Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 250gr | Nosler Custom Competition bullet and 64 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Vihtavuori N570 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: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 88% | 54,520 psi | 85% | 2766 fps | 100% |
| Accurate High Country | <<locked>> | 86% | 56,217 psi | 88% | 2923 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 57,130 psi | 90% | 2930 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 86% | 55,883 psi | 88% | 2848 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 54,186 psi | 85% | 2867 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 98% | 56,391 psi | 88% | 2897 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 52,562 psi | 82% | 2946 fps | 98.2% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,679 psi | 86% | 2917 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 56,057 psi | 88% | 2844 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 56,057 psi | 88% | 2844 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 56,260 psi | 88% | 2831 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 55,492 psi | 87% | 2841 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 54,650 psi | 86% | 2861 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 56,376 psi | 88% | 2822 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 56,376 psi | 88% | 2894 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 56,913 psi | 89% | 2907 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 53,911 psi | 84% | 2933 fps | 98.4% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 49,269 psi | 77% | 2851 fps | 97% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 54,839 psi | 86% | 2828 fps | 98.5% |
| Bofors RP15 | <<locked>> | 92% | 57,479 psi | 90% | 2904 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 56,043 psi | 88% | 2910 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 54,650 psi | 86% | 2861 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 53,940 psi | 85% | 2861 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 57,159 psi | 90% | 2854 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 88% | 56,173 psi | 88% | 2841 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 56,318 psi | 88% | 2753 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 55,332 psi | 87% | 2979 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,681 psi | 59% | 1781 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 54,737 psi | 86% | 2769 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 55,317 psi | 87% | 2769 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 57,624 psi | 90% | 2831 fps | 99.8% |
| IMR 7828 SSC | <<locked>> | 90% | 56,347 psi | 88% | 2904 fps | 100% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 50,111 psi | 79% | 2838 fps | 99.8% |
| Lovex S070 | <<locked>> | 82% | 56,898 psi | 89% | 2795 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,173 psi | 88% | 2785 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,927 psi | 88% | 2828 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 51,126 psi | 80% | 2864 fps | 100% |
| Norma MRP | <<locked>> | 86% | 54,505 psi | 85% | 2874 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,840 psi | 89% | 2808 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 57,537 psi | 90% | 2927 fps | 100% |
| Ramshot Hunter | <<locked>> | 82% | 55,912 psi | 88% | 2825 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 55,709 psi | 87% | 2854 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,624 psi | 61% | 1824 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 57,580 psi | 90% | 2884 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 55,985 psi | 88% | 2969 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 55,303 psi | 87% | 2936 fps | 99.7% |
| Rottweil R 904 | <<locked>> | 86% | 56,594 psi | 89% | 2818 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 86% | 55,245 psi | 87% | 2831 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 56,898 psi | 89% | 2795 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,406 psi | 90% | 2749 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 54,853 psi | 86% | 2828 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 54,346 psi | 85% | 2759 fps | 99.5% |
| Somchem S365 | <<locked>> | 82% | 54,549 psi | 85% | 2762 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,666 psi | 87% | 2802 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 55,390 psi | 87% | 2785 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 54,302 psi | 85% | 2808 fps | 96.9% |
| Vihtavuori N550 | <<locked>> | 82% | 57,682 psi | 90% | 2808 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 54,766 psi | 86% | 2799 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 54,056 psi | 85% | 2877 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 92% | 54,824 psi | 86% | 2871 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 96% | 55,985 psi | 88% | 2940 fps | 99.5% |
| Vihtavuori N570 | <<locked>> | 98% | 57,058 psi | 89% | 2999 fps | 98.6% |
| Winchester StaBALL HD | <<locked>> | 90% | 56,043 psi | 88% | 2910 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 55,274 psi | 87% | 2799 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% | 41,756 psi | 65% | 2559 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 45,745 psi | 72% | 2746 fps | 99.1% |
| Accurate MAGPRO | <<locked>> | 80% | 43,192 psi | 68% | 2687 fps | 97.6% |
| ADI AR 2209 | <<locked>> | 80% | 45,861 psi | 72% | 2687 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 80% | 41,104 psi | 64% | 2631 fps | 98.1% |
| ADI AR 2217 | <<locked>> | 82% | 32,721 psi | 51% | 2438 fps | 95.6% |
| ADI AR 2218 | <<locked>> | 94% | 42,351 psi | 66% | 2740 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 80% | 28,036 psi | 44% | 2352 fps | 96.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 46,137 psi | 72% | 2684 fps | 99.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 46,137 psi | 72% | 2684 fps | 99.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,620 psi | 82% | 2782 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,701 psi | 72% | 2677 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,800 psi | 66% | 2638 fps | 99.1% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,538 psi | 64% | 2575 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,056 psi | 55% | 2523 fps | 99.8% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,571 psi | 71% | 2740 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 43,047 psi | 67% | 2736 fps | 95.7% |
| Alliant Reloder-50 | <<locked>> | 98% | 45,716 psi | 72% | 2785 fps | 96% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 42,598 psi | 67% | 2602 fps | 95.6% |
| Bofors RP15 | <<locked>> | 80% | 38,914 psi | 61% | 2575 fps | 98.4% |
| Bofors RP30 | <<locked>> | 80% | 32,503 psi | 51% | 2454 fps | 95.8% |
| Bofors RP5 | <<locked>> | 80% | 41,800 psi | 66% | 2638 fps | 99.1% |
| Hodgdon H1000 | <<locked>> | 80% | 33,272 psi | 52% | 2454 fps | 96.5% |
| Hodgdon H4831 | <<locked>> | 80% | 43,714 psi | 69% | 2631 fps | 98.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,917 psi | 67% | 2615 fps | 97.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,617 psi | 78% | 2661 fps | 100% |
| Hodgdon Retumbo | 88.5 gr | 80% | 34,171 psi | 54% | 2559 fps | 98.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,311 psi | 44% | 1594 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,561 psi | 81% | 2720 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 52,011 psi | 82% | 2723 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,875 psi | 70% | 2621 fps | 98.4% |
| IMR 7828 SSC | <<locked>> | 80% | 39,798 psi | 62% | 2615 fps | 97.8% |
| IMR 8133 Enduron | <<locked>> | 86% | 31,270 psi | 49% | 2441 fps | 95% |
| Lovex S070 | <<locked>> | 80% | 53,592 psi | 84% | 2749 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 36,042 psi | 56% | 2444 fps | 99.5% |
| Norma 204 | <<locked>> | 80% | 52,243 psi | 82% | 2772 fps | 99.9% |
| Norma 217 | <<locked>> | 82% | 27,470 psi | 43% | 2352 fps | 95.5% |
| Norma MRP | <<locked>> | 80% | 44,295 psi | 69% | 2707 fps | 99.9% |
| Norma URP | <<locked>> | 80% | 53,403 psi | 84% | 2762 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,726 psi | 62% | 2621 fps | 98.2% |
| Ramshot Hunter | <<locked>> | 80% | 52,286 psi | 82% | 2772 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,636 psi | 56% | 2507 fps | 98.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,964 psi | 45% | 1631 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,693 psi | 84% | 2831 fps | 100% |
| ReloadSwiss RS 76 | 94.7 gr | 80% | 33,272 psi | 52% | 2533 fps | 98.8% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 35,172 psi | 55% | 2552 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 46,746 psi | 73% | 2657 fps | 99.1% |
| Rottweil R 905 | <<locked>> | 80% | 45,382 psi | 71% | 2671 fps | 99.6% |
| Shooters World SW4350 | <<locked>> | 80% | 53,592 psi | 84% | 2749 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,853 psi | 84% | 2700 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 45,034 psi | 71% | 2664 fps | 99.5% |
| Somchem S361 | <<locked>> | 80% | 47,616 psi | 75% | 2651 fps | 98.7% |
| Somchem S365 | <<locked>> | 80% | 51,155 psi | 80% | 2717 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,774 psi | 72% | 2644 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 80% | 39,885 psi | 63% | 2526 fps | 99.1% |
| Vihtavuori N170 | <<locked>> | 90% | 47,427 psi | 74% | 2694 fps | 95.2% |
| Vihtavuori N550 | <<locked>> | 80% | 53,998 psi | 85% | 2756 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,078 psi | 71% | 2651 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 44,063 psi | 69% | 2700 fps | 98.3% |
| Vihtavuori N565 | <<locked>> | 80% | 36,477 psi | 57% | 2526 fps | 96.5% |
| Vihtavuori N568 | <<locked>> | 84% | 36,564 psi | 57% | 2572 fps | 95.1% |
| Vihtavuori N570 | 103.3 gr | 90% | 42,830 psi | 67% | 2743 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 38,276 psi | 60% | 2635 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 42,032 psi | 66% | 2579 fps | 99.1% |
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 .338-378 Weath. Mag. loaded with the .338 | 250gr | Nosler Custom Competition. Vihtavuori N570 delivers the highest muzzle velocity at 2,999 fps; across all powders the maximum-charge window runs from 1,781 fps to 2,999 fps. ADI AR 2218 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 (440 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 250.0 gr projectile in 0.338" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, 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. Hodgdon Retumbo, Vihtavuori N570, ReloadSwiss RS 76 rank at the top here: for .338-378 Weath. Mag. with the .338 | 250gr | 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.