Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 160gr | Sierra GameKing bullet and 97 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, ReloadSwiss RS 70 and Hodgdon Superformance.
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% | 56,101 psi | 86% | 2671 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 57,188 psi | 88% | 2746 fps | 99.2% |
| Accurate 3100ᴾ | <<locked>> | 100% | 55,347 psi | 85% | 2795 fps | 99.8% |
| Accurate 4064 | <<locked>> | 84% | 56,579 psi | 87% | 2726 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 57,392 psi | 88% | 2838 fps | 100% |
| Accurate MAGPROᴾ | <<locked>> | 100% | 57,580 psi | 89% | 2936 fps | 97% |
| ADI AR 2208 | <<locked>> | 86% | 56,492 psi | 87% | 2759 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 58,218 psi | 90% | 2884 fps | 98.9% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 55,840 psi | 86% | 2881 fps | 97.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 55,869 psi | 86% | 2881 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 57,450 psi | 88% | 2782 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 57,595 psi | 89% | 2805 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 58,204 psi | 90% | 2894 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 55,695 psi | 86% | 2861 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 57,682 psi | 89% | 2874 fps | 98.9% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 54,853 psi | 84% | 2877 fps | 98.7% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 51,996 psi | 80% | 2808 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 45,020 psi | 69% | 2740 fps | 99.5% |
| Alliant Reloder-26 | <<locked>> | 98% | 55,782 psi | 86% | 2946 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 50,270 psi | 77% | 2802 fps | 97.8% |
| Bofors RP3 | <<locked>> | 86% | 58,450 psi | 90% | 2799 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 54,853 psi | 84% | 2877 fps | 98.7% |
| Bofors RP7 | <<locked>> | 90% | 57,464 psi | 88% | 2789 fps | 99.4% |
| Hodgdon H380 | <<locked>> | 86% | 58,581 psi | 90% | 2818 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 56,028 psi | 86% | 2838 fps | 99.6% |
| Hodgdon H4350 | <<locked>> | 88% | 55,550 psi | 85% | 2795 fps | 98.8% |
| Hodgdon H4831 | <<locked>> | 98% | 56,101 psi | 86% | 2825 fps | 97% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 58,639 psi | 90% | 2864 fps | 97.4% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 58,610 psi | 90% | 2815 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 56,289 psi | 87% | 2799 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 44,179 psi | 68% | 2772 fps | 97.2% |
| Hodgdon Superformance | <<locked>> | 90% | 56,014 psi | 86% | 2874 fps | 99.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,434 psi | 56% | 1709 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 56,753 psi | 87% | 2759 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 55,912 psi | 86% | 2743 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 58,508 psi | 90% | 2779 fps | 99.7% |
| IMR 4350 | <<locked>> | 94% | 58,450 psi | 90% | 2822 fps | 99.5% |
| IMR 4451 Enduron | <<locked>> | 88% | 55,695 psi | 86% | 2762 fps | 99.4% |
| IMR 4831 | <<locked>> | 94% | 57,856 psi | 89% | 2831 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 55,477 psi | 85% | 2779 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 57,450 psi | 88% | 2812 fps | 97.4% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 53,214 psi | 82% | 2851 fps | 97.2% |
| Lovex S060 | <<locked>> | 82% | 57,493 psi | 88% | 2726 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 56,144 psi | 86% | 2736 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 55,956 psi | 86% | 2762 fps | 99.9% |
| Lovex S070 | <<locked>> | 92% | 57,087 psi | 88% | 2802 fps | 99.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,992 psi | 71% | 2651 fps | 99% |
| Norma 201 | <<locked>> | 82% | 57,392 psi | 88% | 2743 fps | 100% |
| Norma 202 | <<locked>> | 82% | 58,247 psi | 90% | 2740 fps | 100% |
| Norma 203B | <<locked>> | 84% | 56,884 psi | 88% | 2789 fps | 100% |
| Norma 204 | <<locked>> | 92% | 55,956 psi | 86% | 2825 fps | 98.5% |
| Norma MRPᴾ | <<locked>> | 100% | 58,479 psi | 90% | 2963 fps | 99.8% |
| Norma URP | <<locked>> | 92% | 55,898 psi | 86% | 2822 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 57,725 psi | 89% | 2815 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 53,809 psi | 83% | 2871 fps | 97.7% |
| Ramshot Hunter | <<locked>> | 94% | 58,479 psi | 90% | 2877 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 47,906 psi | 74% | 2746 fps | 98.1% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,130 psi | 57% | 1752 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 58,537 psi | 90% | 2805 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 55,361 psi | 85% | 2854 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 57,319 psi | 88% | 2861 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 55,840 psi | 86% | 2894 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 44,164 psi | 68% | 2769 fps | 98.2% |
| Rottweil R 902 | <<locked>> | 84% | 58,204 psi | 90% | 2746 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 58,305 psi | 90% | 2792 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 56,217 psi | 86% | 2799 fps | 97.7% |
| Rottweil R 905 | <<locked>> | 98% | 56,869 psi | 87% | 2858 fps | 98.9% |
| Rottweil R 907 | <<locked>> | 90% | 57,464 psi | 88% | 2789 fps | 99.4% |
| Shooters World Long Rifle | <<locked>> | 90% | 55,956 psi | 86% | 2762 fps | 99.9% |
| Shooters World Precision | <<locked>> | 84% | 56,144 psi | 86% | 2736 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 57,087 psi | 88% | 2802 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 56,304 psi | 87% | 2802 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 57,203 psi | 88% | 2776 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 58,117 psi | 89% | 2671 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 55,709 psi | 86% | 2631 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 55,622 psi | 86% | 2720 fps | 99.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 56,376 psi | 87% | 2854 fps | 98.8% |
| Somchem S335 | <<locked>> | 82% | 57,769 psi | 89% | 2667 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 58,334 psi | 90% | 2789 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 58,044 psi | 89% | 2795 fps | 97.3% |
| Somchem S365 | <<locked>> | 94% | 55,347 psi | 85% | 2822 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 57,508 psi | 88% | 2835 fps | 99.4% |
| Vihtavuori N133 | <<locked>> | 82% | 58,682 psi | 90% | 2651 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 58,798 psi | 90% | 2700 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 55,434 psi | 85% | 2674 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 55,869 psi | 86% | 2713 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 58,044 psi | 89% | 2815 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 53,229 psi | 82% | 2759 fps | 98.7% |
| Vihtavuori N540 | <<locked>> | 84% | 56,913 psi | 88% | 2717 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 57,116 psi | 88% | 2822 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 58,146 psi | 89% | 2884 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 58,682 psi | 90% | 2953 fps | 97.8% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 57,943 psi | 89% | 2785 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 56,028 psi | 86% | 2838 fps | 99.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,847 psi | 72% | 2867 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 57,537 psi | 89% | 2782 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 57,638 psi | 89% | 2831 fps | 98.8% |
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% | 52,576 psi | 81% | 2625 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 50,241 psi | 77% | 2641 fps | 98.3% |
| Accurate 3100 | <<locked>> | 84% | 32,140 psi | 49% | 2365 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 49,864 psi | 77% | 2631 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,232 psi | 59% | 2516 fps | 98.7% |
| Accurate MAGPRO | <<locked>> | 96% | 49,850 psi | 77% | 2812 fps | 95.3% |
| ADI AR 2208 | <<locked>> | 80% | 47,036 psi | 72% | 2612 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 88% | 42,061 psi | 65% | 2602 fps | 95.6% |
| ADI AR 2213 | <<locked>> | 94% | 45,861 psi | 71% | 2707 fps | 95.2% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 51,982 psi | 80% | 2822 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,587 psi | 73% | 2635 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,792 psi | 78% | 2703 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 37,101 psi | 57% | 2520 fps | 98.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 42,250 psi | 65% | 2644 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 41,756 psi | 64% | 2598 fps | 95.6% |
| Alliant Reloder-22 | <<locked>> | 90% | 39,349 psi | 61% | 2592 fps | 95% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,224 psi | 42% | 2287 fps | 96.8% |
| Alliant Reloder-25 | <<locked>> | 90% | 32,822 psi | 50% | 2457 fps | 96% |
| Alliant Reloder-26 | 51.9 gr | 80% | 29,051 psi | 45% | 2392 fps | 95% |
| Bofors RP15 | <<locked>> | 94% | 41,394 psi | 64% | 2635 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 47,935 psi | 74% | 2648 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 39,349 psi | 61% | 2592 fps | 95% |
| Bofors RP7 | <<locked>> | 80% | 42,134 psi | 65% | 2526 fps | 96.8% |
| Hodgdon H380 | <<locked>> | 80% | 48,153 psi | 74% | 2657 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 80% | 40,234 psi | 62% | 2562 fps | 96.9% |
| Hodgdon H4350 | <<locked>> | 80% | 42,989 psi | 66% | 2579 fps | 96.3% |
| Hodgdon H4831 | <<locked>> | 94% | 48,892 psi | 75% | 2710 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 94% | 48,138 psi | 74% | 2697 fps | 95.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,679 psi | 53% | 2418 fps | 99.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 52,547 psi | 81% | 2746 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 38,943 psi | 60% | 2651 fps | 95.1% |
| Hodgdon Superformance | 53.5 gr | 80% | 38,928 psi | 60% | 2569 fps | 96.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,354 psi | 42% | 1529 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,301 psi | 82% | 2710 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,487 psi | 76% | 2644 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,706 psi | 80% | 2674 fps | 99.1% |
| IMR 4350 | <<locked>> | 80% | 37,739 psi | 58% | 2454 fps | 95.5% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,482 psi | 67% | 2556 fps | 97.6% |
| IMR 4831 | <<locked>> | 80% | 36,738 psi | 57% | 2467 fps | 98.5% |
| IMR 4895 | <<locked>> | 80% | 52,098 psi | 80% | 2730 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 47,688 psi | 73% | 2651 fps | 95.3% |
| IMR 7828 SSC | <<locked>> | 96% | 46,644 psi | 72% | 2736 fps | 95.6% |
| Lovex S060 | <<locked>> | 80% | 54,070 psi | 83% | 2677 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,748 psi | 77% | 2641 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 40,973 psi | 63% | 2507 fps | 98.2% |
| Lovex S070 | <<locked>> | 80% | 39,378 psi | 61% | 2490 fps | 96.9% |
| Lovex S071 | <<locked>> | 90% | 33,446 psi | 51% | 2395 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 53,925 psi | 83% | 2694 fps | 100% |
| Norma 202 | <<locked>> | 80% | 54,708 psi | 84% | 2690 fps | 100% |
| Norma 203B | <<locked>> | 80% | 50,140 psi | 77% | 2690 fps | 100% |
| Norma 204 | <<locked>> | 84% | 42,670 psi | 66% | 2595 fps | 95.7% |
| Norma MRP | <<locked>> | 86% | 36,071 psi | 55% | 2546 fps | 95.3% |
| Norma URP | <<locked>> | 80% | 38,014 psi | 58% | 2510 fps | 98.6% |
| Ramshot Big Game | <<locked>> | 80% | 50,415 psi | 78% | 2713 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 46,659 psi | 72% | 2746 fps | 95.9% |
| Ramshot Hunter | <<locked>> | 80% | 36,854 psi | 57% | 2497 fps | 96.8% |
| Ramshot Magnum | <<locked>> | 94% | 38,609 psi | 59% | 2562 fps | 95.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,862 psi | 43% | 1568 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 48,124 psi | 74% | 2641 fps | 99% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,875 psi | 69% | 2694 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,913 psi | 58% | 2530 fps | 98.4% |
| ReloadSwiss RS 70 | 51.4 gr | 80% | 36,651 psi | 56% | 2536 fps | 97.8% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 35,853 psi | 55% | 2569 fps | 95% |
| Rottweil R 902 | <<locked>> | 80% | 51,605 psi | 79% | 2651 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 45,281 psi | 70% | 2598 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 46,673 psi | 72% | 2641 fps | 95.7% |
| Rottweil R 905 | <<locked>> | 88% | 40,843 psi | 63% | 2582 fps | 95.6% |
| Rottweil R 907 | <<locked>> | 80% | 42,134 psi | 65% | 2526 fps | 96.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,973 psi | 63% | 2507 fps | 98.2% |
| Shooters World Precision | <<locked>> | 80% | 49,748 psi | 77% | 2641 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 39,378 psi | 61% | 2490 fps | 96.9% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 46,369 psi | 71% | 2651 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 53,795 psi | 83% | 2726 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 54,795 psi | 84% | 2628 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,427 psi | 71% | 2503 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,205 psi | 62% | 2454 fps | 96.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 40,466 psi | 62% | 2575 fps | 95.4% |
| Somchem S335 | <<locked>> | 80% | 54,360 psi | 84% | 2625 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 45,339 psi | 70% | 2592 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 47,747 psi | 73% | 2631 fps | 95% |
| Somchem S365 | <<locked>> | 80% | 34,389 psi | 53% | 2467 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 36,550 psi | 56% | 2461 fps | 95% |
| Vihtavuori N133 | <<locked>> | 80% | 55,376 psi | 85% | 2612 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 51,953 psi | 80% | 2615 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 52,025 psi | 80% | 2628 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,453 psi | 67% | 2526 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 39,349 psi | 61% | 2507 fps | 98.8% |
| Vihtavuori N165 | <<locked>> | 90% | 38,203 psi | 59% | 2490 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 50,053 psi | 77% | 2621 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,725 psi | 60% | 2507 fps | 98.6% |
| Vihtavuori N555 | <<locked>> | 80% | 30,226 psi | 47% | 2365 fps | 96.9% |
| Vihtavuori N560 | <<locked>> | 94% | 47,805 psi | 74% | 2772 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,479 psi | 59% | 2480 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 40,234 psi | 62% | 2562 fps | 96.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,149 psi | 37% | 2260 fps | 95.4% |
| Winchester StaBALL Match | <<locked>> | 80% | 53,795 psi | 83% | 2733 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 40,944 psi | 63% | 2552 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 97 powders for .280 Ackley Improved loaded with the .284 | 160gr | Sierra GameKing. Norma MRP delivers the highest muzzle velocity at 2,963 fps; across all powders the maximum-charge window runs from 1,709 fps to 2,963 fps. Accurate 3100 gives the best case fill at 100 %, and 97 of the 97 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 160.0 gr projectile in 0.284" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate MAGPRO, 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. Alliant Reloder-26, ReloadSwiss RS 70, Hodgdon Superformance rank at the top here: for .280 Ackley Improved with the .284 | 160gr | Sierra GameKing 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.