% | 2982 fps | 100% |
| Hodgdon Superformance | <<locked>> | 92% | 56,724 psi | 87% | 3041 fps | 98.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,506 psi | 56% | 1821 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 58,160 psi | 89% | 2946 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 58,160 psi | 89% | 2927 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 57,464 psi | 88% | 2923 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 56,623 psi | 87% | 2904 fps | 98.7% |
| IMR 4350 | <<locked>> | 94% | 55,985 psi | 86% | 2936 fps | 98.2% |
| IMR 4451 Enduron | <<locked>> | 90% | 57,058 psi | 88% | 2936 fps | 98.7% |
| IMR 4831 | <<locked>> | 96% | 58,697 psi | 90% | 3002 fps | 100% |
| IMR 4895 | <<locked>> | 84% | 57,087 psi | 88% | 2969 fps | 100% |
| IMR 4955 Enduronᴾ | <<locked>> | 100% | 58,508 psi | 90% | 2972 fps | 96% |
| Lovex D073.6 | <<locked>> | 82% | 57,812 psi | 89% | 2917 fps | 100% |
| Lovex S060 | <<locked>> | 82% | 55,492 psi | 85% | 2858 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 57,957 psi | 89% | 2923 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 57,334 psi | 88% | 2936 fps | 99.5% |
| Lovex S070 | <<locked>> | 94% | 58,595 psi | 90% | 2976 fps | 99.1% |
| Lovex S071ᴾ | <<locked>> | 100% | 44,686 psi | 69% | 2766 fps | 97.5% |
| Norma 201 | <<locked>> | 82% | 56,144 psi | 86% | 2887 fps | 100% |
| Norma 202 | <<locked>> | 82% | 56,521 psi | 87% | 2881 fps | 100% |
| Norma 203B | <<locked>> | 86% | 58,421 psi | 90% | 2979 fps | 100% |
| Norma 204 | <<locked>> | 94% | 56,826 psi | 87% | 2989 fps | 97.3% |
| Norma MRPᴾ | <<locked>> | 100% | 55,143 psi | 85% | 3071 fps | 98.6% |
| Norma URP | <<locked>> | 94% | 56,956 psi | 88% | 2999 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 84% | 55,303 psi | 85% | 2946 fps | 100% |
| Ramshot Hunter | <<locked>> | 94% | 55,680 psi | 86% | 2999 fps | 99.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,260 psi | 57% | 1864 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 56,536 psi | 87% | 2927 fps | 99.1% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 56,376 psi | 87% | 3005 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 56,014 psi | 86% | 3041 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 58,175 psi | 89% | 3038 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 56,449 psi | 87% | 3064 fps | 99.9% |
| Rottweil R 902 | <<locked>> | 84% | 56,855 psi | 87% | 2887 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 56,521 psi | 87% | 2933 fps | 100% |
| Rottweil R 904 | <<locked>> | 98% | 57,276 psi | 88% | 2963 fps | 96.4% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 57,638 psi | 89% | 3025 fps | 97.8% |
| Rottweil R 907 | <<locked>> | 90% | 55,637 psi | 86% | 2910 fps | 98.1% |
| Shooters World Long Rifle | <<locked>> | 92% | 57,334 psi | 88% | 2936 fps | 99.5% |
| Shooters World Match Rifle | <<locked>> | 82% | 57,812 psi | 89% | 2917 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 57,957 psi | 89% | 2923 fps | 100% |
| Shooters World SW4350 | <<locked>> | 94% | 58,595 psi | 90% | 2976 fps | 99.1% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 57,377 psi | 88% | 2986 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 58,378 psi | 90% | 2943 fps | 99.8% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 58,610 psi | 90% | 2959 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 56,536 psi | 87% | 2812 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 57,130 psi | 88% | 2812 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 57,145 psi | 88% | 2884 fps | 98.7% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 57,116 psi | 88% | 3018 fps | 97.7% |
| Somchem S335 | <<locked>> | 82% | 56,434 psi | 87% | 2812 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 57,537 psi | 89% | 2927 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 56,246 psi | 87% | 2923 fps | 100% |
| Somchem S365 | <<locked>> | 96% | 55,898 psi | 86% | 3005 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 58,581 psi | 90% | 3002 fps | 98.6% |
| Vihtavuori N133 | <<locked>> | 82% | 56,869 psi | 87% | 2795 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 56,739 psi | 87% | 2844 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 56,768 psi | 87% | 2858 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 57,493 psi | 88% | 2897 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 55,608 psi | 86% | 2940 fps | 99.9% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 50,488 psi | 78% | 2858 fps | 96.8% |
| Vihtavuori N540 | <<locked>> | 86% | 58,523 psi | 90% | 2904 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 58,218 psi | 90% | 2999 fps | 99.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 55,376 psi | 85% | 3012 fps | 100% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 58,624 psi | 90% | 2956 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 56,898 psi | 88% | 3012 fps | 98.8% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 44,773 psi | 69% | 2979 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 55,434 psi | 85% | 2920 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 54,752 psi | 84% | 2933 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 2495 | <<locked>> | 80% | 52,373 psi | 81% | 2779 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 48,979 psi | 75% | 2756 fps | 96.7% |
| Accurate 3100 | <<locked>> | 88% | 36,332 psi | 56% | 2589 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 49,458 psi | 76% | 2782 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 37,724 psi | 58% | 2638 fps | 97.3% |
| ADI AR 2206H | <<locked>> | 80% | 53,679 psi | 83% | 2887 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 45,759 psi | 70% | 2740 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 94% | 48,965 psi | 75% | 2877 fps | 95.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 49,690 psi | 76% | 2946 fps | 99.8% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 46,122 psi | 71% | 2822 fps | 95% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 46,122 psi | 71% | 2822 fps | 95% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 46,369 psi | 71% | 2766 fps | 99.9% |
| Alliant Reloder-15 | <<locked>> | 80% | 49,371 psi | 76% | 2835 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,260 psi | 56% | 2635 fps | 97.1% |
| Alliant Reloder-17 | 50.6 gr | 80% | 40,611 psi | 62% | 2759 fps | 99.5% |
| Alliant Reloder-19 | <<locked>> | 94% | 48,414 psi | 74% | 2867 fps | 95.7% |
| Alliant Reloder-22 | <<locked>> | 96% | 46,035 psi | 71% | 2867 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 82% | 29,022 psi | 45% | 2454 fps | 95.7% |
| Alliant Reloder-25 | <<locked>> | 94% | 36,390 psi | 56% | 2667 fps | 95.4% |
| Alliant Reloder-26 | <<locked>> | 86% | 35,128 psi | 54% | 2684 fps | 96% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 52,997 psi | 82% | 2897 fps | 99.8% |
| Bofors RP3 | <<locked>> | 80% | 46,949 psi | 72% | 2782 fps | 100% |
| Bofors RP5 | <<locked>> | 96% | 46,035 psi | 71% | 2867 fps | 95.2% |
| Bofors RP7 | <<locked>> | 82% | 44,048 psi | 68% | 2697 fps | 95.7% |
| Hodgdon H380 | <<locked>> | 80% | 47,065 psi | 72% | 2785 fps | 98.8% |
| Hodgdon H414 | <<locked>> | 82% | 41,568 psi | 64% | 2726 fps | 95.6% |
| Hodgdon H4350 | <<locked>> | 84% | 47,079 psi | 72% | 2795 fps | 95.7% |
| Hodgdon H4895 | <<locked>> | 80% | 54,273 psi | 83% | 2900 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,040 psi | 52% | 2536 fps | 97.9% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 50,531 psi | 78% | 2877 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 43,352 psi | 67% | 2795 fps | 95.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,543 psi | 42% | 1631 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 51,561 psi | 79% | 2841 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 54,607 psi | 84% | 2877 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 48,138 psi | 74% | 2772 fps | 99.7% |
| IMR 4166 Enduron | <<locked>> | 80% | 50,038 psi | 77% | 2792 fps | 97.6% |
| IMR 4350 | <<locked>> | 86% | 44,179 psi | 68% | 2726 fps | 95.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 42,453 psi | 65% | 2667 fps | 95.7% |
| IMR 4831 | <<locked>> | 80% | 36,143 psi | 56% | 2589 fps | 96.9% |
| IMR 4895 | <<locked>> | 80% | 50,633 psi | 78% | 2864 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 55,085 psi | 85% | 2917 fps | 95.3% |
| Lovex D073.6 | <<locked>> | 80% | 54,114 psi | 83% | 2864 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 52,576 psi | 81% | 2812 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 48,704 psi | 75% | 2779 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 40,451 psi | 62% | 2628 fps | 96.7% |
| Lovex S070 | <<locked>> | 82% | 41,118 psi | 63% | 2661 fps | 95.7% |
| Lovex S071 | <<locked>> | 94% | 37,260 psi | 57% | 2608 fps | 95.3% |
| Norma 201 | <<locked>> | 80% | 52,881 psi | 81% | 2835 fps | 100% |
| Norma 202 | <<locked>> | 80% | 53,214 psi | 82% | 2831 fps | 100% |
| Norma 203B | <<locked>> | 80% | 48,762 psi | 75% | 2822 fps | 99.9% |
| Norma 204 | <<locked>> | 88% | 46,717 psi | 72% | 2812 fps | 95% |
| Norma MRP | <<locked>> | 92% | 42,409 psi | 65% | 2825 fps | 95.7% |
| Norma URP | <<locked>> | 80% | 36,985 psi | 57% | 2625 fps | 97% |
| Ramshot Big Game | <<locked>> | 80% | 48,544 psi | 75% | 2838 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 82% | 38,218 psi | 59% | 2661 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,036 psi | 43% | 1670 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 46,876 psi | 72% | 2762 fps | 97.6% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 52,678 psi | 81% | 2946 fps | 99.9% |
| ReloadSwiss RS 60 | 50.6 gr | 80% | 42,960 psi | 66% | 2818 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 36,956 psi | 57% | 2644 fps | 96.7% |
| ReloadSwiss RS 70 | 51.4 gr | 80% | 35,911 psi | 55% | 2641 fps | 95.7% |
| Rottweil R 902 | <<locked>> | 80% | 50,459 psi | 78% | 2789 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 44,266 psi | 68% | 2726 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 96% | 53,867 psi | 83% | 2907 fps | 95.6% |
| Rottweil R 905 | <<locked>> | 94% | 47,703 psi | 73% | 2854 fps | 95.7% |
| Rottweil R 907 | <<locked>> | 82% | 44,048 psi | 68% | 2697 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,451 psi | 62% | 2628 fps | 96.7% |
| Shooters World Match Rifle | <<locked>> | 80% | 54,114 psi | 83% | 2864 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 48,704 psi | 75% | 2779 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 41,118 psi | 63% | 2661 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 44,614 psi | 69% | 2769 fps | 99.5% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 54,752 psi | 84% | 2890 fps | 99.6% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 51,851 psi | 80% | 2854 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 53,171 psi | 82% | 2762 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 45,078 psi | 69% | 2631 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 39,755 psi | 61% | 2572 fps | 95.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 47,253 psi | 73% | 2848 fps | 95.6% |
| Somchem S335 | <<locked>> | 80% | 53,229 psi | 82% | 2766 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 53,911 psi | 83% | 2871 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 44,483 psi | 68% | 2726 fps | 99.7% |
| Somchem S365 | <<locked>> | 80% | 33,692 psi | 52% | 2585 fps | 99% |
| Somchem S385 | <<locked>> | 90% | 43,033 psi | 66% | 2733 fps | 95.4% |
| Vihtavuori N133 | <<locked>> | 80% | 53,519 psi | 82% | 2749 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 50,328 psi | 77% | 2753 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 50,270 psi | 77% | 2762 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 42,351 psi | 65% | 2651 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 80% | 38,377 psi | 59% | 2621 fps | 97.3% |
| Vihtavuori N165 | <<locked>> | 96% | 44,614 psi | 69% | 2749 fps | 95.3% |
| Vihtavuori N540 | <<locked>> | 80% | 48,820 psi | 75% | 2759 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 37,956 psi | 58% | 2625 fps | 97% |
| Vihtavuori N555 | <<locked>> | 80% | 29,892 psi | 46% | 2480 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 37,391 psi | 58% | 2589 fps | 99% |
| Winchester 760 | <<locked>> | 82% | 41,568 psi | 64% | 2726 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 84% | 27,557 psi | 42% | 2484 fps | 95.4% |
| Winchester StaBALL Match | <<locked>> | 80% | 51,996 psi | 80% | 2864 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 47,935 psi | 74% | 2818 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 96 powders for .280 Ackley Improved loaded with the .284 | 140gr | Barnes X S. Alliant Reloder-26 delivers the highest muzzle velocity at 3,123 fps; across all powders the maximum-charge window runs from 1,821 fps to 3,123 fps. Accurate 3100 gives the best case fill at 100 %, and 96 of the 96 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 140.0 gr projectile in 0.284" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-19, Alliant Reloder-22 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 | 140gr | Barnes X S 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.