Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 255gr | AERO SOLR,- smax:25.60 bullet and 87 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 Winchester StaBALL HD.
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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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 2700 | <<locked>> | 82% | 61,061 psi | 88% | 2769 fps | 100% |
| Accurate 3100 | <<locked>> | 94% | 62,207 psi | 89% | 2838 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 59,146 psi | 85% | 2808 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 62,497 psi | 90% | 2976 fps | 99.8% |
| ADI APS 450 | <<locked>> | 82% | 61,206 psi | 88% | 2172 fps | 100% |
| ADI AR 2208 | <<locked>> | 82% | 62,816 psi | 90% | 2802 fps | 100% |
| ADI AR 2209 | <<locked>> | 90% | 60,321 psi | 87% | 2884 fps | 100% |
| ADI AR 2213 | <<locked>> | 94% | 62,584 psi | 90% | 2959 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 56,318 psi | 81% | 2871 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 48,776 psi | 70% | 2854 fps | 97.5% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 50,676 psi | 73% | 2838 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 60,379 psi | 87% | 2881 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 60,379 psi | 87% | 2881 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 60,611 psi | 87% | 2864 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 61,815 psi | 89% | 2871 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 59,640 psi | 86% | 2874 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 94% | 62,569 psi | 90% | 2946 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 60,031 psi | 86% | 2841 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 60,017 psi | 86% | 2917 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 61,308 psi | 88% | 2943 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 53,345 psi | 77% | 2907 fps | 98.4% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 59,103 psi | 85% | 2864 fps | 99.1% |
| Bofors RP15 | <<locked>> | 96% | 61,395 psi | 88% | 2933 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 59,524 psi | 86% | 2940 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 62,569 psi | 90% | 2946 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 60,597 psi | 87% | 2808 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 57,986 psi | 83% | 2894 fps | 100% |
| Hodgdon H414 | <<locked>> | 82% | 61,844 psi | 89% | 2881 fps | 100% |
| Hodgdon H4350 | <<locked>> | 86% | 61,569 psi | 88% | 2858 fps | 100% |
| Hodgdon H4831 | <<locked>> | 96% | 61,163 psi | 88% | 2884 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 92% | 60,582 psi | 87% | 2874 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 60,553 psi | 87% | 2779 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 58,958 psi | 85% | 3009 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 62,047 psi | 89% | 2913 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,376 psi | 54% | 1742 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 61,612 psi | 89% | 2776 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 59,872 psi | 86% | 2776 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 62,975 psi | 90% | 2851 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 84% | 62,163 psi | 89% | 2828 fps | 100% |
| IMR 4831 | <<locked>> | 90% | 60,974 psi | 88% | 2818 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 62,149 psi | 89% | 2867 fps | 100% |
| IMR 7828 SSC | <<locked>> | 92% | 60,814 psi | 87% | 2943 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 98% | 60,597 psi | 87% | 2812 fps | 96.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 46,122 psi | 66% | 2756 fps | 99.5% |
| Lovex S065 | <<locked>> | 86% | 62,845 psi | 90% | 2818 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 61,221 psi | 88% | 2825 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 59,625 psi | 86% | 2808 fps | 100% |
| Norma 204 | <<locked>> | 86% | 60,611 psi | 87% | 2867 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 46,731 psi | 67% | 2779 fps | 100% |
| Norma MRP | <<locked>> | 92% | 62,888 psi | 90% | 2963 fps | 100% |
| Norma URP | <<locked>> | 86% | 61,206 psi | 88% | 2841 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 61,177 psi | 88% | 2953 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 60,249 psi | 87% | 2858 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 62,540 psi | 90% | 2917 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,319 psi | 55% | 1785 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 59,538 psi | 86% | 2835 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 62,540 psi | 90% | 2920 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 60,176 psi | 86% | 3005 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 59,205 psi | 85% | 2976 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 82% | 62,424 psi | 90% | 2792 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 60,988 psi | 88% | 2851 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 59,364 psi | 85% | 2864 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 60,597 psi | 87% | 2808 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 86% | 62,845 psi | 90% | 2818 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 61,221 psi | 88% | 2825 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 61,250 psi | 88% | 2648 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 62,207 psi | 89% | 2782 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 58,943 psi | 85% | 2861 fps | 100% |
| Somchem S355 | <<locked>> | 82% | 61,714 psi | 89% | 2782 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 62,787 psi | 90% | 2848 fps | 100% |
| Somchem S365 | <<locked>> | 88% | 62,714 psi | 90% | 2838 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 59,582 psi | 86% | 2828 fps | 100% |
| Unknown powder | <<locked>> | 84% | 61,279 psi | 88% | 2841 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 60,234 psi | 87% | 2720 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 61,627 psi | 89% | 2808 fps | 100% |
| Vihtavuori N165 | <<locked>> | 96% | 61,279 psi | 88% | 2838 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 52,098 psi | 75% | 2753 fps | 96.5% |
| Vihtavuori N550 | <<locked>> | 84% | 62,120 psi | 89% | 2858 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 62,047 psi | 89% | 2867 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 58,856 psi | 85% | 2930 fps | 100% |
| Vihtavuori N565 | <<locked>> | 98% | 62,424 psi | 90% | 2956 fps | 100% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 59,828 psi | 86% | 2976 fps | 99.8% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 57,392 psi | 82% | 2982 fps | 98.7% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 62,758 psi | 90% | 2782 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 61,844 psi | 89% | 2881 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 59,625 psi | 86% | 2936 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 61,453 psi | 88% | 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 2700 | <<locked>> | 80% | 57,246 psi | 82% | 2720 fps | 100% |
| Accurate 3100 | <<locked>> | 80% | 38,682 psi | 56% | 2484 fps | 99.8% |
| Accurate 4350 | <<locked>> | 80% | 51,648 psi | 74% | 2707 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 37,869 psi | 54% | 2552 fps | 95.5% |
| ADI APS 450 | <<locked>> | 80% | 59,161 psi | 85% | 2142 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 59,088 psi | 85% | 2756 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 43,018 psi | 62% | 2615 fps | 99.3% |
| ADI AR 2213 | <<locked>> | 80% | 38,435 psi | 55% | 2556 fps | 97.5% |
| ADI AR 2217 | <<locked>> | 84% | 32,576 psi | 47% | 2418 fps | 95.7% |
| ADI AR 2218 | <<locked>> | 96% | 42,148 psi | 61% | 2717 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 25,730 psi | 37% | 2267 fps | 95.4% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 43,468 psi | 62% | 2615 fps | 99.3% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 43,468 psi | 62% | 2615 fps | 99.3% |
| Alliant Reloder-16 | <<locked>> | 80% | 49,647 psi | 71% | 2713 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 57,595 psi | 83% | 2818 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 43,062 psi | 62% | 2608 fps | 99.3% |
| Alliant Reloder-22 | <<locked>> | 80% | 38,870 psi | 56% | 2562 fps | 98.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 37,608 psi | 54% | 2507 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 32,329 psi | 46% | 2444 fps | 99.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 42,003 psi | 60% | 2661 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 42,467 psi | 61% | 2713 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 40,379 psi | 58% | 2533 fps | 95% |
| Bofors RP15 | <<locked>> | 80% | 36,143 psi | 52% | 2503 fps | 97.9% |
| Bofors RP30 | <<locked>> | 82% | 31,865 psi | 46% | 2431 fps | 95.9% |
| Bofors RP5 | <<locked>> | 80% | 38,870 psi | 56% | 2562 fps | 98.7% |
| Bofors RP7 | <<locked>> | 80% | 53,345 psi | 77% | 2707 fps | 100% |
| Hodgdon H1000 | <<locked>> | 82% | 31,198 psi | 45% | 2385 fps | 95.8% |
| Hodgdon H414 | <<locked>> | 80% | 57,725 psi | 83% | 2828 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 51,097 psi | 73% | 2707 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 36,085 psi | 52% | 2451 fps | 96.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 40,263 psi | 58% | 2543 fps | 97.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 46,673 psi | 67% | 2595 fps | 100% |
| Hodgdon Retumbo | 83.1 gr | 80% | 31,546 psi | 45% | 2477 fps | 97.3% |
| Hodgdon Superformance | <<locked>> | 80% | 53,679 psi | 77% | 2802 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,079 psi | 40% | 1558 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 58,088 psi | 83% | 2730 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 56,289 psi | 81% | 2726 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 48,791 psi | 70% | 2651 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 54,868 psi | 79% | 2730 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 44,411 psi | 64% | 2582 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 42,351 psi | 61% | 2552 fps | 98% |
| IMR 7828 SSC | <<locked>> | 80% | 39,479 psi | 57% | 2589 fps | 97.9% |
| IMR 7977 Enduron | <<locked>> | 96% | 56,695 psi | 81% | 2756 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 88% | 30,516 psi | 44% | 2415 fps | 95% |
| Lovex S065 | <<locked>> | 80% | 52,286 psi | 75% | 2680 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 50,705 psi | 73% | 2680 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 33,199 psi | 48% | 2369 fps | 99.1% |
| Norma 204 | <<locked>> | 80% | 49,385 psi | 71% | 2703 fps | 99.8% |
| Norma 217 | <<locked>> | 84% | 26,600 psi | 38% | 2323 fps | 95.4% |
| Norma MRP | <<locked>> | 80% | 41,046 psi | 59% | 2628 fps | 99.8% |
| Norma URP | <<locked>> | 80% | 50,386 psi | 72% | 2694 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 41,437 psi | 60% | 2644 fps | 98.7% |
| Ramshot Hunter | <<locked>> | 80% | 49,327 psi | 71% | 2703 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,998 psi | 52% | 2500 fps | 98.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,718 psi | 41% | 1594 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 51,750 psi | 74% | 2733 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 50,328 psi | 72% | 2759 fps | 100% |
| ReloadSwiss RS 76 | 89 gr | 80% | 30,589 psi | 44% | 2451 fps | 98.1% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 34,432 psi | 49% | 2530 fps | 95.2% |
| Rottweil R 903 | <<locked>> | 80% | 58,595 psi | 84% | 2746 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 44,121 psi | 63% | 2589 fps | 98.8% |
| Rottweil R 905 | <<locked>> | 80% | 42,366 psi | 61% | 2595 fps | 99.3% |
| Rottweil R 907 | <<locked>> | 80% | 53,345 psi | 77% | 2707 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 52,286 psi | 75% | 2680 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 50,705 psi | 73% | 2680 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 57,725 psi | 83% | 2605 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 51,184 psi | 74% | 2635 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 42,032 psi | 60% | 2592 fps | 99.3% |
| Somchem S355 | <<locked>> | 80% | 58,030 psi | 83% | 2736 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 44,918 psi | 65% | 2582 fps | 98.4% |
| Somchem S365 | <<locked>> | 80% | 47,761 psi | 69% | 2648 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 42,859 psi | 62% | 2572 fps | 99.7% |
| Unknown powder | <<locked>> | 80% | 53,838 psi | 77% | 2746 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 49,995 psi | 72% | 2589 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 53,983 psi | 78% | 2710 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 36,201 psi | 52% | 2434 fps | 98.5% |
| Vihtavuori N170 | <<locked>> | 98% | 48,892 psi | 70% | 2700 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 54,563 psi | 78% | 2756 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 41,901 psi | 60% | 2579 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 39,001 psi | 56% | 2582 fps | 97.2% |
| Vihtavuori N565 | <<locked>> | 80% | 33,489 psi | 48% | 2444 fps | 95.6% |
| Vihtavuori N568 | <<locked>> | 86% | 35,955 psi | 52% | 2549 fps | 95.2% |
| Vihtavuori N570 | <<locked>> | 92% | 42,612 psi | 61% | 2723 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 51,155 psi | 73% | 2641 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 57,725 psi | 83% | 2828 fps | 100% |
| Winchester StaBALL HD | 85.4 gr | 80% | 34,693 psi | 50% | 2556 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 42,917 psi | 62% | 2575 fps | 99.3% |
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 87 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 255gr | AERO SOLR,- smax:25.60. Hodgdon Retumbo delivers the highest muzzle velocity at 3,009 fps; across all powders the maximum-charge window runs from 1,742 fps to 3,009 fps. ADI AR 2217 gives the best case fill at 100 %, and 87 of the 87 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 255.0 gr projectile in 0.338" calls for a 1:10.5 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, Winchester StaBALL HD rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 255gr | AERO SOLR,- smax:25.60 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.