Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 300gr | Sierra HPBT LR MatchKing bullet and 67 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N570, Hodgdon Retumbo and Alliant Reloder-33.
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>> | 88% | 61,163 psi | 88% | 2615 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 47,863 psi | 69% | 2575 fps | 98.5% |
| Accurate MAGPRO | <<locked>> | 86% | 60,263 psi | 87% | 2743 fps | 100% |
| ADI APS 450 | <<locked>> | 82% | 61,685 psi | 89% | 2031 fps | 100% |
| ADI AR 2209 | <<locked>> | 86% | 62,250 psi | 89% | 2697 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 60,945 psi | 88% | 2726 fps | 100% |
| ADI AR 2217 | <<locked>> | 96% | 59,814 psi | 86% | 2710 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 60,263 psi | 87% | 2858 fps | 100% |
| ADI AR 2225 | <<locked>> | 98% | 58,929 psi | 85% | 2730 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 62,613 psi | 90% | 2664 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 61,641 psi | 89% | 2690 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 61,308 psi | 88% | 2717 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 59,524 psi | 86% | 2615 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 60,046 psi | 86% | 2694 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 60,495 psi | 87% | 2707 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 62,221 psi | 89% | 2828 fps | 100% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 57,653 psi | 83% | 2772 fps | 99.7% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 60,713 psi | 87% | 2697 fps | 100% |
| Bofors RP15 | <<locked>> | 90% | 60,611 psi | 87% | 2707 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 59,640 psi | 86% | 2726 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 61,308 psi | 88% | 2717 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 61,525 psi | 88% | 2726 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 59,437 psi | 85% | 2661 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 88% | 62,468 psi | 90% | 2697 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 62,540 psi | 90% | 2585 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 59,596 psi | 86% | 2789 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,956 psi | 55% | 1627 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 60,263 psi | 87% | 2612 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 61,395 psi | 88% | 2608 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 59,611 psi | 86% | 2635 fps | 100% |
| IMR 7828 SSC | <<locked>> | 88% | 59,437 psi | 85% | 2713 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 94% | 61,728 psi | 89% | 2651 fps | 98.5% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 57,827 psi | 83% | 2723 fps | 100% |
| Lovex D100 | <<locked>> | 98% | 62,961 psi | 90% | 2713 fps | 98% |
| Lovex S070 | <<locked>> | 82% | 62,569 psi | 90% | 2631 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 62,859 psi | 90% | 2635 fps | 100% |
| Norma 204 | <<locked>> | 82% | 61,946 psi | 89% | 2677 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 59,364 psi | 85% | 2740 fps | 100% |
| Norma MRP | <<locked>> | 86% | 61,612 psi | 89% | 2730 fps | 100% |
| Norma URP | <<locked>> | 82% | 62,932 psi | 90% | 2644 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 61,076 psi | 88% | 2736 fps | 100% |
| Ramshot Hunter | <<locked>> | 82% | 62,018 psi | 89% | 2664 fps | 100% |
| Ramshot LRTᴾ | <<locked>> | 100% | 59,495 psi | 85% | 2785 fps | 97.4% |
| Ramshot Magnum | <<locked>> | 90% | 59,248 psi | 85% | 2667 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,015 psi | 56% | 1667 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 60,452 psi | 87% | 2779 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 59,480 psi | 85% | 2769 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 62,424 psi | 90% | 2667 fps | 100% |
| Rottweil R 905 | <<locked>> | 86% | 61,656 psi | 89% | 2684 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 98% | 62,961 psi | 90% | 2713 fps | 98% |
| Shooters World SW4350 | <<locked>> | 82% | 62,569 psi | 90% | 2631 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 50,024 psi | 72% | 2585 fps | 98.5% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 62,729 psi | 90% | 2585 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 61,264 psi | 88% | 2680 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 59,814 psi | 86% | 2618 fps | 100% |
| Somchem S365 | <<locked>> | 82% | 61,163 psi | 88% | 2602 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 61,830 psi | 89% | 2648 fps | 100% |
| Vihtavuori 24N41ᴾ | <<locked>> | 100% | 57,696 psi | 83% | 2700 fps | 96.8% |
| Vihtavuori N165 | <<locked>> | 90% | 61,743 psi | 89% | 2638 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 60,771 psi | 87% | 2694 fps | 99.4% |
| Vihtavuori N555 | <<locked>> | 86% | 61,337 psi | 88% | 2638 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 60,887 psi | 87% | 2743 fps | 100% |
| Vihtavuori N565 | <<locked>> | 92% | 62,047 psi | 89% | 2740 fps | 100% |
| Vihtavuori N568 | <<locked>> | 94% | 59,843 psi | 86% | 2766 fps | 100% |
| Vihtavuori N570 | <<locked>> | 96% | 61,424 psi | 88% | 2835 fps | 99.9% |
| Winchester StaBALL HD | <<locked>> | 88% | 60,524 psi | 87% | 2710 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 61,685 psi | 89% | 2651 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% | 47,021 psi | 68% | 2431 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 35,984 psi | 52% | 2352 fps | 95.1% |
| Accurate MAGPRO | <<locked>> | 80% | 49,052 psi | 70% | 2582 fps | 99.8% |
| ADI APS 450 | <<locked>> | 80% | 59,480 psi | 85% | 2005 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 51,198 psi | 74% | 2552 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 46,325 psi | 67% | 2520 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 34,679 psi | 50% | 2306 fps | 98.7% |
| ADI AR 2218 | <<locked>> | 86% | 36,419 psi | 52% | 2428 fps | 95.9% |
| ADI AR 2225 | <<locked>> | 80% | 32,010 psi | 46% | 2290 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 58,697 psi | 84% | 2618 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 50,908 psi | 73% | 2546 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,079 psi | 68% | 2520 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,021 psi | 66% | 2441 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,176 psi | 58% | 2415 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 52,446 psi | 75% | 2608 fps | 100% |
| Alliant Reloder-33 | 94.1 gr | 82% | 34,679 psi | 50% | 2362 fps | 95.3% |
| Alliant Reloder-50 | <<locked>> | 88% | 37,275 psi | 54% | 2421 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,077 psi | 63% | 2441 fps | 98.2% |
| Bofors RP15 | <<locked>> | 80% | 43,961 psi | 63% | 2467 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 37,478 psi | 54% | 2375 fps | 99.3% |
| Bofors RP5 | <<locked>> | 80% | 47,079 psi | 68% | 2520 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 37,637 psi | 54% | 2369 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 80% | 48,776 psi | 70% | 2510 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 47,877 psi | 69% | 2497 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 55,158 psi | 79% | 2503 fps | 100% |
| Hodgdon Retumbo | 85.1 gr | 80% | 39,276 psi | 56% | 2480 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,572 psi | 41% | 1453 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 56,681 psi | 81% | 2566 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 57,638 psi | 83% | 2566 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,472 psi | 71% | 2493 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 45,237 psi | 65% | 2507 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 45,078 psi | 65% | 2402 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 80% | 29,602 psi | 43% | 2218 fps | 97% |
| Lovex D100 | <<locked>> | 92% | 50,995 psi | 73% | 2549 fps | 95.8% |
| Lovex S070 | <<locked>> | 80% | 58,813 psi | 84% | 2585 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 40,698 psi | 58% | 2329 fps | 100% |
| Norma 204 | <<locked>> | 80% | 57,943 psi | 83% | 2628 fps | 100% |
| Norma 217 | <<locked>> | 80% | 29,892 psi | 43% | 2241 fps | 99% |
| Norma MRP | <<locked>> | 80% | 50,227 psi | 72% | 2579 fps | 100% |
| Norma URP | <<locked>> | 80% | 59,103 psi | 85% | 2598 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 45,774 psi | 66% | 2523 fps | 100% |
| Ramshot Hunter | <<locked>> | 80% | 58,102 psi | 83% | 2618 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 51,735 psi | 74% | 2667 fps | 95.8% |
| Ramshot Magnum | <<locked>> | 80% | 41,089 psi | 59% | 2411 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,443 psi | 42% | 1490 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 38,551 psi | 55% | 2457 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 35,418 psi | 51% | 2369 fps | 97.8% |
| Rottweil R 904 | <<locked>> | 80% | 51,619 psi | 74% | 2523 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 50,749 psi | 73% | 2539 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 50,995 psi | 73% | 2549 fps | 95.8% |
| Shooters World SW4350 | <<locked>> | 80% | 58,813 psi | 84% | 2585 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 38,116 psi | 55% | 2375 fps | 95.6% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 58,943 psi | 85% | 2543 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 50,415 psi | 72% | 2536 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 52,518 psi | 75% | 2520 fps | 100% |
| Somchem S365 | <<locked>> | 80% | 57,319 psi | 82% | 2556 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 50,937 psi | 73% | 2507 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 96% | 50,183 psi | 72% | 2589 fps | 95% |
| Vihtavuori N165 | <<locked>> | 80% | 44,730 psi | 64% | 2408 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 40,886 psi | 59% | 2379 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 80% | 50,836 psi | 73% | 2507 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 49,719 psi | 71% | 2585 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 41,597 psi | 60% | 2434 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 80% | 36,695 psi | 53% | 2385 fps | 97.6% |
| Vihtavuori N570 | 90.5 gr | 82% | 37,405 psi | 54% | 2431 fps | 96% |
| Winchester StaBALL HD | <<locked>> | 80% | 45,266 psi | 65% | 2516 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 47,050 psi | 68% | 2457 fps | 100% |
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 70 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 300gr | Sierra HPBT LR MatchKing. ADI AR 2218 delivers the highest muzzle velocity at 2,858 fps; across all powders the maximum-charge window runs from 1,627 fps to 2,858 fps. Accurate 8700 gives the best case fill at 100 %, and 70 of the 70 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (480 MPa), the top charges use 55–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.338" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2218, Alliant Reloder-50 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. Vihtavuori N570, Hodgdon Retumbo, Alliant Reloder-33 rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 300gr | Sierra HPBT LR MatchKing 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.