Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 277gr | CutEdge MTAC 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 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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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% | 61,453 psi | 88% | 2720 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 62,149 psi | 89% | 2730 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 61,583 psi | 88% | 2854 fps | 100% |
| ADI APS 450 | <<locked>> | 82% | 61,337 psi | 88% | 2087 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 59,277 psi | 85% | 2759 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 61,641 psi | 89% | 2835 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 59,698 psi | 86% | 2808 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 51,808 psi | 74% | 2818 fps | 99% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,041 psi | 78% | 2776 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 59,640 psi | 86% | 2733 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 62,511 psi | 90% | 2799 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 61,714 psi | 89% | 2825 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 59,364 psi | 85% | 2720 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 59,582 psi | 86% | 2795 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 60,466 psi | 87% | 2818 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 57,188 psi | 82% | 2861 fps | 99.4% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 48,022 psi | 69% | 2720 fps | 97.7% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 61,888 psi | 89% | 2799 fps | 99.7% |
| Bofors RP15 | <<locked>> | 94% | 60,814 psi | 87% | 2812 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 59,176 psi | 85% | 2822 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 61,714 psi | 89% | 2825 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 59,234 psi | 85% | 2680 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 61,496 psi | 88% | 2825 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 60,597 psi | 87% | 2733 fps | 100% |
| Hodgdon H4831 | <<locked>> | 94% | 60,234 psi | 87% | 2762 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 90% | 59,466 psi | 85% | 2756 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 59,567 psi | 86% | 2654 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 62,932 psi | 90% | 2940 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 60,901 psi | 87% | 2785 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,521 psi | 54% | 1670 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 61,989 psi | 89% | 2694 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 61,699 psi | 89% | 2726 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 60,771 psi | 87% | 2700 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 60,017 psi | 86% | 2694 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 60,829 psi | 87% | 2743 fps | 100% |
| IMR 7828 SSC | <<locked>> | 90% | 59,814 psi | 86% | 2818 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 59,350 psi | 85% | 2697 fps | 97.1% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,327 psi | 71% | 2707 fps | 100% |
| Lovex D100ᴾ | <<locked>> | 100% | 59,437 psi | 85% | 2746 fps | 96.2% |
| Lovex S065 | <<locked>> | 84% | 61,757 psi | 89% | 2694 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 60,075 psi | 86% | 2700 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 62,859 psi | 90% | 2733 fps | 100% |
| Norma 204 | <<locked>> | 84% | 59,277 psi | 85% | 2740 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 50,212 psi | 72% | 2726 fps | 100% |
| Norma MRP | <<locked>> | 90% | 61,960 psi | 89% | 2838 fps | 100% |
| Norma URP | <<locked>> | 84% | 60,191 psi | 86% | 2713 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 60,191 psi | 86% | 2825 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 59,117 psi | 85% | 2730 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 61,395 psi | 88% | 2792 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,508 psi | 55% | 1713 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 62,511 psi | 90% | 2759 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 61,380 psi | 88% | 2789 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 59,654 psi | 86% | 2884 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 58,755 psi | 84% | 2861 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 59,785 psi | 86% | 2730 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 62,308 psi | 90% | 2789 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 59,234 psi | 85% | 2680 fps | 100% |
| Shooters World 50 BMGᴾ | <<locked>> | 100% | 59,437 psi | 85% | 2746 fps | 96.2% |
| Shooters World Long Rifle | <<locked>> | 84% | 61,757 psi | 89% | 2694 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 60,075 psi | 86% | 2700 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 60,713 psi | 87% | 2654 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 61,888 psi | 89% | 2785 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 61,482 psi | 88% | 2726 fps | 100% |
| Somchem S365 | <<locked>> | 86% | 61,728 psi | 89% | 2713 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 62,497 psi | 90% | 2756 fps | 100% |
| Unknown powder | <<locked>> | 82% | 60,176 psi | 86% | 2717 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 62,685 psi | 90% | 2635 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 60,365 psi | 87% | 2680 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 60,481 psi | 87% | 2720 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 54,940 psi | 79% | 2700 fps | 97.9% |
| Vihtavuori N550 | <<locked>> | 82% | 60,945 psi | 88% | 2726 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 61,308 psi | 88% | 2743 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 62,207 psi | 89% | 2864 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 61,772 psi | 89% | 2838 fps | 100% |
| Vihtavuori N568 | <<locked>> | 98% | 59,306 psi | 85% | 2858 fps | 100% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 61,264 psi | 88% | 2927 fps | 99.6% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 61,366 psi | 88% | 2654 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 59,422 psi | 85% | 2815 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 60,162 psi | 86% | 2730 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% | 40,843 psi | 59% | 2428 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 54,244 psi | 78% | 2631 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 40,234 psi | 58% | 2510 fps | 97.3% |
| ADI APS 450 | <<locked>> | 80% | 59,248 psi | 85% | 2057 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 45,353 psi | 65% | 2556 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 40,524 psi | 58% | 2507 fps | 98.8% |
| ADI AR 2217 | <<locked>> | 80% | 30,066 psi | 43% | 2267 fps | 95.7% |
| ADI AR 2218 | <<locked>> | 92% | 38,682 psi | 56% | 2552 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 80% | 27,325 psi | 39% | 2241 fps | 97.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,272 psi | 75% | 2638 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,179 psi | 65% | 2549 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,104 psi | 59% | 2510 fps | 99.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 39,958 psi | 57% | 2448 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,389 psi | 49% | 2398 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 44,918 psi | 65% | 2605 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 39,131 psi | 56% | 2549 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 96% | 41,220 psi | 59% | 2595 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 39,639 psi | 57% | 2431 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 38,334 psi | 55% | 2454 fps | 99.1% |
| Bofors RP30 | <<locked>> | 80% | 31,734 psi | 46% | 2336 fps | 96.8% |
| Bofors RP5 | <<locked>> | 80% | 41,104 psi | 59% | 2510 fps | 99.6% |
| Bofors RP7 | <<locked>> | 80% | 55,637 psi | 80% | 2635 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 30,879 psi | 44% | 2293 fps | 96.8% |
| Hodgdon H4350 | <<locked>> | 80% | 53,447 psi | 77% | 2638 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 38,043 psi | 55% | 2402 fps | 97.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,366 psi | 61% | 2487 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,081 psi | 71% | 2523 fps | 100% |
| Hodgdon Retumbo | 82 gr | 80% | 33,591 psi | 48% | 2444 fps | 99% |
| Hodgdon Superformance | <<locked>> | 80% | 56,536 psi | 81% | 2730 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,224 psi | 41% | 1493 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 58,436 psi | 84% | 2648 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,039 psi | 73% | 2582 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 57,145 psi | 82% | 2654 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 46,702 psi | 67% | 2513 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,382 psi | 64% | 2493 fps | 99% |
| IMR 7828 SSC | <<locked>> | 80% | 41,945 psi | 60% | 2543 fps | 99.1% |
| IMR 7977 Enduron | <<locked>> | 92% | 52,214 psi | 75% | 2595 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 84% | 28,471 psi | 41% | 2274 fps | 95.1% |
| Lovex D100 | <<locked>> | 98% | 55,230 psi | 79% | 2687 fps | 95.3% |
| Lovex S065 | <<locked>> | 80% | 54,549 psi | 78% | 2602 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,026 psi | 76% | 2608 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,157 psi | 51% | 2320 fps | 99.8% |
| Norma 204 | <<locked>> | 80% | 51,793 psi | 74% | 2638 fps | 100% |
| Norma 217 | <<locked>> | 80% | 24,801 psi | 36% | 2182 fps | 95.5% |
| Norma MRP | <<locked>> | 80% | 43,584 psi | 63% | 2572 fps | 100% |
| Norma URP | <<locked>> | 80% | 52,924 psi | 76% | 2621 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 44,193 psi | 63% | 2595 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 80% | 51,764 psi | 74% | 2631 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,493 psi | 55% | 2457 fps | 99.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,892 psi | 42% | 1529 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,491 psi | 78% | 2657 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,229 psi | 76% | 2690 fps | 100% |
| ReloadSwiss RS 76 | 87.8 gr | 80% | 32,605 psi | 47% | 2418 fps | 99.4% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 31,778 psi | 46% | 2375 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 46,282 psi | 66% | 2530 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 80% | 44,715 psi | 64% | 2536 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 80% | 55,637 psi | 80% | 2635 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 98% | 55,230 psi | 79% | 2687 fps | 95.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,549 psi | 78% | 2602 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,026 psi | 76% | 2608 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,287 psi | 77% | 2562 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,382 psi | 64% | 2533 fps | 99.8% |
| Somchem S361 | <<locked>> | 80% | 47,079 psi | 68% | 2520 fps | 99.3% |
| Somchem S365 | <<locked>> | 80% | 50,488 psi | 73% | 2575 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,034 psi | 65% | 2510 fps | 100% |
| Unknown powder | <<locked>> | 80% | 56,260 psi | 81% | 2664 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 52,127 psi | 75% | 2510 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 56,492 psi | 81% | 2635 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,232 psi | 55% | 2382 fps | 99.4% |
| Vihtavuori N170 | <<locked>> | 94% | 45,339 psi | 65% | 2543 fps | 95.8% |
| Vihtavuori N550 | <<locked>> | 80% | 57,072 psi | 82% | 2680 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,382 psi | 64% | 2513 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 41,278 psi | 59% | 2533 fps | 98.6% |
| Vihtavuori N565 | <<locked>> | 80% | 35,752 psi | 51% | 2405 fps | 97.4% |
| Vihtavuori N568 | <<locked>> | 82% | 33,257 psi | 48% | 2395 fps | 95.1% |
| Vihtavuori N570 | 94.6 gr | 88% | 39,479 psi | 57% | 2562 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,693 psi | 77% | 2566 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,594 psi | 54% | 2507 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,237 psi | 65% | 2520 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 86 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 277gr | CutEdge MTAC. Hodgdon Retumbo delivers the highest muzzle velocity at 2,940 fps; across all powders the maximum-charge window runs from 1,670 fps to 2,940 fps. Accurate 8700 gives the best case fill at 100 %, and 86 of the 86 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 277.0 gr projectile in 0.338" calls for a 1:10.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2217, ADI AR 2218 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 | 277gr | CutEdge MTAC 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.