Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 225gr | NorthFork Bonded Core bullet and 66 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ReloadSwiss RS 76 and ReloadSwiss RS 80.
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>> | 90% | 56,565 psi | 89% | 2933 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 57,188 psi | 90% | 2956 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 55,376 psi | 87% | 3041 fps | 99.1% |
| ADI AR 2209 | <<locked>> | 86% | 54,201 psi | 85% | 2966 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 90% | 56,130 psi | 88% | 3038 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 98% | 54,505 psi | 85% | 3005 fps | 99.8% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 50,836 psi | 80% | 3038 fps | 96.8% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 52,765 psi | 83% | 3025 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 54,491 psi | 85% | 2956 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 57,551 psi | 90% | 3012 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 90% | 56,521 psi | 89% | 3031 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 54,491 psi | 85% | 2940 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 54,346 psi | 85% | 3009 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 54,911 psi | 86% | 3028 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 56,014 psi | 88% | 3097 fps | 98% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 57,014 psi | 89% | 2995 fps | 98.2% |
| Bofors RP15 | <<locked>> | 92% | 55,709 psi | 87% | 3018 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 54,172 psi | 85% | 3018 fps | 99.8% |
| Bofors RP5 | <<locked>> | 90% | 56,521 psi | 89% | 3031 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 56,072 psi | 88% | 3028 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 55,521 psi | 87% | 2969 fps | 99.3% |
| Hodgdon H4831 SC | <<locked>> | 88% | 54,563 psi | 86% | 2953 fps | 99.2% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 54,679 psi | 86% | 2877 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 57,101 psi | 89% | 3153 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,579 psi | 59% | 1890 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 56,753 psi | 89% | 2940 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 57,305 psi | 90% | 2943 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 56,115 psi | 88% | 2949 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 90% | 54,360 psi | 85% | 3015 fps | 99.6% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 48,312 psi | 76% | 2940 fps | 99.2% |
| Lovex S065 | <<locked>> | 82% | 57,072 psi | 89% | 2917 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 55,448 psi | 87% | 2920 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 54,462 psi | 85% | 2904 fps | 100% |
| Norma 204 | <<locked>> | 82% | 54,244 psi | 85% | 2943 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 49,110 psi | 77% | 2966 fps | 100% |
| Norma MRP | <<locked>> | 88% | 56,637 psi | 89% | 3048 fps | 100% |
| Norma URP | <<locked>> | 82% | 55,259 psi | 87% | 2933 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 55,419 psi | 87% | 3038 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 82% | 54,172 psi | 85% | 2943 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 53,867 psi | 84% | 2966 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,435 psi | 60% | 1932 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 57,334 psi | 90% | 2979 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 55,767 psi | 87% | 3005 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 53,853 psi | 84% | 3081 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 57,551 psi | 90% | 3107 fps | 99.5% |
| Rottweil R 904 | <<locked>> | 86% | 55,129 psi | 86% | 2936 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 88% | 57,246 psi | 90% | 3002 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 57,072 psi | 89% | 2917 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 55,448 psi | 87% | 2920 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 56,101 psi | 88% | 2874 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 56,840 psi | 89% | 2999 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 56,434 psi | 88% | 2927 fps | 99.4% |
| Somchem S365 | <<locked>> | 84% | 56,449 psi | 88% | 2936 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 57,682 psi | 90% | 2972 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 56,913 psi | 89% | 2923 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 57,450 psi | 90% | 2956 fps | 100% |
| Vihtavuori N170 | <<locked>> | 96% | 56,391 psi | 88% | 2969 fps | 96.4% |
| Vihtavuori N550 | <<locked>> | 82% | 56,072 psi | 88% | 2930 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 56,536 psi | 89% | 2969 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 56,130 psi | 88% | 3051 fps | 99.5% |
| Vihtavuori N565 | <<locked>> | 94% | 56,666 psi | 89% | 3035 fps | 99.7% |
| Vihtavuori N568 | <<locked>> | 96% | 53,998 psi | 85% | 3041 fps | 98.8% |
| Vihtavuori N570 | <<locked>> | 98% | 54,998 psi | 86% | 3104 fps | 97.5% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 56,362 psi | 88% | 2874 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 57,725 psi | 90% | 3081 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 57,479 psi | 90% | 2969 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% | 40,350 psi | 63% | 2657 fps | 99.6% |
| Accurate 4350 | <<locked>> | 80% | 53,301 psi | 84% | 2897 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 41,698 psi | 65% | 2782 fps | 96.2% |
| ADI AR 2209 | <<locked>> | 80% | 44,295 psi | 69% | 2789 fps | 98.8% |
| ADI AR 2213 | <<locked>> | 80% | 39,769 psi | 62% | 2726 fps | 96.8% |
| ADI AR 2217 | <<locked>> | 86% | 36,230 psi | 57% | 2641 fps | 95.9% |
| ADI AR 2218 | <<locked>> | 98% | 47,311 psi | 74% | 2963 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 82% | 28,906 psi | 45% | 2484 fps | 95.7% |
| Alliant Reloder-16 | <<locked>> | 80% | 50,937 psi | 80% | 2904 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 44,280 psi | 69% | 2782 fps | 98.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 40,379 psi | 63% | 2736 fps | 98.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 39,015 psi | 61% | 2680 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 33,678 psi | 53% | 2608 fps | 99.2% |
| Alliant Reloder-26 | <<locked>> | 80% | 43,874 psi | 69% | 2844 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 44,628 psi | 70% | 2890 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 44,266 psi | 69% | 2759 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 37,492 psi | 59% | 2667 fps | 97.2% |
| Bofors RP30 | <<locked>> | 82% | 33,533 psi | 53% | 2598 fps | 95.1% |
| Bofors RP5 | <<locked>> | 80% | 40,379 psi | 63% | 2736 fps | 98.2% |
| Hodgdon H1000 | <<locked>> | 82% | 34,432 psi | 54% | 2598 fps | 95.8% |
| Hodgdon H4831 | <<locked>> | 80% | 42,351 psi | 66% | 2730 fps | 96.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 41,611 psi | 65% | 2713 fps | 96.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 47,950 psi | 75% | 2779 fps | 100% |
| Hodgdon Retumbo | 92.8 gr | 80% | 32,967 psi | 52% | 2641 fps | 96.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,166 psi | 44% | 1690 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 49,995 psi | 78% | 2835 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 50,328 psi | 79% | 2841 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 43,526 psi | 68% | 2723 fps | 97.3% |
| IMR 7828 SSC | <<locked>> | 80% | 38,493 psi | 60% | 2707 fps | 96.4% |
| IMR 8133 Enduron | <<locked>> | 90% | 34,301 psi | 54% | 2635 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 53,563 psi | 84% | 2864 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 52,025 psi | 82% | 2864 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 34,751 psi | 54% | 2536 fps | 98.7% |
| Norma 204 | <<locked>> | 80% | 50,807 psi | 80% | 2887 fps | 99.6% |
| Norma 217 | <<locked>> | 86% | 30,168 psi | 47% | 2543 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 42,699 psi | 67% | 2808 fps | 99.5% |
| Norma URP | <<locked>> | 80% | 51,750 psi | 81% | 2881 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 38,290 psi | 60% | 2713 fps | 96.8% |
| Ramshot Hunter | <<locked>> | 80% | 50,821 psi | 80% | 2887 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 34,301 psi | 54% | 2592 fps | 97.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,877 psi | 45% | 1732 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 53,563 psi | 84% | 2923 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 51,924 psi | 81% | 2949 fps | 100% |
| ReloadSwiss RS 76 | 99.3 gr | 80% | 32,111 psi | 50% | 2612 fps | 97.3% |
| ReloadSwiss RS 80 | 110.1 gr | 88% | 39,218 psi | 61% | 2766 fps | 95.7% |
| Rottweil R 904 | <<locked>> | 80% | 45,310 psi | 71% | 2762 fps | 98.2% |
| Rottweil R 905 | <<locked>> | 80% | 43,801 psi | 69% | 2772 fps | 98.9% |
| Shooters World Long Rifle | <<locked>> | 80% | 53,563 psi | 84% | 2864 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 52,025 psi | 82% | 2864 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 52,605 psi | 82% | 2818 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 43,468 psi | 68% | 2766 fps | 98.8% |
| Somchem S361 | <<locked>> | 80% | 46,311 psi | 73% | 2753 fps | 97.8% |
| Somchem S365 | <<locked>> | 80% | 49,313 psi | 77% | 2835 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 44,411 psi | 70% | 2749 fps | 99.4% |
| Vihtavuori N160 | <<locked>> | 80% | 53,171 psi | 83% | 2871 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,580 psi | 60% | 2625 fps | 98.2% |
| Vihtavuori N170 | <<locked>> | 94% | 52,707 psi | 83% | 2910 fps | 95.6% |
| Vihtavuori N550 | <<locked>> | 80% | 52,620 psi | 82% | 2877 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 43,497 psi | 68% | 2756 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 42,525 psi | 67% | 2799 fps | 97.1% |
| Vihtavuori N565 | <<locked>> | 82% | 37,637 psi | 59% | 2671 fps | 95.8% |
| Vihtavuori N568 | <<locked>> | 88% | 40,466 psi | 63% | 2782 fps | 95.4% |
| Vihtavuori N570 | <<locked>> | 94% | 47,601 psi | 75% | 2966 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 52,605 psi | 82% | 2825 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 36,477 psi | 57% | 2730 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 40,785 psi | 64% | 2677 fps | 98.2% |
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 66 powders for .338-378 Weath. Mag. loaded with the .338 | 225gr | NorthFork Bonded Core. Hodgdon Retumbo delivers the highest muzzle velocity at 3,153 fps; across all powders the maximum-charge window runs from 1,890 fps to 3,153 fps. ADI AR 2218 gives the best case fill at 100 %, and 66 of the 66 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 225.0 gr projectile in 0.338" calls for a 1:15.0 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, Alliant Reloder-33 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, ReloadSwiss RS 76, ReloadSwiss RS 80 rank at the top here: for .338-378 Weath. Mag. with the .338 | 225gr | NorthFork Bonded Core 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.