Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 250gr | Sako Hammerhead bullet and 79 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 Accurate MAGPRO.
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>> | 92% | 61,743 psi | 89% | 2864 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 62,540 psi | 90% | 2881 fps | 100% |
| Accurate High Country | <<locked>> | 88% | 59,698 psi | 86% | 2979 fps | 100% |
| Accurate MAGPRO | <<locked>> | 90% | 60,800 psi | 87% | 2989 fps | 99.9% |
| ADI APS 450 | <<locked>> | 82% | 61,264 psi | 88% | 2215 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 59,306 psi | 85% | 2904 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 61,612 psi | 89% | 2979 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 59,785 psi | 86% | 2949 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 52,040 psi | 75% | 2946 fps | 98.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,273 psi | 78% | 2917 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 59,408 psi | 85% | 2900 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 59,524 psi | 86% | 2881 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 62,671 psi | 90% | 2946 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 61,801 psi | 89% | 2969 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 59,625 psi | 86% | 2864 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 59,727 psi | 86% | 2943 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 60,669 psi | 87% | 2966 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 57,392 psi | 82% | 2999 fps | 99% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 48,747 psi | 70% | 2854 fps | 97.1% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 61,844 psi | 89% | 2936 fps | 99.4% |
| Bofors RP15 | <<locked>> | 94% | 60,872 psi | 87% | 2956 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 59,364 psi | 85% | 2966 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 61,801 psi | 89% | 2969 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 59,480 psi | 85% | 2828 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 61,757 psi | 89% | 2972 fps | 100% |
| Hodgdon H414 | <<locked>> | 82% | 59,698 psi | 86% | 2887 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 61,917 psi | 89% | 2897 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 60,785 psi | 87% | 2913 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 90% | 59,509 psi | 85% | 2894 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 59,625 psi | 86% | 2799 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 62,961 psi | 90% | 3091 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 60,974 psi | 88% | 2930 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,608 psi | 54% | 1778 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 61,627 psi | 89% | 2867 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 60,800 psi | 87% | 2844 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 62,410 psi | 90% | 2864 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 60,872 psi | 87% | 2884 fps | 100% |
| IMR 7828 SSC | <<locked>> | 92% | 59,843 psi | 86% | 2963 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 59,379 psi | 85% | 2831 fps | 96.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,632 psi | 71% | 2841 fps | 99.8% |
| Lovex S065 | <<locked>> | 84% | 61,844 psi | 89% | 2841 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 60,263 psi | 87% | 2844 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 59,350 psi | 85% | 2835 fps | 100% |
| Norma 204 | <<locked>> | 84% | 59,277 psi | 85% | 2881 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 50,488 psi | 73% | 2864 fps | 100% |
| Norma MRP | <<locked>> | 90% | 62,178 psi | 89% | 2986 fps | 100% |
| Norma URP | <<locked>> | 84% | 60,278 psi | 87% | 2861 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 61,308 psi | 88% | 2986 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 59,146 psi | 85% | 2874 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 59,524 psi | 86% | 2910 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,551 psi | 55% | 1821 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 62,685 psi | 90% | 2907 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 61,395 psi | 88% | 2936 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 59,712 psi | 86% | 3028 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 59,045 psi | 85% | 3002 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 88% | 59,944 psi | 86% | 2874 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 62,424 psi | 90% | 2936 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 59,480 psi | 85% | 2828 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 61,844 psi | 89% | 2841 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 60,263 psi | 87% | 2844 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 60,945 psi | 88% | 2802 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 61,989 psi | 89% | 2933 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 61,496 psi | 88% | 2864 fps | 100% |
| Somchem S365 | <<locked>> | 86% | 61,757 psi | 89% | 2858 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 62,714 psi | 90% | 2900 fps | 100% |
| Vihtavuori N150 | <<locked>> | 82% | 62,033 psi | 89% | 2769 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 61,975 psi | 89% | 2848 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 62,627 psi | 90% | 2887 fps | 100% |
| Vihtavuori N170 | <<locked>> | 98% | 61,598 psi | 88% | 2923 fps | 98.2% |
| Vihtavuori N550 | <<locked>> | 84% | 61,148 psi | 88% | 2858 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 61,757 psi | 89% | 2894 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 61,569 psi | 88% | 2995 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 62,149 psi | 89% | 2982 fps | 100% |
| Vihtavuori N568 | <<locked>> | 98% | 59,538 psi | 86% | 2999 fps | 99.8% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 60,771 psi | 87% | 3068 fps | 99.2% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 61,525 psi | 88% | 2799 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 59,872 psi | 86% | 2887 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 59,625 psi | 86% | 2963 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 62,932 psi | 90% | 2904 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% | 41,524 psi | 60% | 2562 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 54,766 psi | 79% | 2782 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 45,310 psi | 65% | 2746 fps | 99.1% |
| Accurate MAGPRO | 91.9 gr | 80% | 42,815 psi | 62% | 2690 fps | 97.7% |
| ADI APS 450 | <<locked>> | 80% | 59,306 psi | 85% | 2185 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 45,498 psi | 65% | 2687 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 80% | 40,770 psi | 59% | 2631 fps | 98.2% |
| ADI AR 2217 | <<locked>> | 82% | 32,561 psi | 47% | 2441 fps | 95.8% |
| ADI AR 2218 | <<locked>> | 94% | 41,945 psi | 60% | 2740 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 80% | 27,789 psi | 40% | 2356 fps | 96.8% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 45,890 psi | 66% | 2687 fps | 99.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,286 psi | 75% | 2782 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,484 psi | 65% | 2684 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,437 psi | 60% | 2641 fps | 99.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,263 psi | 58% | 2579 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,737 psi | 50% | 2526 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,121 psi | 65% | 2740 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 42,641 psi | 61% | 2740 fps | 95.9% |
| Alliant Reloder-50 | <<locked>> | 96% | 41,959 psi | 60% | 2723 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 42,366 psi | 61% | 2605 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 38,566 psi | 55% | 2579 fps | 98.5% |
| Bofors RP30 | <<locked>> | 80% | 32,271 psi | 46% | 2461 fps | 96% |
| Bofors RP5 | <<locked>> | 80% | 41,437 psi | 60% | 2641 fps | 99.2% |
| Bofors RP7 | <<locked>> | 80% | 55,912 psi | 80% | 2779 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 32,996 psi | 47% | 2454 fps | 96.7% |
| Hodgdon H414 | <<locked>> | 80% | 55,927 psi | 80% | 2835 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 58,059 psi | 83% | 2844 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 43,410 psi | 62% | 2631 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,583 psi | 61% | 2615 fps | 98% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,139 psi | 71% | 2661 fps | 100% |
| Hodgdon Retumbo | 86.9 gr | 80% | 33,866 psi | 49% | 2562 fps | 98.3% |
| Hodgdon Superformance | <<locked>> | 80% | 56,666 psi | 81% | 2874 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,210 psi | 41% | 1591 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,169 psi | 74% | 2720 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 57,058 psi | 82% | 2795 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 51,590 psi | 74% | 2723 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,541 psi | 64% | 2621 fps | 98.5% |
| IMR 7828 SSC | <<locked>> | 80% | 39,436 psi | 57% | 2615 fps | 97.9% |
| IMR 7977 Enduron | <<locked>> | 94% | 55,753 psi | 80% | 2776 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 86% | 30,951 psi | 44% | 2444 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 54,752 psi | 79% | 2743 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,185 psi | 76% | 2746 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,839 psi | 51% | 2448 fps | 99.5% |
| Norma 204 | <<locked>> | 80% | 51,924 psi | 75% | 2776 fps | 100% |
| Norma 217 | <<locked>> | 82% | 27,180 psi | 39% | 2356 fps | 95.7% |
| Norma MRP | <<locked>> | 80% | 43,816 psi | 63% | 2707 fps | 100% |
| Norma URP | <<locked>> | 80% | 52,997 psi | 76% | 2762 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,421 psi | 57% | 2628 fps | 98.3% |
| Ramshot Hunter | <<locked>> | 80% | 51,967 psi | 75% | 2772 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,375 psi | 51% | 2510 fps | 98.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,993 psi | 42% | 1631 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,810 psi | 79% | 2805 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,258 psi | 77% | 2831 fps | 100% |
| ReloadSwiss RS 76 | 93 gr | 80% | 32,953 psi | 47% | 2536 fps | 98.9% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 34,780 psi | 50% | 2556 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 46,354 psi | 67% | 2657 fps | 99.1% |
| Rottweil R 905 | <<locked>> | 80% | 44,976 psi | 65% | 2671 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 80% | 55,912 psi | 80% | 2779 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,752 psi | 79% | 2743 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,185 psi | 76% | 2746 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,505 psi | 77% | 2700 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,643 psi | 64% | 2664 fps | 99.6% |
| Somchem S361 | <<locked>> | 80% | 47,253 psi | 68% | 2651 fps | 98.8% |
| Somchem S365 | <<locked>> | 80% | 50,720 psi | 73% | 2717 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,426 psi | 65% | 2644 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 80% | 58,146 psi | 84% | 2723 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 54,534 psi | 78% | 2753 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,697 psi | 57% | 2530 fps | 99.2% |
| Vihtavuori N170 | <<locked>> | 90% | 47,137 psi | 68% | 2694 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 53,664 psi | 77% | 2756 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,788 psi | 64% | 2651 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,598 psi | 63% | 2700 fps | 98.4% |
| Vihtavuori N565 | <<locked>> | 80% | 36,187 psi | 52% | 2530 fps | 96.6% |
| Vihtavuori N568 | <<locked>> | 84% | 36,143 psi | 52% | 2572 fps | 95.2% |
| Vihtavuori N570 | <<locked>> | 90% | 42,438 psi | 61% | 2749 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,664 psi | 77% | 2700 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 56,115 psi | 81% | 2838 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,884 psi | 54% | 2638 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,727 psi | 60% | 2579 fps | 99.2% |
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 79 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 250gr | Sako Hammerhead. Hodgdon Retumbo delivers the highest muzzle velocity at 3,091 fps; across all powders the maximum-charge window runs from 1,778 fps to 3,091 fps. ADI AR 2217 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 54–90 %, leaving at least 10 % headroom. The 250.0 gr projectile in 0.338" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, 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, Accurate MAGPRO rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 250gr | Sako Hammerhead 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.