Load Specifications
Load data in caliber .243 Ackley Improved with .243 | 100gr | Winchester SPBT bullet and 58 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, Norma MRP 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.
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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 96% | 47,964 psi | 87% | 2907 fps | 98.8% |
| Accurate 4350 | <<locked>> | 88% | 49,734 psi | 90% | 2963 fps | 99.8% |
| ADI AR 2208 | <<locked>> | 82% | 49,472 psi | 90% | 2890 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 92% | 47,630 psi | 86% | 2943 fps | 96.3% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 47,601 psi | 86% | 2936 fps | 96.3% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 47,601 psi | 86% | 2936 fps | 96.3% |
| Alliant Reloder-16 | <<locked>> | 88% | 47,558 psi | 86% | 2969 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 84% | 47,819 psi | 87% | 2986 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 92% | 47,021 psi | 85% | 2930 fps | 96.3% |
| Alliant Reloder-22 | <<locked>> | 96% | 47,776 psi | 86% | 2989 fps | 96.6% |
| Alliant Reloder-23 | <<locked>> | 98% | 48,211 psi | 87% | 2986 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,701 psi | 81% | 2956 fps | 99% |
| Alliant Reloder-26 | <<locked>> | 94% | 47,674 psi | 86% | 3054 fps | 99.7% |
| Bofors RP15ᴾ | <<locked>> | 100% | 50,009 psi | 90% | 3028 fps | 97% |
| Bofors RP5 | <<locked>> | 96% | 47,776 psi | 86% | 2989 fps | 96.6% |
| Bofors RP7 | <<locked>> | 84% | 47,340 psi | 86% | 2854 fps | 97.3% |
| Hodgdon H414 | <<locked>> | 86% | 48,515 psi | 88% | 2953 fps | 98.1% |
| Hodgdon H4350 | <<locked>> | 84% | 48,501 psi | 88% | 2913 fps | 96.9% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 47,587 psi | 86% | 2894 fps | 100% |
| Hodgdon Superformance | <<locked>> | 86% | 47,863 psi | 87% | 2976 fps | 97.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,289 psi | 66% | 1890 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 48,008 psi | 87% | 2887 fps | 97.5% |
| IMR 4451 Enduron | <<locked>> | 84% | 48,660 psi | 88% | 2881 fps | 98% |
| IMR 4831 | <<locked>> | 88% | 47,152 psi | 85% | 2900 fps | 99.6% |
| Lovex S065 | <<locked>> | 86% | 48,936 psi | 89% | 2887 fps | 99.1% |
| Lovex S070 | <<locked>> | 88% | 49,995 psi | 90% | 2927 fps | 98.5% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,643 psi | 83% | 2867 fps | 98.4% |
| Norma 204 | <<locked>> | 88% | 48,443 psi | 88% | 2933 fps | 96.4% |
| Norma MRP | <<locked>> | 94% | 47,108 psi | 85% | 3009 fps | 97.9% |
| Norma URP | <<locked>> | 88% | 48,747 psi | 88% | 2949 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 88% | 47,659 psi | 86% | 2943 fps | 98.7% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 47,732 psi | 86% | 2966 fps | 97.3% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,231 psi | 67% | 1939 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 47,398 psi | 86% | 2979 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 49,458 psi | 90% | 2982 fps | 99.7% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 48,153 psi | 87% | 3005 fps | 99.5% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,874 psi | 79% | 2979 fps | 97.3% |
| Rottweil R 903 | <<locked>> | 82% | 47,572 psi | 86% | 2874 fps | 100% |
| Rottweil R 905 | <<locked>> | 94% | 49,269 psi | 89% | 2969 fps | 97% |
| Rottweil R 907 | <<locked>> | 84% | 47,340 psi | 86% | 2854 fps | 97.3% |
| Shooters World Long Rifle | <<locked>> | 86% | 48,936 psi | 89% | 2887 fps | 99.1% |
| Shooters World SW4350 | <<locked>> | 88% | 49,995 psi | 90% | 2927 fps | 98.5% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 49,037 psi | 89% | 2933 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 48,791 psi | 88% | 2772 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 48,385 psi | 88% | 2835 fps | 98.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 48,834 psi | 88% | 2966 fps | 96.9% |
| Somchem S355 | <<locked>> | 82% | 47,834 psi | 87% | 2871 fps | 100% |
| Somchem S365 | <<locked>> | 90% | 47,892 psi | 87% | 2956 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 46,891 psi | 85% | 2894 fps | 97.2% |
| Vihtavuori N150 | <<locked>> | 84% | 48,878 psi | 88% | 2851 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 47,398 psi | 86% | 2887 fps | 99.5% |
| Vihtavuori N165 | <<locked>> | 98% | 49,298 psi | 89% | 2923 fps | 97.4% |
| Vihtavuori N550 | <<locked>> | 88% | 49,879 psi | 90% | 2949 fps | 99.7% |
| Vihtavuori N555 | <<locked>> | 94% | 47,369 psi | 86% | 2956 fps | 99.8% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 49,966 psi | 90% | 2910 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 48,515 psi | 88% | 2953 fps | 98.1% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,688 psi | 84% | 3104 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 49,864 psi | 90% | 2940 fps | 96.9% |
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 3100 | <<locked>> | 88% | 36,463 psi | 66% | 2674 fps | 95.9% |
| Accurate 4350 | <<locked>> | 80% | 37,681 psi | 68% | 2720 fps | 97.9% |
| ADI AR 2208 | <<locked>> | 80% | 46,615 psi | 84% | 2838 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 90% | 44,498 psi | 81% | 2877 fps | 95.4% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 44,527 psi | 81% | 2874 fps | 95.5% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 44,527 psi | 81% | 2874 fps | 95.5% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,724 psi | 66% | 2730 fps | 98% |
| Alliant Reloder-17 | <<locked>> | 80% | 41,655 psi | 75% | 2864 fps | 99.9% |
| Alliant Reloder-19 | <<locked>> | 90% | 44,005 psi | 80% | 2867 fps | 95.4% |
| Alliant Reloder-22 | <<locked>> | 94% | 44,599 psi | 81% | 2923 fps | 95.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,021 psi | 49% | 2470 fps | 95.5% |
| Alliant Reloder-25 | <<locked>> | 92% | 34,737 psi | 63% | 2713 fps | 95.8% |
| Alliant Reloder-26 | 43.8 gr | 84% | 33,098 psi | 60% | 2713 fps | 96% |
| Bofors RP15 | <<locked>> | 96% | 43,656 psi | 79% | 2904 fps | 95.3% |
| Bofors RP5 | <<locked>> | 94% | 44,599 psi | 81% | 2923 fps | 95.7% |
| Bofors RP7 | <<locked>> | 80% | 41,742 psi | 76% | 2740 fps | 95.8% |
| Hodgdon H414 | <<locked>> | 80% | 39,566 psi | 72% | 2766 fps | 95.8% |
| Hodgdon H4350 | <<locked>> | 80% | 42,482 psi | 77% | 2789 fps | 95.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,127 psi | 62% | 2618 fps | 98.5% |
| Hodgdon Superformance | <<locked>> | 80% | 38,580 psi | 70% | 2772 fps | 95% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,282 psi | 49% | 1693 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 39,653 psi | 72% | 2713 fps | 95.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 42,975 psi | 78% | 2769 fps | 96.7% |
| IMR 4831 | <<locked>> | 80% | 36,085 psi | 65% | 2667 fps | 97.6% |
| Lovex S065 | <<locked>> | 80% | 40,727 psi | 74% | 2720 fps | 97.5% |
| Lovex S070 | <<locked>> | 80% | 38,928 psi | 70% | 2697 fps | 95.8% |
| Lovex S071 | <<locked>> | 92% | 35,201 psi | 64% | 2641 fps | 95.4% |
| Norma 204 | <<locked>> | 86% | 45,223 psi | 82% | 2871 fps | 95.5% |
| Norma MRP | 44.5 gr | 88% | 38,072 psi | 69% | 2805 fps | 95% |
| Norma URP | <<locked>> | 80% | 37,521 psi | 68% | 2717 fps | 97.8% |
| Ramshot Hunter | <<locked>> | 80% | 36,419 psi | 66% | 2700 fps | 95.7% |
| Ramshot Magnum | <<locked>> | 96% | 41,075 psi | 74% | 2828 fps | 95.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,644 psi | 50% | 1732 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,237 psi | 80% | 2920 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,565 psi | 68% | 2740 fps | 97.6% |
| ReloadSwiss RS 70 | 41.3 gr | 80% | 36,289 psi | 66% | 2740 fps | 96.8% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 40,741 psi | 74% | 2900 fps | 96.1% |
| Rottweil R 903 | <<locked>> | 80% | 44,744 psi | 81% | 2822 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 43,178 psi | 78% | 2851 fps | 95.3% |
| Rottweil R 907 | <<locked>> | 80% | 41,742 psi | 76% | 2740 fps | 95.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,727 psi | 74% | 2720 fps | 97.5% |
| Shooters World SW4350 | <<locked>> | 80% | 38,928 psi | 70% | 2697 fps | 95.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,861 psi | 83% | 2877 fps | 99.9% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 45,890 psi | 83% | 2726 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 39,842 psi | 72% | 2661 fps | 96% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 42,772 psi | 77% | 2844 fps | 95.2% |
| Somchem S355 | <<locked>> | 80% | 45,049 psi | 82% | 2822 fps | 99.9% |
| Somchem S365 | <<locked>> | 80% | 33,968 psi | 61% | 2671 fps | 99.5% |
| Somchem S385 | <<locked>> | 88% | 41,046 psi | 74% | 2772 fps | 95.6% |
| Vihtavuori N150 | <<locked>> | 80% | 42,975 psi | 78% | 2746 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 38,841 psi | 70% | 2717 fps | 98.1% |
| Vihtavuori N165 | <<locked>> | 92% | 40,437 psi | 73% | 2749 fps | 95% |
| Vihtavuori N550 | <<locked>> | 80% | 38,247 psi | 69% | 2713 fps | 97.8% |
| Vihtavuori N555 | <<locked>> | 80% | 29,559 psi | 53% | 2546 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 37,898 psi | 69% | 2680 fps | 99.5% |
| Winchester 760 | <<locked>> | 80% | 39,566 psi | 72% | 2766 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 84% | 27,195 psi | 49% | 2562 fps | 96.4% |
| Winchester Supreme 780 | <<locked>> | 92% | 43,308 psi | 78% | 2815 fps | 95.1% |
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 58 powders for .243 Ackley Improved loaded with the .243 | 100gr | Winchester SPBT. Winchester StaBALL HD delivers the highest muzzle velocity at 3,104 fps; across all powders the maximum-charge window runs from 1,890 fps to 3,104 fps. Alliant Reloder-25 gives the best case fill at 100 %, and 58 of the 58 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 1:11.0 twist; slower twists will usually not stabilise this weight. Alliant Reloder-25, Bofors RP15, 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. Alliant Reloder-26, Norma MRP, ReloadSwiss RS 70 rank at the top here: for .243 Ackley Improved with the .243 | 100gr | Winchester SPBT 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.