Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 300gr | Nosler Custom Competition bullet and 57 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon H4831, ADI AR 2218 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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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 84% | 54,172 psi | 85% | 2526 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 48,530 psi | 76% | 2575 fps | 98.5% |
| Accurate High Country | <<locked>> | 82% | 56,028 psi | 88% | 2677 fps | 100% |
| Accurate MAGPRO | <<locked>> | 84% | 57,000 psi | 89% | 2690 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 55,187 psi | 86% | 2602 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 57,551 psi | 90% | 2677 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 56,536 psi | 89% | 2664 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 56,739 psi | 89% | 2802 fps | 99.9% |
| ADI AR 2225 | <<locked>> | 96% | 55,912 psi | 88% | 2687 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 82% | 55,390 psi | 87% | 2602 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 54,839 psi | 86% | 2595 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 84% | 54,346 psi | 85% | 2621 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 56,434 psi | 88% | 2575 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 56,913 psi | 89% | 2651 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 57,014 psi | 89% | 2661 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 54,723 psi | 86% | 2720 fps | 99.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 54,462 psi | 85% | 2717 fps | 99.4% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 57,493 psi | 90% | 2648 fps | 99.8% |
| Bofors RP15 | <<locked>> | 88% | 57,435 psi | 90% | 2661 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 56,652 psi | 89% | 2680 fps | 100% |
| Bofors RP5 | <<locked>> | 84% | 54,346 psi | 85% | 2621 fps | 100% |
| Hodgdon H1000 | <<locked>> | 90% | 54,244 psi | 85% | 2628 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 56,275 psi | 88% | 2612 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 84% | 55,274 psi | 87% | 2598 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 56,579 psi | 89% | 2743 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,985 psi | 60% | 1631 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 56,420 psi | 88% | 2589 fps | 100% |
| IMR 7828 SSC | <<locked>> | 86% | 56,188 psi | 88% | 2664 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 90% | 55,071 psi | 86% | 2556 fps | 97.4% |
| IMR 8133 Enduron | <<locked>> | 98% | 54,926 psi | 86% | 2677 fps | 100% |
| Lovex D100 | <<locked>> | 94% | 55,434 psi | 87% | 2605 fps | 96.6% |
| Lovex S071 | <<locked>> | 90% | 56,173 psi | 88% | 2552 fps | 100% |
| Norma 217 | <<locked>> | 98% | 56,391 psi | 88% | 2694 fps | 100% |
| Norma MRP | <<locked>> | 82% | 54,389 psi | 85% | 2631 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 57,551 psi | 90% | 2687 fps | 100% |
| Ramshot LRT | <<locked>> | 98% | 56,376 psi | 88% | 2733 fps | 96.7% |
| Ramshot Magnum | <<locked>> | 88% | 55,724 psi | 87% | 2618 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,030 psi | 61% | 1670 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 56,913 psi | 89% | 2730 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 55,970 psi | 88% | 2713 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 55,506 psi | 87% | 2575 fps | 100% |
| Rottweil R 905 | <<locked>> | 82% | 54,708 psi | 86% | 2589 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 94% | 55,434 psi | 87% | 2605 fps | 96.6% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 50,691 psi | 79% | 2585 fps | 98.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 54,346 psi | 85% | 2585 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 56,739 psi | 89% | 2572 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 54,853 psi | 86% | 2556 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 98% | 54,433 psi | 85% | 2648 fps | 95.9% |
| Vihtavuori N165 | <<locked>> | 86% | 54,911 psi | 86% | 2549 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 57,580 psi | 90% | 2644 fps | 99% |
| Vihtavuori N555 | <<locked>> | 82% | 54,607 psi | 86% | 2552 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 57,624 psi | 90% | 2694 fps | 100% |
| Vihtavuori N565 | <<locked>> | 88% | 55,085 psi | 86% | 2644 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 56,666 psi | 89% | 2717 fps | 100% |
| Vihtavuori N570 | <<locked>> | 92% | 54,070 psi | 85% | 2723 fps | 99.4% |
| Winchester StaBALL HD | <<locked>> | 86% | 57,087 psi | 89% | 2664 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 84% | 54,505 psi | 85% | 2559 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 47,543 psi | 75% | 2434 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 36,535 psi | 57% | 2352 fps | 95% |
| Accurate High Country | <<locked>> | 80% | 52,431 psi | 82% | 2628 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 49,632 psi | 78% | 2582 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 80% | 51,590 psi | 81% | 2552 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 46,992 psi | 74% | 2523 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 35,143 psi | 55% | 2306 fps | 98.6% |
| ADI AR 2218 | 99.1 gr | 86% | 36,912 psi | 58% | 2428 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 32,416 psi | 51% | 2287 fps | 99.8% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 51,880 psi | 81% | 2552 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 51,430 psi | 81% | 2546 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 47,732 psi | 75% | 2520 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 46,441 psi | 73% | 2441 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 40,596 psi | 64% | 2415 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 53,084 psi | 83% | 2608 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 35,201 psi | 55% | 2362 fps | 95.2% |
| Alliant Reloder-50 | <<locked>> | 88% | 37,840 psi | 59% | 2418 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 44,527 psi | 70% | 2444 fps | 98.2% |
| Bofors RP15 | <<locked>> | 80% | 44,469 psi | 70% | 2467 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 37,971 psi | 60% | 2375 fps | 99.2% |
| Bofors RP5 | <<locked>> | 80% | 47,732 psi | 75% | 2520 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 38,218 psi | 60% | 2369 fps | 99.6% |
| Hodgdon H4831 | 88 gr | 80% | 49,269 psi | 77% | 2510 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 48,501 psi | 76% | 2500 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 80% | 39,798 psi | 62% | 2480 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,660 psi | 45% | 1457 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,806 psi | 78% | 2493 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 45,774 psi | 72% | 2507 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 45,542 psi | 71% | 2405 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 80% | 29,979 psi | 47% | 2218 fps | 96.8% |
| Lovex D100 | <<locked>> | 92% | 51,721 psi | 81% | 2552 fps | 95.7% |
| Lovex S071 | <<locked>> | 80% | 41,162 psi | 65% | 2333 fps | 100% |
| Norma 217 | <<locked>> | 80% | 30,385 psi | 48% | 2241 fps | 98.9% |
| Norma MRP | <<locked>> | 80% | 50,865 psi | 80% | 2582 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 46,296 psi | 73% | 2523 fps | 100% |
| Ramshot LRT | <<locked>> | 96% | 52,562 psi | 82% | 2674 fps | 95.8% |
| Ramshot Magnum | <<locked>> | 80% | 41,655 psi | 65% | 2411 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,399 psi | 46% | 1493 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 39,073 psi | 61% | 2457 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 35,868 psi | 56% | 2365 fps | 97.6% |
| Rottweil R 904 | <<locked>> | 80% | 52,141 psi | 82% | 2526 fps | 100% |
| Rottweil R 905 | <<locked>> | 80% | 51,314 psi | 80% | 2539 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 92% | 51,721 psi | 81% | 2552 fps | 95.7% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 38,754 psi | 61% | 2375 fps | 95.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 50,966 psi | 80% | 2536 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 53,127 psi | 83% | 2523 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 51,576 psi | 81% | 2513 fps | 100% |
| Vihtavuori 24N41 | <<locked>> | 96% | 50,879 psi | 80% | 2592 fps | 95% |
| Vihtavuori N165 | <<locked>> | 80% | 45,223 psi | 71% | 2411 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 41,350 psi | 65% | 2379 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 51,256 psi | 80% | 2507 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 50,328 psi | 79% | 2589 fps | 100% |
| Vihtavuori N565 | <<locked>> | 80% | 42,163 psi | 66% | 2438 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 80% | 37,086 psi | 58% | 2379 fps | 97.5% |
| Vihtavuori N570 | 92.5 gr | 82% | 37,913 psi | 59% | 2431 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 45,876 psi | 72% | 2516 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 47,674 psi | 75% | 2461 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 57 powders for .338-378 Weath. Mag. loaded with the .338 | 300gr | Nosler Custom Competition. ADI AR 2218 delivers the highest muzzle velocity at 2,802 fps; across all powders the maximum-charge window runs from 1,631 fps to 2,802 fps. Accurate 8700 gives the best case fill at 100 %, and 57 of the 57 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 60–90 %, 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, Hodgdon TrailBoss, ReloadSwiss RS 14 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 H4831, ADI AR 2218, Vihtavuori N570 rank at the top here: for .338-378 Weath. Mag. with the .338 | 300gr | Nosler Custom Competition 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.