Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 350gr | MAKER SUB-REX bullet and 64 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N570, Alliant Reloder-33 and ADI AR 2218.
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% | 62,192 psi | 89% | 2415 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 49,182 psi | 71% | 2408 fps | 99.5% |
| Accurate MAGPRO | <<locked>> | 88% | 62,642 psi | 90% | 2556 fps | 100% |
| ADI APS 450 | <<locked>> | 82% | 61,743 psi | 89% | 1854 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 59,625 psi | 86% | 2454 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 62,468 psi | 90% | 2526 fps | 100% |
| ADI AR 2217 | <<locked>> | 96% | 61,641 psi | 89% | 2516 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 62,018 psi | 89% | 2671 fps | 100% |
| ADI AR 2225 | <<locked>> | 98% | 60,829 psi | 87% | 2536 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 62,932 psi | 90% | 2487 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 62,685 psi | 90% | 2516 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 60,771 psi | 87% | 2415 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 61,641 psi | 89% | 2493 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 61,975 psi | 89% | 2507 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 59,611 psi | 86% | 2589 fps | 100% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 59,030 psi | 85% | 2585 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 62,033 psi | 89% | 2503 fps | 100% |
| Bofors RP15 | <<locked>> | 90% | 61,989 psi | 89% | 2510 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 61,279 psi | 88% | 2530 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 62,685 psi | 90% | 2516 fps | 100% |
| Hodgdon 50BMGᴾ | <<locked>> | 100% | 61,931 psi | 89% | 2592 fps | 96.7% |
| Hodgdon H1000 | <<locked>> | 94% | 59,335 psi | 85% | 2487 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 60,930 psi | 88% | 2467 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 86% | 59,930 psi | 86% | 2457 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 59,915 psi | 86% | 2346 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 61,714 psi | 89% | 2589 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,101 psi | 55% | 1486 fps | 100% |
| Hodgdon US 869ᴾ | <<locked>> | 100% | 54,012 psi | 78% | 2464 fps | 97.4% |
| IMR 4350 | <<locked>> | 82% | 61,496 psi | 88% | 2411 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 60,524 psi | 87% | 2385 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 60,829 psi | 87% | 2441 fps | 100% |
| IMR 7828 SSC | <<locked>> | 86% | 60,901 psi | 87% | 2516 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 59,219 psi | 85% | 2421 fps | 99% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 59,321 psi | 85% | 2533 fps | 100% |
| Lovex D100 | <<locked>> | 96% | 60,147 psi | 86% | 2484 fps | 98.6% |
| Lovex S071 | <<locked>> | 92% | 60,147 psi | 86% | 2395 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 60,887 psi | 87% | 2543 fps | 100% |
| Norma MRP | <<locked>> | 84% | 59,146 psi | 85% | 2484 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 61,424 psi | 88% | 2523 fps | 100% |
| Ramshot LRTᴾ | <<locked>> | 100% | 61,279 psi | 88% | 2608 fps | 98.8% |
| Ramshot Magnum | <<locked>> | 88% | 62,671 psi | 90% | 2493 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,088 psi | 56% | 1519 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 62,569 psi | 90% | 2582 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 61,061 psi | 88% | 2575 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 59,828 psi | 86% | 2425 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 59,132 psi | 85% | 2438 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 96% | 60,147 psi | 86% | 2484 fps | 98.6% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 51,213 psi | 74% | 2415 fps | 99.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 62,613 psi | 90% | 2477 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 61,017 psi | 88% | 2425 fps | 100% |
| Somchem S365 | <<locked>> | 82% | 62,497 psi | 90% | 2398 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 59,146 psi | 85% | 2408 fps | 100% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 49,124 psi | 71% | 2411 fps | 98.3% |
| Vihtavuori 24N41ᴾ | <<locked>> | 100% | 62,105 psi | 89% | 2572 fps | 98.6% |
| Vihtavuori N150 | <<locked>> | 82% | 62,337 psi | 90% | 2323 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 61,163 psi | 88% | 2421 fps | 100% |
| Vihtavuori N170 | <<locked>> | 98% | 59,785 psi | 86% | 2480 fps | 99.8% |
| Vihtavuori N555 | <<locked>> | 86% | 62,584 psi | 90% | 2438 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 59,393 psi | 85% | 2513 fps | 100% |
| Vihtavuori N565 | <<locked>> | 90% | 59,219 psi | 85% | 2497 fps | 100% |
| Vihtavuori N568 | <<locked>> | 94% | 61,467 psi | 88% | 2572 fps | 100% |
| Vihtavuori N570 | <<locked>> | 94% | 59,393 psi | 85% | 2592 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 88% | 62,410 psi | 90% | 2510 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 60,060 psi | 86% | 2425 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% | 47,805 psi | 69% | 2251 fps | 100% |
| Accurate 8700 | <<locked>> | 88% | 31,836 psi | 46% | 2100 fps | 95.1% |
| Accurate MAGPRO | <<locked>> | 80% | 47,500 psi | 68% | 2359 fps | 99.9% |
| ADI APS 450 | <<locked>> | 80% | 59,567 psi | 86% | 1827 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 52,243 psi | 75% | 2362 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 47,529 psi | 68% | 2339 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 35,375 psi | 51% | 2146 fps | 99.6% |
| ADI AR 2218 | 85.5 gr | 82% | 32,227 psi | 46% | 2162 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 32,590 psi | 47% | 2133 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 52,069 psi | 75% | 2359 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 48,138 psi | 69% | 2336 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 47,036 psi | 68% | 2257 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 41,089 psi | 59% | 2238 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,635 psi | 77% | 2415 fps | 100% |
| Alliant Reloder-33 | 84.9 gr | 80% | 32,851 psi | 47% | 2156 fps | 96.3% |
| Alliant Reloder-50 | <<locked>> | 84% | 32,706 psi | 47% | 2156 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 45,049 psi | 65% | 2274 fps | 99.3% |
| Bofors RP15 | <<locked>> | 80% | 44,860 psi | 64% | 2287 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 38,290 psi | 55% | 2211 fps | 99.9% |
| Bofors RP5 | <<locked>> | 80% | 48,138 psi | 69% | 2336 fps | 100% |
| Hodgdon 50BMG | <<locked>> | 96% | 54,157 psi | 78% | 2487 fps | 95.1% |
| Hodgdon H1000 | <<locked>> | 80% | 36,361 psi | 52% | 2165 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 80% | 44,193 psi | 63% | 2244 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,950 psi | 70% | 2316 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 56,231 psi | 81% | 2306 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 40,335 psi | 58% | 2306 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,631 psi | 41% | 1325 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 46,862 psi | 67% | 2359 fps | 95.8% |
| IMR 4350 | <<locked>> | 80% | 57,682 psi | 83% | 2369 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 53,592 psi | 77% | 2306 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 50,328 psi | 72% | 2310 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 49,443 psi | 71% | 2372 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 40,321 psi | 58% | 2142 fps | 95.4% |
| IMR 8133 Enduron | <<locked>> | 80% | 30,182 psi | 43% | 2070 fps | 98.5% |
| Lovex D100 | <<locked>> | 88% | 45,208 psi | 65% | 2277 fps | 95.8% |
| Lovex S071 | <<locked>> | 80% | 41,205 psi | 59% | 2156 fps | 100% |
| Norma 217 | <<locked>> | 80% | 30,545 psi | 44% | 2090 fps | 99.8% |
| Norma MRP | <<locked>> | 80% | 51,459 psi | 74% | 2392 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 52,837 psi | 76% | 2421 fps | 100% |
| Ramshot LRT | <<locked>> | 92% | 46,238 psi | 66% | 2392 fps | 95.9% |
| Ramshot Magnum | <<locked>> | 80% | 46,195 psi | 66% | 2300 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,428 psi | 42% | 1355 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,479 psi | 57% | 2287 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 36,143 psi | 52% | 2211 fps | 99.1% |
| Rottweil R 904 | <<locked>> | 80% | 52,794 psi | 76% | 2339 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 51,851 psi | 74% | 2349 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 88% | 45,208 psi | 65% | 2277 fps | 95.8% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 33,953 psi | 49% | 2123 fps | 95.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 51,517 psi | 74% | 2349 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 53,621 psi | 77% | 2336 fps | 100% |
| Somchem S365 | <<locked>> | 80% | 58,450 psi | 84% | 2356 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 51,895 psi | 75% | 2320 fps | 100% |
| Vihtavuori 20N29 | <<locked>> | 94% | 39,378 psi | 57% | 2254 fps | 95.8% |
| Vihtavuori 24N41 | <<locked>> | 92% | 46,644 psi | 67% | 2359 fps | 95.7% |
| Vihtavuori N150 | <<locked>> | 80% | 58,610 psi | 84% | 2283 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 44,324 psi | 64% | 2215 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 36,013 psi | 52% | 2113 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 51,663 psi | 74% | 2316 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 48,573 psi | 70% | 2372 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 42,380 psi | 61% | 2264 fps | 100% |
| Vihtavuori N568 | <<locked>> | 80% | 37,434 psi | 54% | 2224 fps | 98.9% |
| Vihtavuori N570 | 82.5 gr | 80% | 35,766 psi | 51% | 2218 fps | 97% |
| Winchester StaBALL HD | <<locked>> | 80% | 46,543 psi | 67% | 2333 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 52,286 psi | 75% | 2333 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 64 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 350gr | MAKER SUB-REX. ADI AR 2218 delivers the highest muzzle velocity at 2,671 fps; across all powders the maximum-charge window runs from 1,486 fps to 2,671 fps. Accurate 8700 gives the best case fill at 100 %, and 64 of the 64 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 350.0 gr projectile in 0.338" calls for a 1:10.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 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, Alliant Reloder-33, ADI AR 2218 rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 350gr | MAKER SUB-REX 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.