Load Specifications
Load data in caliber .243 Ackley Improved with .243 | 100gr | Speer Grand Slam 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, ReloadSwiss RS 70 and Norma MRP.
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% | 47,123 psi | 85% | 2890 fps | 98.6% |
| Accurate 4350 | <<locked>> | 88% | 49,153 psi | 89% | 2949 fps | 99.7% |
| ADI AR 2208 | <<locked>> | 82% | 49,226 psi | 89% | 2887 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 92% | 47,152 psi | 85% | 2930 fps | 96.1% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 47,108 psi | 85% | 2927 fps | 96.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 49,806 psi | 90% | 2910 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 50,009 psi | 90% | 3012 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 84% | 47,282 psi | 86% | 2972 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 49,792 psi | 90% | 2979 fps | 96.9% |
| Alliant Reloder-22 | <<locked>> | 96% | 46,963 psi | 85% | 2969 fps | 96.4% |
| Alliant Reloder-23 | <<locked>> | 98% | 47,718 psi | 86% | 2976 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,295 psi | 80% | 2946 fps | 98.8% |
| Alliant Reloder-26 | <<locked>> | 94% | 47,152 psi | 85% | 3041 fps | 99.6% |
| Bofors RP15ᴾ | <<locked>> | 100% | 49,226 psi | 89% | 3012 fps | 96.8% |
| Bofors RP5 | <<locked>> | 96% | 46,963 psi | 85% | 2969 fps | 96.4% |
| Bofors RP7 | <<locked>> | 84% | 46,833 psi | 85% | 2841 fps | 97.1% |
| Hodgdon H414 | <<locked>> | 86% | 47,950 psi | 87% | 2940 fps | 98% |
| Hodgdon H4350 | <<locked>> | 84% | 47,979 psi | 87% | 2900 fps | 96.7% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 47,036 psi | 85% | 2884 fps | 100% |
| Hodgdon Superformance | <<locked>> | 86% | 47,413 psi | 86% | 2963 fps | 97.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,390 psi | 66% | 1890 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 47,834 psi | 87% | 2881 fps | 97.4% |
| IMR 4451 Enduron | <<locked>> | 84% | 48,457 psi | 88% | 2877 fps | 97.9% |
| IMR 4831 | <<locked>> | 90% | 49,879 psi | 90% | 2946 fps | 99.8% |
| Lovex S065 | <<locked>> | 86% | 48,428 psi | 88% | 2874 fps | 99% |
| Lovex S070 | <<locked>> | 88% | 49,458 psi | 90% | 2913 fps | 98.4% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,165 psi | 82% | 2854 fps | 98.2% |
| Norma 204 | <<locked>> | 88% | 47,935 psi | 87% | 2923 fps | 96.2% |
| Norma MRP | <<locked>> | 96% | 49,661 psi | 90% | 3054 fps | 98.3% |
| Norma URP | <<locked>> | 88% | 48,167 psi | 87% | 2936 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 88% | 47,137 psi | 85% | 2930 fps | 98.5% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 46,992 psi | 85% | 2949 fps | 97.1% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,014 psi | 67% | 1932 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 46,833 psi | 85% | 2969 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 48,907 psi | 89% | 2969 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 47,674 psi | 86% | 2995 fps | 99.4% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,294 psi | 78% | 2959 fps | 97% |
| Rottweil R 903 | <<locked>> | 82% | 47,297 psi | 86% | 2867 fps | 100% |
| Rottweil R 905 | <<locked>> | 94% | 48,762 psi | 88% | 2959 fps | 96.8% |
| Rottweil R 907 | <<locked>> | 84% | 46,833 psi | 85% | 2841 fps | 97.1% |
| Shooters World Long Rifle | <<locked>> | 86% | 48,428 psi | 88% | 2874 fps | 99% |
| Shooters World SW4350 | <<locked>> | 88% | 49,458 psi | 90% | 2913 fps | 98.4% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 48,501 psi | 88% | 2923 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 48,501 psi | 88% | 2769 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 47,848 psi | 87% | 2822 fps | 97.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 48,327 psi | 87% | 2953 fps | 96.7% |
| Somchem S355 | <<locked>> | 82% | 47,572 psi | 86% | 2867 fps | 100% |
| Somchem S365 | <<locked>> | 90% | 47,268 psi | 86% | 2943 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 49,705 psi | 90% | 2943 fps | 97.8% |
| Vihtavuori N150 | <<locked>> | 84% | 48,283 psi | 87% | 2838 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 46,833 psi | 85% | 2877 fps | 99.4% |
| Vihtavuori N165 | <<locked>> | 98% | 48,878 psi | 88% | 2913 fps | 97.2% |
| Vihtavuori N550 | <<locked>> | 88% | 49,342 psi | 89% | 2936 fps | 99.6% |
| Vihtavuori N555 | <<locked>> | 96% | 49,879 psi | 90% | 2999 fps | 100% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 49,516 psi | 90% | 2900 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 48,312 psi | 87% | 2946 fps | 98% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 45,934 psi | 83% | 3084 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 49,385 psi | 89% | 2930 fps | 96.7% |
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% | 35,998 psi | 65% | 2657 fps | 95.6% |
| Accurate 4350 | <<locked>> | 80% | 37,391 psi | 68% | 2713 fps | 97.8% |
| ADI AR 2208 | <<locked>> | 80% | 46,050 psi | 83% | 2828 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 90% | 44,019 psi | 80% | 2864 fps | 95.2% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 44,367 psi | 80% | 2867 fps | 95.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 46,557 psi | 84% | 2854 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,201 psi | 66% | 2717 fps | 97.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 41,089 psi | 74% | 2851 fps | 99.8% |
| Alliant Reloder-19 | <<locked>> | 90% | 43,845 psi | 79% | 2861 fps | 95.3% |
| Alliant Reloder-22 | <<locked>> | 94% | 44,121 psi | 80% | 2910 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 26,614 psi | 48% | 2457 fps | 95.1% |
| Alliant Reloder-25 | <<locked>> | 92% | 34,360 psi | 62% | 2700 fps | 95.5% |
| Alliant Reloder-26 | 43.4 gr | 84% | 32,721 psi | 59% | 2700 fps | 95.7% |
| Bofors RP15 | <<locked>> | 96% | 43,221 psi | 78% | 2890 fps | 95.1% |
| Bofors RP5 | <<locked>> | 94% | 44,121 psi | 80% | 2910 fps | 95.5% |
| Bofors RP7 | <<locked>> | 80% | 41,234 psi | 75% | 2726 fps | 95.6% |
| Hodgdon H414 | <<locked>> | 80% | 39,334 psi | 71% | 2759 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 80% | 42,250 psi | 76% | 2782 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 33,852 psi | 61% | 2608 fps | 98.4% |
| Hodgdon Superformance | <<locked>> | 82% | 41,104 psi | 74% | 2831 fps | 95.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,282 psi | 49% | 1693 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 39,450 psi | 71% | 2707 fps | 95% |
| IMR 4451 Enduron | <<locked>> | 80% | 42,743 psi | 77% | 2762 fps | 96.6% |
| IMR 4831 | <<locked>> | 80% | 35,839 psi | 65% | 2661 fps | 97.4% |
| Lovex S065 | <<locked>> | 80% | 40,234 psi | 73% | 2710 fps | 97.3% |
| Lovex S070 | <<locked>> | 80% | 38,450 psi | 70% | 2684 fps | 95.6% |
| Lovex S071 | <<locked>> | 92% | 34,708 psi | 63% | 2628 fps | 95.1% |
| Norma 204 | <<locked>> | 86% | 44,759 psi | 81% | 2858 fps | 95.3% |
| Norma MRP | 45.1 gr | 90% | 40,350 psi | 73% | 2861 fps | 95.9% |
| Norma URP | <<locked>> | 80% | 36,970 psi | 67% | 2703 fps | 97.6% |
| Ramshot Hunter | <<locked>> | 80% | 35,940 psi | 65% | 2687 fps | 95.4% |
| Ramshot Magnum | <<locked>> | 96% | 40,698 psi | 74% | 2815 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,659 psi | 50% | 1729 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 43,671 psi | 79% | 2910 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,043 psi | 67% | 2726 fps | 97.4% |
| ReloadSwiss RS 70 | 41 gr | 80% | 36,100 psi | 65% | 2730 fps | 96.6% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 40,422 psi | 73% | 2890 fps | 95.8% |
| Rottweil R 903 | <<locked>> | 80% | 44,121 psi | 80% | 2808 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 90% | 42,699 psi | 77% | 2838 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 41,234 psi | 75% | 2726 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,234 psi | 73% | 2710 fps | 97.3% |
| Shooters World SW4350 | <<locked>> | 80% | 38,450 psi | 70% | 2684 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,324 psi | 82% | 2864 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 45,629 psi | 83% | 2720 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 39,349 psi | 71% | 2648 fps | 95.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 42,308 psi | 77% | 2831 fps | 95% |
| Somchem S355 | <<locked>> | 80% | 44,498 psi | 81% | 2808 fps | 99.9% |
| Somchem S365 | <<locked>> | 80% | 33,431 psi | 60% | 2657 fps | 99.3% |
| Somchem S385 | <<locked>> | 88% | 40,828 psi | 74% | 2766 fps | 95.5% |
| Vihtavuori N150 | <<locked>> | 80% | 42,424 psi | 77% | 2733 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 38,595 psi | 70% | 2707 fps | 98% |
| Vihtavuori N165 | <<locked>> | 94% | 42,830 psi | 78% | 2799 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 38,000 psi | 69% | 2707 fps | 97.6% |
| Vihtavuori N555 | <<locked>> | 80% | 29,298 psi | 53% | 2536 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 37,724 psi | 68% | 2677 fps | 99.5% |
| Winchester 760 | <<locked>> | 80% | 39,334 psi | 71% | 2759 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 84% | 26,847 psi | 49% | 2546 fps | 96.1% |
| Winchester Supreme 780 | <<locked>> | 94% | 46,021 psi | 83% | 2867 fps | 95.8% |
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 | Speer Grand Slam. Winchester StaBALL HD delivers the highest muzzle velocity at 3,084 fps; across all powders the maximum-charge window runs from 1,890 fps to 3,084 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 1:10.5 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, ReloadSwiss RS 70, Norma MRP rank at the top here: for .243 Ackley Improved with the .243 | 100gr | Speer Grand Slam 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.