Load Specifications
Load data in caliber .243 Ackley Improved with .243 | 105gr | Lapua Naturalis bullet and 62 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, Alliant Reloder-16 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 2495 | <<locked>> | 82% | 49,313 psi | 89% | 2972 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 48,283 psi | 87% | 2966 fps | 96.1% |
| Accurate 3100ᴾ | <<locked>> | 100% | 48,080 psi | 87% | 3048 fps | 97.9% |
| Accurate 4064 | <<locked>> | 84% | 49,966 psi | 90% | 3028 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 46,963 psi | 85% | 3054 fps | 98.9% |
| ADI AR 2208 | <<locked>> | 84% | 48,138 psi | 87% | 3009 fps | 99.4% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 49,676 psi | 90% | 3176 fps | 99.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 48,196 psi | 87% | 3031 fps | 99.9% |
| Alliant Reloder-15 | <<locked>> | 82% | 48,443 psi | 88% | 3048 fps | 99.5% |
| Alliant Reloder-16 | <<locked>> | 92% | 48,501 psi | 88% | 3130 fps | 99.5% |
| Alliant Reloder-17 | <<locked>> | 88% | 49,139 psi | 89% | 3156 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 45,469 psi | 82% | 3077 fps | 99.8% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 39,537 psi | 72% | 2956 fps | 96.2% |
| Alliant Reloder-26 | <<locked>> | 98% | 48,211 psi | 87% | 3202 fps | 99.2% |
| Bofors RP3 | <<locked>> | 84% | 48,428 psi | 88% | 3041 fps | 100% |
| Bofors RP7 | <<locked>> | 88% | 48,602 psi | 88% | 3012 fps | 96.4% |
| Hodgdon H380 | <<locked>> | 84% | 48,994 psi | 89% | 3048 fps | 98.9% |
| Hodgdon H414 | <<locked>> | 90% | 49,603 psi | 90% | 3110 fps | 97.3% |
| Hodgdon H4350 | <<locked>> | 88% | 49,995 psi | 90% | 3074 fps | 96% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 48,283 psi | 87% | 3051 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 90% | 49,545 psi | 90% | 3140 fps | 97% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,781 psi | 65% | 1982 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 47,268 psi | 86% | 2986 fps | 99.4% |
| IMR 4350 | <<locked>> | 92% | 49,429 psi | 89% | 3045 fps | 96.7% |
| IMR 4451 Enduron | <<locked>> | 86% | 47,268 psi | 86% | 2989 fps | 96.6% |
| IMR 4831 | <<locked>> | 92% | 47,674 psi | 86% | 3051 fps | 99.1% |
| IMR 4895 | <<locked>> | 82% | 49,705 psi | 90% | 3081 fps | 99.8% |
| Lovex S062 | <<locked>> | 82% | 47,282 psi | 86% | 2986 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 47,152 psi | 85% | 2986 fps | 97.9% |
| Lovex S070 | <<locked>> | 90% | 47,993 psi | 87% | 3022 fps | 97.1% |
| Norma 203B | <<locked>> | 82% | 47,776 psi | 86% | 3035 fps | 99.7% |
| Norma MRP | <<locked>> | 98% | 47,659 psi | 86% | 3153 fps | 96.8% |
| Norma URP | <<locked>> | 92% | 49,792 psi | 90% | 3110 fps | 99.3% |
| Ramshot Big Game | <<locked>> | 82% | 48,167 psi | 87% | 3054 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 92% | 48,573 psi | 88% | 3097 fps | 97.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,260 psi | 66% | 2028 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 49,385 psi | 89% | 3031 fps | 97.7% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 48,805 psi | 88% | 3156 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 47,021 psi | 85% | 3077 fps | 98.8% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 49,255 psi | 89% | 3159 fps | 99% |
| Rottweil R 902 | <<locked>> | 82% | 49,298 psi | 89% | 3002 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 48,617 psi | 88% | 3038 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 88% | 48,602 psi | 88% | 3012 fps | 96.4% |
| Shooters World Long Rifle | <<locked>> | 88% | 47,152 psi | 85% | 2986 fps | 97.9% |
| Shooters World Precision | <<locked>> | 82% | 47,282 psi | 86% | 2986 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 47,993 psi | 87% | 3022 fps | 97.1% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 47,007 psi | 85% | 3041 fps | 99.6% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 47,529 psi | 86% | 2897 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 46,673 psi | 84% | 2930 fps | 96.6% |
| Somchem S355 | <<locked>> | 86% | 48,820 psi | 88% | 3035 fps | 99.9% |
| Somchem S365 | <<locked>> | 94% | 48,428 psi | 88% | 3117 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 47,659 psi | 86% | 3038 fps | 96.2% |
| Vihtavuori N135 | <<locked>> | 82% | 49,095 psi | 89% | 2969 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 49,937 psi | 90% | 2986 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 47,007 psi | 85% | 2963 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 48,559 psi | 88% | 3048 fps | 99.1% |
| Vihtavuori N540 | <<locked>> | 82% | 48,225 psi | 87% | 2976 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 47,616 psi | 86% | 3045 fps | 98.8% |
| Vihtavuori N555 | <<locked>> | 98% | 47,253 psi | 86% | 3097 fps | 99.4% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 48,283 psi | 87% | 3018 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 49,908 psi | 90% | 3117 fps | 97.4% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 40,828 psi | 74% | 3104 fps | 100% |
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% | 46,253 psi | 84% | 2923 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 45,150 psi | 82% | 2904 fps | 95.2% |
| Accurate 3100 | <<locked>> | 94% | 38,783 psi | 70% | 2854 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 43,787 psi | 79% | 2920 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 35,172 psi | 64% | 2792 fps | 95.9% |
| ADI AR 2208 | <<locked>> | 80% | 42,293 psi | 77% | 2890 fps | 98.5% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 46,325 psi | 84% | 3110 fps | 99.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 42,293 psi | 77% | 2913 fps | 99.5% |
| Alliant Reloder-15 | <<locked>> | 80% | 45,252 psi | 82% | 2986 fps | 99.1% |
| Alliant Reloder-16 | 37.7 gr | 80% | 32,663 psi | 59% | 2743 fps | 95% |
| Alliant Reloder-17 | <<locked>> | 80% | 36,825 psi | 67% | 2884 fps | 98.4% |
| Alliant Reloder-23 | <<locked>> | 88% | 30,603 psi | 55% | 2703 fps | 95.9% |
| Alliant Reloder-25 | <<locked>> | 98% | 37,231 psi | 67% | 2897 fps | 95.2% |
| Alliant Reloder-26 | 46.8 gr | 90% | 35,636 psi | 64% | 2904 fps | 95.6% |
| Bofors RP3 | <<locked>> | 80% | 42,061 psi | 76% | 2917 fps | 99.5% |
| Bofors RP7 | <<locked>> | 86% | 45,730 psi | 83% | 2953 fps | 95.7% |
| Hodgdon H380 | <<locked>> | 80% | 42,960 psi | 78% | 2927 fps | 97.7% |
| Hodgdon H414 | <<locked>> | 86% | 43,178 psi | 78% | 2979 fps | 95.6% |
| Hodgdon H4350 | <<locked>> | 86% | 46,760 psi | 85% | 3012 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 30,168 psi | 55% | 2635 fps | 95.9% |
| Hodgdon Superformance | <<locked>> | 86% | 42,873 psi | 78% | 2999 fps | 95% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,513 psi | 48% | 1772 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 44,425 psi | 80% | 2930 fps | 99% |
| IMR 4350 | <<locked>> | 88% | 43,540 psi | 79% | 2927 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 84% | 44,541 psi | 81% | 2933 fps | 95.9% |
| IMR 4831 | <<locked>> | 82% | 33,939 psi | 61% | 2743 fps | 95.5% |
| IMR 4895 | <<locked>> | 80% | 46,427 psi | 84% | 3018 fps | 99.5% |
| Lovex S062 | <<locked>> | 80% | 44,469 psi | 80% | 2930 fps | 99.8% |
| Lovex S065 | <<locked>> | 82% | 38,783 psi | 70% | 2808 fps | 95.7% |
| Lovex S070 | <<locked>> | 86% | 42,192 psi | 76% | 2904 fps | 95.6% |
| Norma 203B | <<locked>> | 80% | 44,585 psi | 81% | 2969 fps | 99.3% |
| Norma MRP | <<locked>> | 96% | 44,425 psi | 80% | 3084 fps | 95.9% |
| Norma URP | <<locked>> | 82% | 35,447 psi | 64% | 2799 fps | 95.9% |
| Ramshot Big Game | <<locked>> | 80% | 44,991 psi | 81% | 2995 fps | 99.3% |
| Ramshot Hunter | <<locked>> | 86% | 39,523 psi | 72% | 2904 fps | 95.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,021 psi | 49% | 1814 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 43,221 psi | 78% | 2907 fps | 96.3% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 39,218 psi | 71% | 2959 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 35,070 psi | 63% | 2808 fps | 95.5% |
| ReloadSwiss RS 70 | 43.3 gr | 84% | 37,130 psi | 67% | 2881 fps | 95.6% |
| Rottweil R 902 | <<locked>> | 80% | 46,035 psi | 83% | 2943 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 80% | 39,610 psi | 72% | 2854 fps | 99% |
| Rottweil R 907 | <<locked>> | 86% | 45,730 psi | 83% | 2953 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 82% | 38,783 psi | 70% | 2808 fps | 95.7% |
| Shooters World Precision | <<locked>> | 80% | 44,469 psi | 80% | 2930 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 86% | 42,192 psi | 76% | 2904 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 40,973 psi | 74% | 2917 fps | 98.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 41,611 psi | 75% | 2789 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 40,959 psi | 74% | 2812 fps | 95% |
| Somchem S355 | <<locked>> | 80% | 40,306 psi | 73% | 2861 fps | 98.9% |
| Somchem S365 | <<locked>> | 80% | 29,501 psi | 53% | 2674 fps | 97.1% |
| Somchem S385 | <<locked>> | 94% | 44,469 psi | 80% | 2976 fps | 95.3% |
| Vihtavuori N135 | <<locked>> | 80% | 46,079 psi | 83% | 2920 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 46,630 psi | 84% | 2930 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 38,392 psi | 69% | 2789 fps | 99.4% |
| Vihtavuori N160 | <<locked>> | 80% | 34,345 psi | 62% | 2733 fps | 95.4% |
| Vihtavuori N540 | <<locked>> | 80% | 45,121 psi | 82% | 2920 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 33,982 psi | 61% | 2736 fps | 95% |
| Vihtavuori N555 | <<locked>> | 88% | 33,591 psi | 61% | 2789 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 34,084 psi | 62% | 2710 fps | 97.8% |
| Winchester 760 | <<locked>> | 86% | 43,482 psi | 79% | 2986 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 90% | 28,906 psi | 52% | 2726 fps | 95.6% |
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 62 powders for .243 Ackley Improved loaded with the .243 | 105gr | Lapua Naturalis. Alliant Reloder-26 delivers the highest muzzle velocity at 3,202 fps; across all powders the maximum-charge window runs from 1,982 fps to 3,202 fps. Accurate 3100 gives the best case fill at 100 %, and 62 of the 62 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (381 MPa), the top charges use 65–90 %, leaving at least 10 % headroom. The 90.0 gr projectile in 0.243" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-23, Alliant Reloder-25 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, Alliant Reloder-16, ReloadSwiss RS 70 rank at the top here: for .243 Ackley Improved with the .243 | 105gr | Lapua Naturalis 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.