Load Specifications
Bullet:.284 | 150gr | Osprey Virtus
Bullet Manufacturer:Virtus
Bullet Weight:150 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:1:9.0
Load data in caliber .280 Ackley Improved with .284 | 150gr | Osprey Virtus bullet and 107 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-17, ReloadSwiss RS 60 and ReloadSwiss RS 70.
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% | 57,595 psi | 89% | 2743 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 56,811 psi | 87% | 2769 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 56,797 psi | 87% | 2825 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 56,797 psi | 87% | 2799 fps | 98.5% |
| Accurate 3100ᴾ | <<locked>> | 100% | 47,906 psi | 74% | 2756 fps | 98.6% |
| Accurate 4064 | <<locked>> | 88% | 56,971 psi | 88% | 2822 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 58,015 psi | 89% | 2930 fps | 100% |
| ADI AR 2206H | <<locked>> | 84% | 56,884 psi | 88% | 2858 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 58,247 psi | 90% | 2861 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 55,651 psi | 86% | 2913 fps | 97.7% |
| ADI Benchmark 8208 | <<locked>> | 82% | 55,550 psi | 85% | 2799 fps | 100% |
| Alliant AR-Comp | <<locked>> | 82% | 57,363 psi | 88% | 2769 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 57,363 psi | 88% | 2986 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 58,784 psi | 90% | 2884 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 86% | 55,463 psi | 85% | 2854 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 96% | 55,114 psi | 85% | 2930 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 92% | 56,681 psi | 87% | 2963 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 54,636 psi | 84% | 2900 fps | 97.7% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 48,254 psi | 74% | 2838 fps | 96.5% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 45,440 psi | 70% | 2785 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 39,610 psi | 61% | 2690 fps | 97.5% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 51,764 psi | 80% | 2969 fps | 99.9% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 56,927 psi | 88% | 2874 fps | 100% |
| Bofors RP3 | <<locked>> | 88% | 55,695 psi | 86% | 2844 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 48,254 psi | 74% | 2838 fps | 96.5% |
| Bofors RP7 | <<locked>> | 92% | 55,492 psi | 85% | 2828 fps | 98.5% |
| Hodgdon Benchmark | <<locked>> | 82% | 57,029 psi | 88% | 2782 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 82% | 55,550 psi | 85% | 2835 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 56,565 psi | 87% | 2867 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 92% | 58,595 psi | 90% | 2953 fps | 99.3% |
| Hodgdon H4350 | <<locked>> | 96% | 58,711 psi | 90% | 2917 fps | 98.5% |
| Hodgdon H4895 | <<locked>> | 84% | 57,551 psi | 89% | 2864 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 98% | 55,376 psi | 85% | 2854 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 58,073 psi | 89% | 2907 fps | 100% |
| Hodgdon Superformance | <<locked>> | 94% | 57,435 psi | 88% | 2972 fps | 99.1% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,897 psi | 55% | 1745 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 57,827 psi | 89% | 2854 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 56,608 psi | 87% | 2822 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 56,840 psi | 87% | 2831 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 90% | 55,970 psi | 86% | 2812 fps | 99% |
| IMR 4350 | <<locked>> | 96% | 56,246 psi | 87% | 2861 fps | 98.7% |
| IMR 4451 Enduron | <<locked>> | 92% | 57,217 psi | 88% | 2858 fps | 99.1% |
| IMR 4831ᴾ | <<locked>> | 100% | 55,550 psi | 85% | 2877 fps | 100% |
| IMR 4895 | <<locked>> | 86% | 56,927 psi | 88% | 2884 fps | 100% |
| IMR 4955 Enduronᴾ | <<locked>> | 100% | 55,274 psi | 85% | 2844 fps | 95.9% |
| IMR 8208 XBR | <<locked>> | 82% | 55,550 psi | 85% | 2799 fps | 100% |
| Lovex D073.6 | <<locked>> | 84% | 57,101 psi | 88% | 2828 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 56,028 psi | 86% | 2782 fps | 100% |
| Lovex S062 | <<locked>> | 88% | 57,348 psi | 88% | 2835 fps | 100% |
| Lovex S065 | <<locked>> | 94% | 56,811 psi | 87% | 2848 fps | 99.7% |
| Lovex S070 | <<locked>> | 96% | 58,175 psi | 89% | 2894 fps | 99.4% |
| Lovex S071ᴾ | <<locked>> | 100% | 39,769 psi | 61% | 2608 fps | 96.8% |
| Norma 201 | <<locked>> | 84% | 55,288 psi | 85% | 2795 fps | 100% |
| Norma 202 | <<locked>> | 84% | 56,231 psi | 87% | 2795 fps | 100% |
| Norma 203B | <<locked>> | 88% | 58,102 psi | 89% | 2890 fps | 100% |
| Norma 204 | <<locked>> | 96% | 57,043 psi | 88% | 2913 fps | 97.8% |
| Norma MRPᴾ | <<locked>> | 100% | 51,126 psi | 79% | 2923 fps | 98.5% |
| Norma URP | <<locked>> | 96% | 56,797 psi | 87% | 2913 fps | 100% |
| Ramshot Big Game | <<locked>> | 86% | 55,332 psi | 85% | 2867 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 54,752 psi | 84% | 2949 fps | 96.7% |
| Ramshot Hunter | <<locked>> | 96% | 55,492 psi | 85% | 2913 fps | 99.5% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 47,050 psi | 72% | 2792 fps | 96.7% |
| Ramshot TAC | <<locked>> | 82% | 55,869 psi | 86% | 2831 fps | 99.7% |
| Ramshot Wild Boar | <<locked>> | 82% | 55,782 psi | 86% | 2841 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,506 psi | 56% | 1785 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 56,536 psi | 87% | 2848 fps | 99.4% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 56,347 psi | 87% | 2923 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 56,347 psi | 87% | 2956 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 58,015 psi | 89% | 2953 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 56,710 psi | 87% | 2982 fps | 100% |
| Rottweil R 901 | <<locked>> | 82% | 56,231 psi | 87% | 2776 fps | 100% |
| Rottweil R 902 | <<locked>> | 86% | 56,115 psi | 86% | 2799 fps | 100% |
| Rottweil R 903 | <<locked>> | 90% | 55,550 psi | 85% | 2838 fps | 100% |
| Rottweil R 904ᴾ | <<locked>> | 100% | 57,522 psi | 88% | 2887 fps | 97% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 53,795 psi | 83% | 2887 fps | 97.7% |
| Rottweil R 907 | <<locked>> | 92% | 55,492 psi | 85% | 2828 fps | 98.5% |
| Shooters World Long Rifle | <<locked>> | 94% | 56,811 psi | 87% | 2848 fps | 99.7% |
| Shooters World Match Rifle | <<locked>> | 84% | 57,101 psi | 88% | 2828 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 57,348 psi | 88% | 2835 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 58,175 psi | 89% | 2894 fps | 99.4% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 57,595 psi | 89% | 2904 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 58,421 psi | 90% | 2864 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 55,376 psi | 85% | 2828 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 56,811 psi | 87% | 2733 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 57,566 psi | 89% | 2736 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 57,130 psi | 88% | 2808 fps | 99.1% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 53,301 psi | 82% | 2881 fps | 97.6% |
| Somchem S335 | <<locked>> | 84% | 55,999 psi | 86% | 2726 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 57,986 psi | 89% | 2848 fps | 100% |
| Somchem S355 | <<locked>> | 90% | 55,883 psi | 86% | 2838 fps | 100% |
| Somchem S365 | <<locked>> | 98% | 55,724 psi | 86% | 2917 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 54,505 psi | 84% | 2864 fps | 98.4% |
| Unknown powder | <<locked>> | 94% | 57,537 psi | 89% | 2920 fps | 99.9% |
| Vihtavuori N133 | <<locked>> | 84% | 57,319 psi | 88% | 2717 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 56,434 psi | 87% | 2759 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 56,797 psi | 87% | 2776 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 57,363 psi | 88% | 2815 fps | 100% |
| Vihtavuori N160 | <<locked>> | 94% | 55,376 psi | 85% | 2858 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 46,760 psi | 72% | 2723 fps | 96.6% |
| Vihtavuori N530 | <<locked>> | 82% | 56,246 psi | 87% | 2805 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 58,784 psi | 90% | 2822 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 58,146 psi | 89% | 2913 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 50,604 psi | 78% | 2861 fps | 100% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 55,376 psi | 85% | 2828 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 58,595 psi | 90% | 2953 fps | 99.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 40,582 psi | 62% | 2818 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 57,087 psi | 88% | 2890 fps | 97.9% |
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% | 54,157 psi | 83% | 2697 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 46,630 psi | 72% | 2625 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 53,084 psi | 82% | 2772 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 40,683 psi | 63% | 2523 fps | 95.1% |
| Accurate 3100 | <<locked>> | 92% | 36,303 psi | 56% | 2533 fps | 95.7% |
| Accurate 4064 | <<locked>> | 80% | 44,193 psi | 68% | 2631 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 33,040 psi | 51% | 2470 fps | 96.4% |
| ADI AR 2206H | <<locked>> | 80% | 50,169 psi | 77% | 2753 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 42,540 psi | 65% | 2605 fps | 99.2% |
| ADI AR 2209 | <<locked>> | 94% | 45,600 psi | 70% | 2740 fps | 95.4% |
| ADI Benchmark 8208 | <<locked>> | 80% | 52,301 psi | 80% | 2753 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 53,780 psi | 83% | 2723 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 46,369 psi | 71% | 2805 fps | 99.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 42,554 psi | 65% | 2628 fps | 99.9% |
| Alliant Reloder-15 | <<locked>> | 80% | 45,672 psi | 70% | 2694 fps | 99.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 33,040 psi | 51% | 2490 fps | 96.6% |
| Alliant Reloder-17 | 48.9 gr | 80% | 37,188 psi | 57% | 2615 fps | 99.2% |
| Alliant Reloder-19 | <<locked>> | 94% | 44,933 psi | 69% | 2730 fps | 95.4% |
| Alliant Reloder-22 | <<locked>> | 98% | 45,049 psi | 69% | 2779 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 84% | 26,919 psi | 41% | 2339 fps | 95.3% |
| Alliant Reloder-25 | <<locked>> | 96% | 34,867 psi | 54% | 2572 fps | 95.6% |
| Alliant Reloder-26 | <<locked>> | 88% | 33,286 psi | 51% | 2579 fps | 95.9% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 49,734 psi | 77% | 2762 fps | 99.8% |
| Bofors RP3 | <<locked>> | 80% | 42,540 psi | 65% | 2635 fps | 99.9% |
| Bofors RP5 | <<locked>> | 98% | 45,049 psi | 69% | 2779 fps | 95.6% |
| Bofors RP7 | <<locked>> | 82% | 40,408 psi | 62% | 2559 fps | 95.2% |
| Hodgdon Benchmark | <<locked>> | 80% | 53,737 psi | 83% | 2733 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 51,692 psi | 80% | 2779 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 43,134 psi | 66% | 2641 fps | 98.6% |
| Hodgdon H414 | <<locked>> | 80% | 38,551 psi | 59% | 2595 fps | 95.3% |
| Hodgdon H4350 | <<locked>> | 86% | 42,873 psi | 66% | 2641 fps | 95.1% |
| Hodgdon H4895 | <<locked>> | 80% | 50,691 psi | 78% | 2762 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 30,443 psi | 47% | 2388 fps | 97.3% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 44,338 psi | 68% | 2694 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 39,697 psi | 61% | 2651 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,774 psi | 41% | 1558 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 45,063 psi | 69% | 2654 fps | 99.9% |
| IMR 3031 | <<locked>> | 80% | 46,615 psi | 72% | 2677 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 41,742 psi | 64% | 2582 fps | 99.2% |
| IMR 4166 Enduron | <<locked>> | 80% | 41,205 psi | 63% | 2549 fps | 96.1% |
| IMR 4350 | <<locked>> | 86% | 40,915 psi | 63% | 2592 fps | 95.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 39,305 psi | 60% | 2536 fps | 95.4% |
| IMR 4831 | <<locked>> | 82% | 30,922 psi | 48% | 2402 fps | 95.6% |
| IMR 4895 | <<locked>> | 80% | 46,862 psi | 72% | 2723 fps | 99.9% |
| IMR 4955 Enduron | <<locked>> | 98% | 52,069 psi | 80% | 2792 fps | 95.2% |
| IMR 8208 XBR | <<locked>> | 80% | 52,301 psi | 80% | 2753 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 49,879 psi | 77% | 2726 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 49,458 psi | 76% | 2680 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 44,686 psi | 69% | 2635 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 36,767 psi | 57% | 2484 fps | 96.2% |
| Lovex S070 | <<locked>> | 82% | 37,188 psi | 57% | 2513 fps | 95.1% |
| Lovex S071 | <<locked>> | 96% | 34,809 psi | 54% | 2500 fps | 95.1% |
| Norma 201 | <<locked>> | 80% | 48,950 psi | 75% | 2700 fps | 100% |
| Norma 202 | <<locked>> | 80% | 49,443 psi | 76% | 2700 fps | 100% |
| Norma 203B | <<locked>> | 80% | 45,049 psi | 69% | 2680 fps | 99.8% |
| Norma 204 | <<locked>> | 90% | 46,398 psi | 71% | 2736 fps | 95.6% |
| Norma MRP | <<locked>> | 92% | 38,551 psi | 59% | 2671 fps | 95% |
| Norma URP | <<locked>> | 80% | 33,344 psi | 51% | 2477 fps | 96.3% |
| Ramshot Big Game | <<locked>> | 80% | 45,020 psi | 69% | 2700 fps | 99.7% |
| Ramshot Grand | <<locked>> | 98% | 50,531 psi | 78% | 2877 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 84% | 37,028 psi | 57% | 2572 fps | 95.8% |
| Ramshot Magnum | <<locked>> | 98% | 43,714 psi | 67% | 2730 fps | 95.8% |
| Ramshot TAC | <<locked>> | 80% | 52,156 psi | 80% | 2772 fps | 99.4% |
| Ramshot Wild Boar | <<locked>> | 80% | 52,257 psi | 80% | 2792 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,180 psi | 42% | 1594 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 43,497 psi | 67% | 2628 fps | 97.3% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 49,037 psi | 75% | 2808 fps | 99.9% |
| ReloadSwiss RS 60 | 48.9 gr | 80% | 39,595 psi | 61% | 2677 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 32,808 psi | 50% | 2487 fps | 95.9% |
| ReloadSwiss RS 70 | 50.9 gr | 82% | 34,882 psi | 54% | 2556 fps | 96% |
| Rottweil R 901 | <<locked>> | 80% | 52,982 psi | 82% | 2726 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 46,485 psi | 72% | 2651 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 39,972 psi | 61% | 2579 fps | 99.6% |
| Rottweil R 904 | <<locked>> | 96% | 50,531 psi | 78% | 2776 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 94% | 43,816 psi | 67% | 2710 fps | 95.3% |
| Rottweil R 907 | <<locked>> | 82% | 40,408 psi | 62% | 2559 fps | 95.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 36,767 psi | 57% | 2484 fps | 96.2% |
| Shooters World Match Rifle | <<locked>> | 80% | 49,879 psi | 77% | 2726 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 44,686 psi | 69% | 2635 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 37,188 psi | 57% | 2513 fps | 95.1% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 41,191 psi | 63% | 2631 fps | 99.3% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 50,894 psi | 78% | 2753 fps | 99.5% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 48,617 psi | 75% | 2723 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 50,154 psi | 77% | 2641 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 42,105 psi | 65% | 2510 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 38,479 psi | 59% | 2484 fps | 95.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 43,395 psi | 67% | 2703 fps | 95.2% |
| Somchem S335 | <<locked>> | 80% | 49,734 psi | 77% | 2638 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 50,560 psi | 78% | 2743 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 40,611 psi | 62% | 2582 fps | 99.5% |
| Somchem S365 | <<locked>> | 80% | 29,733 psi | 46% | 2425 fps | 98.4% |
| Somchem S385 | <<locked>> | 92% | 41,727 psi | 64% | 2641 fps | 95.6% |
| Unknown powder | <<locked>> | 80% | 36,172 psi | 56% | 2533 fps | 96.6% |
| Vihtavuori N133 | <<locked>> | 80% | 50,720 psi | 78% | 2628 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 46,673 psi | 72% | 2625 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 47,007 psi | 72% | 2635 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 38,725 psi | 60% | 2516 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 80% | 34,722 psi | 53% | 2477 fps | 96.8% |
| Vihtavuori N165 | <<locked>> | 98% | 43,903 psi | 68% | 2671 fps | 95.8% |
| Vihtavuori N530 | <<locked>> | 80% | 52,576 psi | 81% | 2749 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 45,295 psi | 70% | 2625 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 34,171 psi | 53% | 2477 fps | 96.4% |
| Vihtavuori N555 | <<locked>> | 84% | 29,457 psi | 45% | 2418 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 34,084 psi | 52% | 2451 fps | 98.6% |
| Winchester 760 | <<locked>> | 80% | 38,551 psi | 59% | 2595 fps | 95.3% |
| Winchester StaBALL HD | <<locked>> | 88% | 27,064 psi | 42% | 2425 fps | 96.1% |
| Winchester Supreme 780 | <<locked>> | 94% | 45,701 psi | 70% | 2707 fps | 95.5% |
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 107 powders for .280 Ackley Improved loaded with the .284 | 150gr | Osprey Virtus. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 2,986 fps; across all powders the maximum-charge window runs from 1,745 fps to 2,986 fps. Accurate 3100 gives the best case fill at 100 %, and 107 of the 107 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 150.0 gr projectile in 0.284" calls for a 1:9.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, Alliant Reloder-19 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 Reloder-17, ReloadSwiss RS 60, ReloadSwiss RS 70 rank at the top here: for .280 Ackley Improved with the .284 | 150gr | Osprey Virtus 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.