Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 250gr | Barnes X S bullet and 72 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ReloadSwiss RS 76 and Vihtavuori N570.
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: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 90% | 62,671 psi | 90% | 2861 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 45,150 psi | 65% | 2717 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 90% | 61,931 psi | 89% | 2989 fps | 99.8% |
| ADI APS 450 | <<locked>> | 82% | 61,380 psi | 88% | 2218 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 62,787 psi | 90% | 2940 fps | 100% |
| ADI AR 2213 | <<locked>> | 90% | 61,322 psi | 88% | 2966 fps | 100% |
| ADI AR 2217 | <<locked>> | 98% | 59,886 psi | 86% | 2940 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 56,217 psi | 81% | 3012 fps | 99.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 58,566 psi | 84% | 2966 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 59,321 psi | 85% | 2867 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 62,236 psi | 89% | 2927 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 90% | 61,975 psi | 89% | 2959 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 60,060 psi | 86% | 2858 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 60,046 psi | 86% | 2933 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 61,250 psi | 88% | 2959 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 62,265 psi | 89% | 3058 fps | 99.5% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 54,360 psi | 78% | 2936 fps | 98.2% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 61,046 psi | 88% | 2917 fps | 99.4% |
| Bofors RP15 | <<locked>> | 92% | 61,105 psi | 88% | 2946 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 60,060 psi | 86% | 2963 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 61,975 psi | 89% | 2959 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 62,874 psi | 90% | 2861 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 61,525 psi | 88% | 2959 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 60,104 psi | 86% | 2861 fps | 100% |
| Hodgdon H4831 | <<locked>> | 92% | 60,176 psi | 86% | 2894 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 88% | 59,292 psi | 85% | 2881 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 59,683 psi | 86% | 2785 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 59,074 psi | 85% | 3028 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,058 psi | 55% | 1785 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 61,206 psi | 88% | 2851 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 60,539 psi | 87% | 2828 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 60,423 psi | 87% | 2867 fps | 100% |
| IMR 7828 SSC | <<locked>> | 88% | 59,596 psi | 86% | 2949 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 62,671 psi | 90% | 2871 fps | 97% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 54,273 psi | 78% | 2904 fps | 100% |
| Lovex S065 | <<locked>> | 82% | 61,714 psi | 89% | 2825 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 60,205 psi | 86% | 2831 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 60,568 psi | 87% | 2835 fps | 100% |
| Norma 204 | <<locked>> | 84% | 62,903 psi | 90% | 2920 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 55,419 psi | 80% | 2923 fps | 100% |
| Norma MRP | <<locked>> | 88% | 62,337 psi | 90% | 2976 fps | 100% |
| Norma URP | <<locked>> | 82% | 60,191 psi | 86% | 2844 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 60,104 psi | 86% | 2956 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 62,932 psi | 90% | 2910 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 61,511 psi | 88% | 2923 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,088 psi | 56% | 1827 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 62,830 psi | 90% | 2894 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 60,988 psi | 88% | 2923 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 60,031 psi | 86% | 3018 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 59,712 psi | 86% | 2999 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 59,422 psi | 85% | 2854 fps | 100% |
| Rottweil R 905 | <<locked>> | 88% | 62,410 psi | 90% | 2923 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 62,874 psi | 90% | 2861 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 61,714 psi | 89% | 2825 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 60,205 psi | 86% | 2831 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 47,456 psi | 68% | 2736 fps | 96.2% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 60,553 psi | 87% | 2782 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 61,989 psi | 89% | 2920 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 61,177 psi | 88% | 2851 fps | 100% |
| Somchem S365 | <<locked>> | 84% | 62,076 psi | 89% | 2848 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 62,932 psi | 90% | 2890 fps | 100% |
| Vihtavuori N150 | <<locked>> | 84% | 62,613 psi | 90% | 2769 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 60,655 psi | 87% | 2851 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 59,524 psi | 86% | 2884 fps | 98% |
| Vihtavuori N555 | <<locked>> | 88% | 62,540 psi | 90% | 2887 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 62,163 psi | 89% | 2995 fps | 100% |
| Vihtavuori N565 | <<locked>> | 94% | 62,671 psi | 90% | 2976 fps | 100% |
| Vihtavuori N568 | <<locked>> | 96% | 60,133 psi | 86% | 2995 fps | 99.9% |
| Vihtavuori N570 | <<locked>> | 98% | 61,772 psi | 89% | 3061 fps | 99.3% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 60,901 psi | 87% | 2782 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 60,423 psi | 87% | 2959 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 59,872 psi | 86% | 2854 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 45,890 psi | 66% | 2621 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 42,337 psi | 61% | 2661 fps | 95% |
| Accurate MAGPRO | <<locked>> | 80% | 44,498 psi | 64% | 2700 fps | 97.6% |
| ADI APS 450 | <<locked>> | 80% | 59,437 psi | 85% | 2192 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 48,863 psi | 70% | 2733 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 44,179 psi | 63% | 2687 fps | 98.9% |
| ADI AR 2217 | <<locked>> | 80% | 33,736 psi | 48% | 2457 fps | 96.4% |
| ADI AR 2218 | <<locked>> | 92% | 42,815 psi | 62% | 2746 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 31,270 psi | 45% | 2441 fps | 98.5% |
| Alliant Reloder-16 | <<locked>> | 80% | 55,796 psi | 80% | 2818 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 48,733 psi | 70% | 2726 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 45,237 psi | 65% | 2697 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,034 psi | 63% | 2628 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,421 psi | 55% | 2589 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 49,792 psi | 72% | 2799 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 41,075 psi | 59% | 2694 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 92% | 41,292 psi | 59% | 2694 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 42,554 psi | 61% | 2598 fps | 95.9% |
| Bofors RP15 | <<locked>> | 80% | 42,308 psi | 61% | 2641 fps | 99.3% |
| Bofors RP30 | <<locked>> | 80% | 36,230 psi | 52% | 2539 fps | 97.5% |
| Bofors RP5 | <<locked>> | 80% | 45,237 psi | 65% | 2697 fps | 99.7% |
| Bofors RP7 | <<locked>> | 80% | 59,146 psi | 85% | 2812 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 34,548 psi | 50% | 2477 fps | 97.4% |
| Hodgdon H4350 | <<locked>> | 80% | 56,492 psi | 81% | 2808 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 41,655 psi | 60% | 2582 fps | 97.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 45,977 psi | 66% | 2667 fps | 98.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 52,852 psi | 76% | 2697 fps | 100% |
| Hodgdon Retumbo | 87.5 gr | 80% | 37,565 psi | 54% | 2641 fps | 99.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,601 psi | 41% | 1594 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 54,360 psi | 78% | 2756 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 50,691 psi | 73% | 2694 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,601 psi | 68% | 2667 fps | 99% |
| IMR 7828 SSC | <<locked>> | 80% | 45,672 psi | 66% | 2723 fps | 99.2% |
| IMR 7977 Enduron | <<locked>> | 92% | 55,419 psi | 80% | 2762 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 82% | 30,980 psi | 45% | 2428 fps | 95.3% |
| Lovex S065 | <<locked>> | 80% | 58,160 psi | 84% | 2779 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 56,869 psi | 82% | 2785 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 40,118 psi | 58% | 2513 fps | 99.9% |
| Norma 204 | <<locked>> | 80% | 55,332 psi | 79% | 2815 fps | 100% |
| Norma 217 | <<locked>> | 80% | 29,370 psi | 42% | 2405 fps | 97.1% |
| Norma MRP | <<locked>> | 80% | 47,848 psi | 69% | 2762 fps | 100% |
| Norma URP | <<locked>> | 80% | 56,724 psi | 81% | 2802 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 48,385 psi | 70% | 2782 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 80% | 55,550 psi | 80% | 2812 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 42,975 psi | 62% | 2648 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,457 psi | 42% | 1634 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 58,900 psi | 85% | 2844 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 57,029 psi | 82% | 2871 fps | 100% |
| ReloadSwiss RS 76 | 93.7 gr | 80% | 36,985 psi | 53% | 2621 fps | 99.8% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 34,113 psi | 49% | 2523 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 49,588 psi | 71% | 2703 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 80% | 48,689 psi | 70% | 2720 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 80% | 59,146 psi | 85% | 2812 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 58,160 psi | 84% | 2779 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 56,869 psi | 82% | 2785 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 44,396 psi | 64% | 2680 fps | 95.3% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 56,985 psi | 82% | 2736 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 48,341 psi | 69% | 2717 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 50,589 psi | 73% | 2694 fps | 99.3% |
| Somchem S365 | <<locked>> | 80% | 54,853 psi | 79% | 2759 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,269 psi | 71% | 2697 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 55,782 psi | 80% | 2684 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 42,061 psi | 60% | 2562 fps | 99.5% |
| Vihtavuori N170 | <<locked>> | 92% | 46,891 psi | 67% | 2677 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 80% | 49,052 psi | 70% | 2703 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 45,223 psi | 65% | 2720 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 80% | 40,364 psi | 58% | 2605 fps | 97.9% |
| Vihtavuori N568 | <<locked>> | 80% | 35,273 psi | 51% | 2536 fps | 95% |
| Vihtavuori N570 | 98.6 gr | 86% | 41,162 psi | 59% | 2700 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 57,145 psi | 82% | 2736 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 42,496 psi | 61% | 2703 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 49,139 psi | 71% | 2697 fps | 99.9% |
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 79 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 250gr | Barnes X S. Vihtavuori N570 delivers the highest muzzle velocity at 3,061 fps; across all powders the maximum-charge window runs from 1,785 fps to 3,061 fps. Accurate 8700 gives the best case fill at 100 %, and 79 of the 79 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (480 MPa), the top charges use 55–90 %, leaving at least 10 % headroom. The 250.0 gr projectile in 0.338" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2218, ADI AR 2225 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. Hodgdon Retumbo, ReloadSwiss RS 76, Vihtavuori N570 rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 250gr | Barnes X S they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Hodgdon US 869, Ramshot LRT burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.