Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 250gr | Lapua Lock Base bullet and 81 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 Ramshot Grand.
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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 92% | 59,117 psi | 85% | 2822 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 59,944 psi | 86% | 2841 fps | 100% |
| Accurate High Country | <<locked>> | 90% | 60,858 psi | 87% | 2989 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 62,033 psi | 89% | 2999 fps | 99.9% |
| ADI APS 450 | <<locked>> | 82% | 61,250 psi | 88% | 2192 fps | 100% |
| ADI AR 2209 | <<locked>> | 90% | 60,655 psi | 87% | 2913 fps | 100% |
| ADI AR 2213 | <<locked>> | 94% | 62,932 psi | 90% | 2986 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 56,739 psi | 82% | 2900 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 49,255 psi | 71% | 2884 fps | 97.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 51,140 psi | 73% | 2867 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 60,771 psi | 87% | 2910 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 60,814 psi | 87% | 2890 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 62,265 psi | 89% | 2900 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 60,046 psi | 86% | 2904 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 94% | 62,975 psi | 90% | 2976 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 60,524 psi | 87% | 2871 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 60,408 psi | 87% | 2946 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 61,830 psi | 89% | 2976 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 53,795 psi | 77% | 2936 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 59,306 psi | 85% | 2890 fps | 99% |
| Bofors RP15 | <<locked>> | 96% | 61,859 psi | 89% | 2959 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 60,060 psi | 86% | 2966 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 62,975 psi | 90% | 2976 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 61,134 psi | 88% | 2838 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 62,627 psi | 90% | 2976 fps | 100% |
| Hodgdon H414 | <<locked>> | 84% | 61,163 psi | 88% | 2897 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 59,567 psi | 86% | 2854 fps | 100% |
| Hodgdon H4831 | <<locked>> | 92% | 62,120 psi | 89% | 2920 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 92% | 60,945 psi | 88% | 2904 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 60,858 psi | 87% | 2808 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 59,321 psi | 85% | 3041 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 62,482 psi | 90% | 2943 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,536 psi | 54% | 1762 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 59,480 psi | 85% | 2831 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 84% | 62,352 psi | 90% | 2854 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 60,031 psi | 86% | 2828 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 62,323 psi | 90% | 2894 fps | 100% |
| IMR 7828 SSC | <<locked>> | 94% | 60,785 psi | 87% | 2966 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 98% | 60,901 psi | 87% | 2838 fps | 96.3% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 46,717 psi | 67% | 2789 fps | 99.5% |
| Lovex S065 | <<locked>> | 84% | 59,727 psi | 86% | 2802 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 61,815 psi | 89% | 2858 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 60,452 psi | 87% | 2838 fps | 100% |
| Norma 204 | <<locked>> | 86% | 60,800 psi | 87% | 2894 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 47,384 psi | 68% | 2815 fps | 100% |
| Norma MRP | <<locked>> | 90% | 59,030 psi | 85% | 2940 fps | 100% |
| Norma URP | <<locked>> | 86% | 61,757 psi | 89% | 2871 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 62,410 psi | 90% | 2992 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 60,524 psi | 87% | 2884 fps | 100% |
| Ramshot Magnum | <<locked>> | 96% | 60,611 psi | 87% | 2920 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,479 psi | 55% | 1804 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 59,959 psi | 86% | 2864 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 62,729 psi | 90% | 2946 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 60,539 psi | 87% | 3035 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 59,712 psi | 86% | 3005 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 90% | 61,380 psi | 88% | 2881 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 59,843 psi | 86% | 2894 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 61,134 psi | 88% | 2838 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 59,727 psi | 86% | 2802 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 61,815 psi | 89% | 2858 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 61,699 psi | 89% | 2674 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 62,569 psi | 90% | 2808 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 59,422 psi | 85% | 2887 fps | 100% |
| Somchem S355 | <<locked>> | 82% | 62,323 psi | 90% | 2815 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 59,176 psi | 85% | 2822 fps | 99.8% |
| Somchem S365 | <<locked>> | 86% | 59,190 psi | 85% | 2822 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 60,162 psi | 86% | 2861 fps | 100% |
| Vihtavuori N150 | <<locked>> | 82% | 59,828 psi | 86% | 2733 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 59,611 psi | 86% | 2808 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 59,872 psi | 86% | 2844 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 62,772 psi | 90% | 2927 fps | 98.1% |
| Vihtavuori N550 | <<locked>> | 86% | 62,613 psi | 90% | 2867 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 62,772 psi | 90% | 2900 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 62,787 psi | 90% | 3005 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 59,016 psi | 85% | 2933 fps | 100% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 60,278 psi | 87% | 3002 fps | 99.8% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 57,087 psi | 82% | 3005 fps | 98.6% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 59,030 psi | 85% | 2762 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 61,380 psi | 88% | 2900 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 60,162 psi | 86% | 2969 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 60,147 psi | 86% | 2861 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% | 39,494 psi | 57% | 2520 fps | 99.9% |
| Accurate 4350 | <<locked>> | 80% | 52,330 psi | 75% | 2740 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 43,033 psi | 62% | 2697 fps | 98.6% |
| Accurate MAGPRO | <<locked>> | 80% | 40,727 psi | 59% | 2641 fps | 97% |
| ADI APS 450 | <<locked>> | 80% | 59,205 psi | 85% | 2165 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 43,555 psi | 63% | 2644 fps | 99.3% |
| ADI AR 2213 | <<locked>> | 80% | 38,899 psi | 56% | 2585 fps | 97.5% |
| ADI AR 2217 | <<locked>> | 84% | 33,112 psi | 48% | 2448 fps | 95.7% |
| ADI AR 2218 | <<locked>> | 96% | 42,714 psi | 61% | 2746 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 80% | 26,498 psi | 38% | 2306 fps | 95.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 43,888 psi | 63% | 2641 fps | 99.3% |
| Alliant Reloder-16 | <<locked>> | 80% | 50,154 psi | 72% | 2743 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 58,102 psi | 83% | 2851 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 43,482 psi | 62% | 2638 fps | 99.3% |
| Alliant Reloder-22 | <<locked>> | 80% | 39,436 psi | 57% | 2592 fps | 98.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 38,189 psi | 55% | 2539 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 33,011 psi | 47% | 2480 fps | 99.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 42,583 psi | 61% | 2694 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 43,120 psi | 62% | 2743 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 43,468 psi | 62% | 2618 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 36,709 psi | 53% | 2533 fps | 97.9% |
| Bofors RP30 | <<locked>> | 82% | 32,648 psi | 47% | 2467 fps | 96% |
| Bofors RP5 | <<locked>> | 80% | 39,436 psi | 57% | 2592 fps | 98.7% |
| Bofors RP7 | <<locked>> | 80% | 53,925 psi | 77% | 2736 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 31,430 psi | 45% | 2405 fps | 95.6% |
| Hodgdon H414 | <<locked>> | 80% | 53,737 psi | 77% | 2795 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 55,883 psi | 80% | 2802 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 41,524 psi | 60% | 2585 fps | 97.5% |
| Hodgdon H4831 SC | <<locked>> | 80% | 40,727 psi | 59% | 2569 fps | 97.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 47,123 psi | 68% | 2625 fps | 100% |
| Hodgdon Retumbo | 83.3 gr | 80% | 32,271 psi | 46% | 2513 fps | 97.4% |
| Hodgdon Superformance | <<locked>> | 80% | 53,998 psi | 78% | 2828 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,137 psi | 40% | 1575 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 49,298 psi | 71% | 2680 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 55,143 psi | 79% | 2756 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 49,501 psi | 71% | 2684 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 42,888 psi | 62% | 2579 fps | 97.9% |
| IMR 7828 SSC | <<locked>> | 80% | 37,637 psi | 54% | 2569 fps | 97.2% |
| IMR 7977 Enduron | <<locked>> | 96% | 57,058 psi | 82% | 2782 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 88% | 31,212 psi | 45% | 2451 fps | 95.1% |
| Lovex S065 | <<locked>> | 80% | 52,779 psi | 76% | 2707 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 51,213 psi | 74% | 2707 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 34,084 psi | 49% | 2405 fps | 99.2% |
| Norma 204 | <<locked>> | 80% | 49,719 psi | 71% | 2730 fps | 99.8% |
| Norma 217 | <<locked>> | 84% | 27,383 psi | 39% | 2362 fps | 95.6% |
| Norma MRP | <<locked>> | 80% | 41,611 psi | 60% | 2661 fps | 99.8% |
| Norma URP | <<locked>> | 80% | 50,865 psi | 73% | 2723 fps | 100% |
| Ramshot Grand | 85.7 gr | 80% | 37,347 psi | 54% | 2575 fps | 97.5% |
| Ramshot Hunter | <<locked>> | 80% | 49,719 psi | 71% | 2733 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 33,402 psi | 48% | 2461 fps | 97.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,921 psi | 42% | 1614 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 52,431 psi | 75% | 2762 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 50,662 psi | 73% | 2789 fps | 100% |
| ReloadSwiss RS 76 | 89.1 gr | 80% | 31,227 psi | 45% | 2484 fps | 98.1% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 35,230 psi | 51% | 2566 fps | 95.3% |
| Rottweil R 904 | <<locked>> | 80% | 44,657 psi | 64% | 2618 fps | 98.7% |
| Rottweil R 905 | <<locked>> | 80% | 43,018 psi | 62% | 2628 fps | 99.3% |
| Rottweil R 907 | <<locked>> | 80% | 53,925 psi | 77% | 2736 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 52,779 psi | 76% | 2707 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 51,213 psi | 74% | 2707 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 58,030 psi | 83% | 2631 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 51,692 psi | 74% | 2661 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 42,670 psi | 61% | 2621 fps | 99.2% |
| Somchem S355 | <<locked>> | 80% | 58,508 psi | 84% | 2766 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 45,353 psi | 65% | 2605 fps | 98.3% |
| Somchem S365 | <<locked>> | 80% | 48,443 psi | 70% | 2680 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 43,468 psi | 62% | 2605 fps | 99.7% |
| Vihtavuori N150 | <<locked>> | 80% | 56,086 psi | 81% | 2687 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 52,301 psi | 75% | 2713 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 37,840 psi | 54% | 2487 fps | 98.7% |
| Vihtavuori N170 | <<locked>> | 92% | 48,037 psi | 69% | 2700 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 51,576 psi | 74% | 2720 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 42,641 psi | 61% | 2612 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 41,510 psi | 60% | 2654 fps | 97.7% |
| Vihtavuori N565 | <<locked>> | 80% | 34,360 psi | 49% | 2484 fps | 95.7% |
| Vihtavuori N568 | <<locked>> | 86% | 36,666 psi | 53% | 2582 fps | 95.2% |
| Vihtavuori N570 | <<locked>> | 92% | 42,960 psi | 62% | 2753 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 51,445 psi | 74% | 2667 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 53,896 psi | 77% | 2795 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 35,273 psi | 51% | 2592 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 39,871 psi | 57% | 2536 fps | 98.7% |
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 81 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 250gr | Lapua Lock Base. Hodgdon Retumbo delivers the highest muzzle velocity at 3,041 fps; across all powders the maximum-charge window runs from 1,762 fps to 3,041 fps. ADI AR 2217 gives the best case fill at 100 %, and 81 of the 81 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 1:13.5 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, Ramshot Grand rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 250gr | Lapua Lock Base 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.