Load Specifications
Load data in caliber .243 Ackley Improved with .243 | 100gr | Sierra SP SemiSp bullet and 59 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Norma MRP, ReloadSwiss RS 70 and Alliant Reloder-26.
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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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 96% | 48,254 psi | 87% | 2913 fps | 98.8% |
| Accurate 4350 | <<locked>> | 86% | 46,673 psi | 84% | 2910 fps | 99.5% |
| ADI AR 2208 | <<locked>> | 82% | 49,734 psi | 90% | 2900 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 92% | 47,863 psi | 87% | 2946 fps | 96.4% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 47,848 psi | 87% | 2943 fps | 96.4% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 47,848 psi | 87% | 2943 fps | 96.4% |
| Alliant Reloder-16 | <<locked>> | 88% | 47,529 psi | 86% | 2969 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 84% | 48,124 psi | 87% | 2989 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 92% | 47,268 psi | 86% | 2933 fps | 96.4% |
| Alliant Reloder-22 | <<locked>> | 96% | 47,993 psi | 87% | 2992 fps | 96.7% |
| Alliant Reloder-23 | <<locked>> | 98% | 48,486 psi | 88% | 2992 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,889 psi | 81% | 2963 fps | 99% |
| Alliant Reloder-26 | <<locked>> | 94% | 47,892 psi | 87% | 3058 fps | 99.7% |
| Bofors RP15 | <<locked>> | 98% | 46,949 psi | 85% | 2969 fps | 96.3% |
| Bofors RP5 | <<locked>> | 96% | 47,993 psi | 87% | 2992 fps | 96.7% |
| Bofors RP7 | <<locked>> | 84% | 47,616 psi | 86% | 2861 fps | 97.4% |
| Hodgdon H414 | <<locked>> | 86% | 48,762 psi | 88% | 2959 fps | 98.2% |
| Hodgdon H4350 | <<locked>> | 84% | 48,762 psi | 88% | 2920 fps | 97% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 47,892 psi | 87% | 2900 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 44,135 psi | 80% | 2992 fps | 96.2% |
| Hodgdon Superformance | <<locked>> | 86% | 48,080 psi | 87% | 2979 fps | 97.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,390 psi | 66% | 1893 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 48,269 psi | 87% | 2894 fps | 97.6% |
| IMR 4451 Enduron | <<locked>> | 84% | 48,892 psi | 88% | 2887 fps | 98.1% |
| IMR 4831 | <<locked>> | 88% | 47,456 psi | 86% | 2907 fps | 99.7% |
| Lovex S065 | <<locked>> | 86% | 49,211 psi | 89% | 2890 fps | 99.1% |
| Lovex S070 | <<locked>> | 86% | 47,108 psi | 85% | 2871 fps | 98% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,948 psi | 83% | 2874 fps | 98.4% |
| Norma 204 | <<locked>> | 88% | 48,646 psi | 88% | 2940 fps | 96.4% |
| Norma MRP | <<locked>> | 94% | 47,355 psi | 86% | 3015 fps | 97.9% |
| Norma URP | <<locked>> | 88% | 48,979 psi | 89% | 2953 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 88% | 47,921 psi | 87% | 2946 fps | 98.7% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 47,935 psi | 87% | 2972 fps | 97.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,014 psi | 67% | 1939 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 47,718 psi | 86% | 2986 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 49,734 psi | 90% | 2986 fps | 99.7% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 48,399 psi | 88% | 3012 fps | 99.6% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 44,077 psi | 80% | 2986 fps | 97.4% |
| Rottweil R 903 | <<locked>> | 82% | 47,863 psi | 87% | 2881 fps | 100% |
| Rottweil R 905 | <<locked>> | 94% | 49,530 psi | 90% | 2976 fps | 97.1% |
| Rottweil R 907 | <<locked>> | 84% | 47,616 psi | 86% | 2861 fps | 97.4% |
| Shooters World Long Rifle | <<locked>> | 86% | 49,211 psi | 89% | 2890 fps | 99.1% |
| Shooters World SW4350 | <<locked>> | 86% | 47,108 psi | 85% | 2871 fps | 98% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 48,979 psi | 89% | 2933 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 49,052 psi | 89% | 2779 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 48,588 psi | 88% | 2838 fps | 98.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 49,081 psi | 89% | 2972 fps | 97% |
| Somchem S355 | <<locked>> | 82% | 48,124 psi | 87% | 2877 fps | 100% |
| Somchem S365 | <<locked>> | 90% | 48,196 psi | 87% | 2963 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 47,137 psi | 85% | 2897 fps | 97.3% |
| Vihtavuori N150 | <<locked>> | 84% | 49,139 psi | 89% | 2854 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 47,645 psi | 86% | 2894 fps | 99.6% |
| Vihtavuori N165 | <<locked>> | 98% | 49,530 psi | 90% | 2927 fps | 97.5% |
| Vihtavuori N550 | <<locked>> | 86% | 46,949 psi | 85% | 2897 fps | 99.4% |
| Vihtavuori N555 | <<locked>> | 94% | 47,659 psi | 86% | 2963 fps | 99.9% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 47,021 psi | 85% | 2861 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 48,762 psi | 88% | 2959 fps | 98.2% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,905 psi | 85% | 3107 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 46,688 psi | 84% | 2884 fps | 96.1% |
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 3100 | <<locked>> | 86% | 34,214 psi | 62% | 2618 fps | 95% |
| Accurate 4350 | <<locked>> | 80% | 37,942 psi | 69% | 2726 fps | 98% |
| ADI AR 2208 | <<locked>> | 80% | 46,586 psi | 84% | 2841 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 90% | 44,744 psi | 81% | 2884 fps | 95.5% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 44,759 psi | 81% | 2881 fps | 95.6% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 44,759 psi | 81% | 2881 fps | 95.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,941 psi | 67% | 2740 fps | 98.1% |
| Alliant Reloder-17 | <<locked>> | 80% | 41,901 psi | 76% | 2867 fps | 99.9% |
| Alliant Reloder-19 | <<locked>> | 90% | 44,251 psi | 80% | 2871 fps | 95.5% |
| Alliant Reloder-22 | <<locked>> | 94% | 44,817 psi | 81% | 2930 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,006 psi | 49% | 2470 fps | 95.5% |
| Alliant Reloder-25 | <<locked>> | 92% | 34,925 psi | 63% | 2720 fps | 95.9% |
| Alliant Reloder-26 | 44 gr | 84% | 33,315 psi | 60% | 2717 fps | 96.1% |
| Bofors RP15 | <<locked>> | 96% | 44,193 psi | 80% | 2913 fps | 95.5% |
| Bofors RP5 | <<locked>> | 94% | 44,817 psi | 81% | 2930 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 41,713 psi | 75% | 2740 fps | 95.9% |
| Hodgdon H414 | <<locked>> | 80% | 39,842 psi | 72% | 2772 fps | 95.9% |
| Hodgdon H4350 | <<locked>> | 80% | 42,757 psi | 77% | 2799 fps | 95.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,360 psi | 62% | 2625 fps | 98.6% |
| Hodgdon Retumbo | <<locked>> | 98% | 41,307 psi | 75% | 2923 fps | 95% |
| Hodgdon Superformance | <<locked>> | 80% | 38,783 psi | 70% | 2779 fps | 95.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,137 psi | 49% | 1693 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 39,929 psi | 72% | 2720 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,236 psi | 78% | 2776 fps | 96.8% |
| IMR 4831 | <<locked>> | 80% | 36,376 psi | 66% | 2674 fps | 97.7% |
| Lovex S065 | <<locked>> | 80% | 40,741 psi | 74% | 2723 fps | 97.5% |
| Lovex S070 | <<locked>> | 80% | 38,914 psi | 70% | 2700 fps | 95.8% |
| Lovex S071 | <<locked>> | 92% | 35,418 psi | 64% | 2648 fps | 95.5% |
| Norma 204 | <<locked>> | 86% | 45,469 psi | 82% | 2877 fps | 95.6% |
| Norma MRP | 44.7 gr | 88% | 38,290 psi | 69% | 2812 fps | 95.2% |
| Norma URP | <<locked>> | 80% | 37,521 psi | 68% | 2717 fps | 97.8% |
| Ramshot Hunter | <<locked>> | 80% | 36,405 psi | 66% | 2700 fps | 95.7% |
| Ramshot Magnum | <<locked>> | 96% | 41,524 psi | 75% | 2841 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,760 psi | 50% | 1736 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,527 psi | 81% | 2930 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,550 psi | 68% | 2740 fps | 97.6% |
| ReloadSwiss RS 70 | 41.5 gr | 80% | 36,506 psi | 66% | 2746 fps | 96.9% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 38,261 psi | 69% | 2838 fps | 95% |
| Rottweil R 903 | <<locked>> | 80% | 44,701 psi | 81% | 2822 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 43,439 psi | 79% | 2858 fps | 95.4% |
| Rottweil R 907 | <<locked>> | 80% | 41,713 psi | 75% | 2740 fps | 95.9% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,741 psi | 74% | 2723 fps | 97.5% |
| Shooters World SW4350 | <<locked>> | 80% | 38,914 psi | 70% | 2700 fps | 95.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,847 psi | 83% | 2874 fps | 99.9% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,166 psi | 84% | 2733 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,059 psi | 72% | 2667 fps | 96.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 43,047 psi | 78% | 2851 fps | 95.3% |
| Somchem S355 | <<locked>> | 80% | 45,049 psi | 82% | 2822 fps | 99.9% |
| Somchem S365 | <<locked>> | 80% | 34,200 psi | 62% | 2677 fps | 99.5% |
| Somchem S385 | <<locked>> | 88% | 41,234 psi | 75% | 2779 fps | 95.7% |
| Vihtavuori N150 | <<locked>> | 80% | 42,931 psi | 78% | 2746 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 39,117 psi | 71% | 2723 fps | 98.2% |
| Vihtavuori N165 | <<locked>> | 92% | 40,654 psi | 74% | 2756 fps | 95.1% |
| Vihtavuori N550 | <<locked>> | 80% | 38,479 psi | 70% | 2720 fps | 97.8% |
| Vihtavuori N555 | <<locked>> | 80% | 29,805 psi | 54% | 2552 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,116 psi | 69% | 2687 fps | 99.5% |
| Winchester 760 | <<locked>> | 80% | 39,842 psi | 72% | 2772 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 84% | 27,354 psi | 50% | 2569 fps | 96.6% |
| Winchester Supreme 780 | <<locked>> | 92% | 43,526 psi | 79% | 2822 fps | 95.2% |
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 59 powders for .243 Ackley Improved loaded with the .243 | 100gr | Sierra SP SemiSp. Winchester StaBALL HD delivers the highest muzzle velocity at 3,107 fps; across all powders the maximum-charge window runs from 1,893 fps to 3,107 fps. Alliant Reloder-25 gives the best case fill at 100 %, and 59 of the 59 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (381 MPa), the top charges use 66–90 %, leaving at least 10 % headroom. The 100.0 gr projectile in 0.243" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. Alliant Reloder-25, Hodgdon Retumbo, Hodgdon TrailBoss 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. Norma MRP, ReloadSwiss RS 70, Alliant Reloder-26 rank at the top here: for .243 Ackley Improved with the .243 | 100gr | Sierra SP SemiSp 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.