Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 275gr | CutEdge MTH 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 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.
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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 3100 | <<locked>> | 92% | 61,163 psi | 88% | 2723 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 61,917 psi | 89% | 2736 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 61,250 psi | 88% | 2861 fps | 100% |
| ADI APS 450 | <<locked>> | 82% | 61,264 psi | 88% | 2093 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 59,059 psi | 85% | 2769 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 61,380 psi | 88% | 2841 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 59,408 psi | 85% | 2815 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 51,532 psi | 74% | 2822 fps | 98.9% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 53,751 psi | 77% | 2782 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 59,437 psi | 85% | 2743 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 62,265 psi | 89% | 2805 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 61,424 psi | 88% | 2828 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 59,117 psi | 85% | 2726 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 59,263 psi | 85% | 2802 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 60,133 psi | 86% | 2825 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 56,840 psi | 82% | 2864 fps | 99.4% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 47,703 psi | 69% | 2720 fps | 97.6% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 61,612 psi | 89% | 2805 fps | 99.7% |
| Bofors RP15 | <<locked>> | 94% | 60,510 psi | 87% | 2818 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 62,903 psi | 90% | 2877 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 61,424 psi | 88% | 2828 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 62,874 psi | 90% | 2736 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 61,192 psi | 88% | 2831 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 60,220 psi | 87% | 2740 fps | 100% |
| Hodgdon H4831 | <<locked>> | 94% | 59,988 psi | 86% | 2769 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 90% | 59,205 psi | 85% | 2759 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 59,364 psi | 85% | 2661 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 62,569 psi | 90% | 2946 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 60,452 psi | 87% | 2789 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,608 psi | 54% | 1680 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 61,844 psi | 89% | 2700 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 61,525 psi | 88% | 2733 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 60,597 psi | 87% | 2707 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 59,770 psi | 86% | 2700 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 60,640 psi | 87% | 2749 fps | 100% |
| IMR 7828 SSC | <<locked>> | 90% | 59,524 psi | 86% | 2825 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 59,146 psi | 85% | 2703 fps | 97% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,023 psi | 70% | 2710 fps | 99.9% |
| Lovex D100ᴾ | <<locked>> | 100% | 59,103 psi | 85% | 2753 fps | 96.1% |
| Lovex S065 | <<locked>> | 84% | 61,366 psi | 88% | 2700 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 59,901 psi | 86% | 2707 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 62,395 psi | 90% | 2740 fps | 100% |
| Norma 204 | <<locked>> | 84% | 59,088 psi | 85% | 2746 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 49,908 psi | 72% | 2730 fps | 100% |
| Norma MRP | <<locked>> | 90% | 61,685 psi | 89% | 2844 fps | 100% |
| Norma URP | <<locked>> | 84% | 59,959 psi | 86% | 2723 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 59,843 psi | 86% | 2831 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 62,845 psi | 90% | 2785 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 61,090 psi | 88% | 2799 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,450 psi | 55% | 1719 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 62,236 psi | 89% | 2762 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 61,134 psi | 88% | 2799 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 59,292 psi | 85% | 2890 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 58,407 psi | 84% | 2864 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 59,596 psi | 86% | 2736 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 62,076 psi | 89% | 2795 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 62,874 psi | 90% | 2736 fps | 100% |
| Shooters World 50 BMGᴾ | <<locked>> | 100% | 59,103 psi | 85% | 2753 fps | 96.1% |
| Shooters World Long Rifle | <<locked>> | 84% | 61,366 psi | 88% | 2700 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 59,901 psi | 86% | 2707 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 60,510 psi | 87% | 2664 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 61,656 psi | 89% | 2792 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 61,076 psi | 88% | 2730 fps | 100% |
| Somchem S365 | <<locked>> | 86% | 61,496 psi | 88% | 2720 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 62,265 psi | 89% | 2762 fps | 100% |
| Unknown powder | <<locked>> | 82% | 59,973 psi | 86% | 2723 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 62,482 psi | 90% | 2644 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 60,176 psi | 86% | 2687 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 60,249 psi | 87% | 2726 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 54,708 psi | 79% | 2703 fps | 97.8% |
| Vihtavuori N550 | <<locked>> | 82% | 60,713 psi | 87% | 2733 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 61,046 psi | 88% | 2749 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 61,902 psi | 89% | 2867 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 61,482 psi | 88% | 2841 fps | 100% |
| Vihtavuori N568 | <<locked>> | 98% | 58,987 psi | 85% | 2864 fps | 100% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 60,916 psi | 88% | 2933 fps | 99.5% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 61,148 psi | 88% | 2664 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 59,016 psi | 85% | 2822 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 59,930 psi | 86% | 2736 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% | 40,683 psi | 58% | 2434 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 54,027 psi | 78% | 2641 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 40,030 psi | 57% | 2516 fps | 97.1% |
| ADI APS 450 | <<locked>> | 80% | 59,364 psi | 85% | 2067 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 45,194 psi | 65% | 2559 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 40,335 psi | 58% | 2510 fps | 98.7% |
| ADI AR 2217 | <<locked>> | 80% | 29,834 psi | 43% | 2270 fps | 95.5% |
| ADI AR 2218 | <<locked>> | 94% | 41,408 psi | 59% | 2621 fps | 96.2% |
| ADI AR 2225 | <<locked>> | 80% | 27,195 psi | 39% | 2244 fps | 97.5% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,083 psi | 75% | 2648 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,020 psi | 65% | 2552 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 40,930 psi | 59% | 2513 fps | 99.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 39,653 psi | 57% | 2451 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,214 psi | 49% | 2405 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 44,527 psi | 64% | 2608 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 38,870 psi | 56% | 2552 fps | 95.6% |
| Alliant Reloder-50 | <<locked>> | 96% | 40,944 psi | 59% | 2595 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 39,508 psi | 57% | 2434 fps | 95.7% |
| Bofors RP15 | <<locked>> | 80% | 38,029 psi | 55% | 2457 fps | 99% |
| Bofors RP30 | <<locked>> | 80% | 31,575 psi | 45% | 2343 fps | 96.7% |
| Bofors RP5 | <<locked>> | 80% | 40,930 psi | 59% | 2513 fps | 99.5% |
| Bofors RP7 | <<locked>> | 80% | 55,448 psi | 80% | 2641 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 30,647 psi | 44% | 2293 fps | 96.6% |
| Hodgdon H4350 | <<locked>> | 80% | 53,113 psi | 76% | 2641 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 37,884 psi | 54% | 2408 fps | 97.5% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,192 psi | 61% | 2493 fps | 98.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,878 psi | 70% | 2530 fps | 100% |
| Hodgdon Retumbo | 82.1 gr | 80% | 33,417 psi | 48% | 2448 fps | 98.8% |
| Hodgdon Superformance | <<locked>> | 80% | 56,304 psi | 81% | 2736 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,181 psi | 40% | 1499 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 58,305 psi | 84% | 2654 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,894 psi | 73% | 2592 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 56,811 psi | 82% | 2657 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 46,514 psi | 67% | 2520 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,222 psi | 64% | 2500 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 80% | 41,597 psi | 60% | 2546 fps | 99% |
| IMR 7977 Enduron | <<locked>> | 92% | 51,866 psi | 75% | 2598 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 86% | 30,226 psi | 43% | 2329 fps | 95.9% |
| Lovex D100 | <<locked>> | 98% | 54,969 psi | 79% | 2694 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 54,244 psi | 78% | 2608 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 52,707 psi | 76% | 2612 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,012 psi | 50% | 2323 fps | 99.8% |
| Norma 204 | <<locked>> | 80% | 51,590 psi | 74% | 2641 fps | 100% |
| Norma 217 | <<locked>> | 80% | 24,671 psi | 35% | 2185 fps | 95.3% |
| Norma MRP | <<locked>> | 80% | 43,395 psi | 62% | 2579 fps | 100% |
| Norma URP | <<locked>> | 80% | 52,576 psi | 76% | 2625 fps | 100% |
| Ramshot Grand | 87.8 gr | 80% | 43,816 psi | 63% | 2598 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 80% | 51,590 psi | 74% | 2638 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,290 psi | 55% | 2464 fps | 99.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,848 psi | 41% | 1535 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,273 psi | 78% | 2667 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 52,837 psi | 76% | 2694 fps | 100% |
| ReloadSwiss RS 76 | 87.8 gr | 80% | 32,329 psi | 46% | 2421 fps | 99.3% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 34,084 psi | 49% | 2438 fps | 96.1% |
| Rottweil R 904 | <<locked>> | 80% | 46,122 psi | 66% | 2536 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 80% | 44,556 psi | 64% | 2543 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 80% | 55,448 psi | 80% | 2641 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 98% | 54,969 psi | 79% | 2694 fps | 95.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,244 psi | 78% | 2608 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 52,707 psi | 76% | 2612 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,156 psi | 76% | 2569 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,222 psi | 64% | 2539 fps | 99.8% |
| Somchem S361 | <<locked>> | 80% | 46,760 psi | 67% | 2523 fps | 99.2% |
| Somchem S365 | <<locked>> | 80% | 50,285 psi | 72% | 2582 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 44,889 psi | 64% | 2516 fps | 100% |
| Unknown powder | <<locked>> | 80% | 56,086 psi | 81% | 2674 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 51,982 psi | 75% | 2516 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 56,275 psi | 81% | 2641 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 37,971 psi | 55% | 2385 fps | 99.3% |
| Vihtavuori N170 | <<locked>> | 94% | 45,150 psi | 65% | 2549 fps | 95.6% |
| Vihtavuori N550 | <<locked>> | 80% | 56,898 psi | 82% | 2687 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,048 psi | 63% | 2520 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 41,089 psi | 59% | 2539 fps | 98.5% |
| Vihtavuori N565 | <<locked>> | 80% | 35,447 psi | 51% | 2408 fps | 97.2% |
| Vihtavuori N568 | <<locked>> | 84% | 35,534 psi | 51% | 2454 fps | 96% |
| Vihtavuori N570 | <<locked>> | 88% | 39,262 psi | 56% | 2566 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,301 psi | 77% | 2572 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,318 psi | 54% | 2510 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,078 psi | 65% | 2523 fps | 99.8% |
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 | 275gr | CutEdge MTH. Hodgdon Retumbo delivers the highest muzzle velocity at 2,946 fps; across all powders the maximum-charge window runs from 1,680 fps to 2,946 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 275.0 gr projectile in 0.338" calls for a 1:10.0 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, Ramshot Grand rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 275gr | CutEdge MTH 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.