Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 300gr | MAKER Expanding Subsonic bullet and 71 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 ReloadSwiss RS 76.
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% | 59,857 psi | 86% | 2595 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 46,412 psi | 67% | 2546 fps | 98.1% |
| Accurate MAGPRO | <<locked>> | 88% | 62,990 psi | 90% | 2769 fps | 100% |
| ADI APS 450 | <<locked>> | 82% | 61,612 psi | 89% | 2018 fps | 100% |
| ADI AR 2209 | <<locked>> | 86% | 60,930 psi | 88% | 2677 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 59,437 psi | 85% | 2700 fps | 100% |
| ADI AR 2217 | <<locked>> | 98% | 62,424 psi | 90% | 2733 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 58,436 psi | 84% | 2828 fps | 100% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 61,250 psi | 88% | 2753 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 61,264 psi | 88% | 2641 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 60,379 psi | 87% | 2667 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 59,828 psi | 86% | 2690 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 61,859 psi | 89% | 2638 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 62,381 psi | 90% | 2717 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 58,900 psi | 85% | 2684 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 60,495 psi | 87% | 2802 fps | 100% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 55,767 psi | 80% | 2740 fps | 99.5% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 59,495 psi | 85% | 2671 fps | 99.9% |
| Bofors RP15 | <<locked>> | 90% | 59,161 psi | 85% | 2684 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 62,091 psi | 89% | 2749 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 59,828 psi | 86% | 2690 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 59,930 psi | 86% | 2700 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 62,236 psi | 89% | 2687 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 88% | 61,061 psi | 88% | 2671 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 61,308 psi | 88% | 2566 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 62,149 psi | 89% | 2815 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,014 psi | 55% | 1621 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 62,772 psi | 90% | 2635 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 60,147 psi | 86% | 2589 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 62,221 psi | 89% | 2661 fps | 100% |
| IMR 7828 SSC | <<locked>> | 90% | 62,004 psi | 89% | 2740 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 94% | 60,640 psi | 87% | 2628 fps | 98.2% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 56,130 psi | 81% | 2697 fps | 100% |
| Lovex D100 | <<locked>> | 98% | 61,467 psi | 88% | 2684 fps | 97.6% |
| Lovex S065 | <<locked>> | 82% | 62,888 psi | 90% | 2602 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 61,395 psi | 88% | 2612 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 61,583 psi | 88% | 2615 fps | 100% |
| Norma 204 | <<locked>> | 82% | 60,655 psi | 87% | 2654 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 57,551 psi | 83% | 2713 fps | 100% |
| Norma MRP | <<locked>> | 86% | 60,292 psi | 87% | 2707 fps | 100% |
| Norma URP | <<locked>> | 82% | 61,714 psi | 89% | 2621 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 59,480 psi | 85% | 2710 fps | 100% |
| Ramshot Hunter | <<locked>> | 82% | 60,698 psi | 87% | 2644 fps | 100% |
| Ramshot LRTᴾ | <<locked>> | 100% | 57,928 psi | 83% | 2756 fps | 97% |
| Ramshot Magnum | <<locked>> | 92% | 62,018 psi | 89% | 2694 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,928 psi | 56% | 1657 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 58,581 psi | 84% | 2753 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 62,105 psi | 89% | 2795 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 61,163 psi | 88% | 2644 fps | 100% |
| Rottweil R 905 | <<locked>> | 86% | 60,307 psi | 87% | 2657 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 98% | 61,467 psi | 88% | 2684 fps | 97.6% |
| Shooters World Long Rifle | <<locked>> | 82% | 62,888 psi | 90% | 2602 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 61,395 psi | 88% | 2612 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 48,530 psi | 70% | 2556 fps | 98.2% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 61,685 psi | 89% | 2566 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 59,915 psi | 86% | 2654 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 62,685 psi | 90% | 2644 fps | 100% |
| Somchem S365 | <<locked>> | 82% | 59,872 psi | 86% | 2582 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 60,582 psi | 87% | 2628 fps | 100% |
| Vihtavuori 24N41ᴾ | <<locked>> | 100% | 56,159 psi | 81% | 2671 fps | 96.2% |
| Vihtavuori N165 | <<locked>> | 90% | 60,379 psi | 87% | 2615 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 59,480 psi | 85% | 2667 fps | 99.2% |
| Vihtavuori N550 | <<locked>> | 82% | 62,395 psi | 90% | 2621 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 59,944 psi | 86% | 2615 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 59,596 psi | 86% | 2720 fps | 100% |
| Vihtavuori N565 | <<locked>> | 92% | 60,495 psi | 87% | 2717 fps | 100% |
| Vihtavuori N568 | <<locked>> | 96% | 62,366 psi | 90% | 2792 fps | 100% |
| Vihtavuori N570 | <<locked>> | 96% | 59,698 psi | 86% | 2805 fps | 99.8% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 62,656 psi | 90% | 2566 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 88% | 58,769 psi | 84% | 2687 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 60,321 psi | 87% | 2628 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% | 46,050 psi | 66% | 2411 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 37,521 psi | 54% | 2379 fps | 95.6% |
| Accurate MAGPRO | <<locked>> | 80% | 47,848 psi | 69% | 2556 fps | 99.7% |
| ADI APS 450 | <<locked>> | 80% | 59,567 psi | 86% | 1991 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 50,038 psi | 72% | 2530 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 45,324 psi | 65% | 2497 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 33,895 psi | 49% | 2280 fps | 98.4% |
| ADI AR 2218 | <<locked>> | 86% | 35,447 psi | 51% | 2395 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 31,125 psi | 45% | 2264 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 80% | 57,493 psi | 83% | 2598 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 49,922 psi | 72% | 2523 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 46,079 psi | 66% | 2497 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 44,947 psi | 65% | 2421 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 39,030 psi | 56% | 2392 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 51,053 psi | 73% | 2585 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 36,216 psi | 52% | 2395 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 88% | 36,027 psi | 52% | 2392 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 43,250 psi | 62% | 2421 fps | 97.9% |
| Bofors RP15 | <<locked>> | 80% | 42,960 psi | 62% | 2444 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 36,535 psi | 52% | 2352 fps | 99% |
| Bofors RP5 | <<locked>> | 80% | 46,079 psi | 66% | 2497 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 36,811 psi | 53% | 2346 fps | 99.4% |
| Hodgdon H4831 | <<locked>> | 80% | 47,747 psi | 69% | 2487 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 46,963 psi | 67% | 2474 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 54,041 psi | 78% | 2484 fps | 100% |
| Hodgdon Retumbo | 83.2 gr | 80% | 38,159 psi | 55% | 2451 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,543 psi | 41% | 1447 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 55,535 psi | 80% | 2546 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 56,420 psi | 81% | 2543 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 48,472 psi | 70% | 2467 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 44,077 psi | 63% | 2480 fps | 99.8% |
| IMR 7977 Enduron | <<locked>> | 86% | 47,050 psi | 68% | 2428 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 80% | 28,776 psi | 41% | 2195 fps | 96.5% |
| Lovex D100 | <<locked>> | 92% | 49,719 psi | 71% | 2520 fps | 95.3% |
| Lovex S065 | <<locked>> | 80% | 59,219 psi | 85% | 2559 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 57,827 psi | 83% | 2569 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 39,813 psi | 57% | 2310 fps | 100% |
| Norma 204 | <<locked>> | 80% | 56,811 psi | 82% | 2605 fps | 100% |
| Norma 217 | <<locked>> | 80% | 28,979 psi | 42% | 2218 fps | 98.6% |
| Norma MRP | <<locked>> | 80% | 49,052 psi | 70% | 2559 fps | 100% |
| Norma URP | <<locked>> | 80% | 58,015 psi | 83% | 2579 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 44,570 psi | 64% | 2500 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 80% | 56,956 psi | 82% | 2595 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 50,415 psi | 72% | 2641 fps | 95.2% |
| Ramshot Magnum | <<locked>> | 80% | 40,030 psi | 57% | 2388 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,298 psi | 42% | 1480 fps | 100% |
| ReloadSwiss RS 76 | 89.1 gr | 80% | 37,434 psi | 54% | 2434 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 34,316 psi | 49% | 2343 fps | 97.3% |
| Rottweil R 904 | <<locked>> | 80% | 50,662 psi | 73% | 2503 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 49,574 psi | 71% | 2513 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 49,719 psi | 71% | 2520 fps | 95.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 59,219 psi | 85% | 2559 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 57,827 psi | 83% | 2569 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 37,101 psi | 53% | 2346 fps | 95% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 58,015 psi | 83% | 2523 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 49,226 psi | 71% | 2510 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 51,605 psi | 74% | 2500 fps | 100% |
| Somchem S365 | <<locked>> | 80% | 55,999 psi | 80% | 2536 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,966 psi | 72% | 2487 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 98% | 52,315 psi | 75% | 2615 fps | 95.4% |
| Vihtavuori N165 | <<locked>> | 80% | 43,830 psi | 63% | 2388 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 39,929 psi | 57% | 2352 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 58,610 psi | 84% | 2575 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 49,734 psi | 71% | 2487 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 48,602 psi | 70% | 2562 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 80% | 40,553 psi | 58% | 2411 fps | 99.2% |
| Vihtavuori N568 | <<locked>> | 80% | 35,578 psi | 51% | 2356 fps | 97.1% |
| Vihtavuori N570 | 88.5 gr | 82% | 36,274 psi | 52% | 2402 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 58,668 psi | 84% | 2520 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 43,903 psi | 63% | 2497 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 46,166 psi | 66% | 2438 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 74 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 300gr | MAKER Expanding Subsonic. ADI AR 2218 delivers the highest muzzle velocity at 2,828 fps; across all powders the maximum-charge window runs from 1,621 fps to 2,828 fps. Accurate 8700 gives the best case fill at 100 %, and 74 of the 74 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 1:11.5 twist; slower twists will usually not stabilise this weight. Accurate 8700, 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. Vihtavuori N570, Hodgdon Retumbo, ReloadSwiss RS 76 rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 300gr | MAKER Expanding Subsonic they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Vihtavuori 20N29 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.