Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 200gr | NorthFork Bonded Core bullet and 73 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 Accurate MAGPRO.
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>> | 92% | 56,681 psi | 89% | 3087 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 57,537 psi | 90% | 3120 fps | 100% |
| Accurate High Country | <<locked>> | 88% | 54,505 psi | 85% | 3189 fps | 99.1% |
| Accurate MAGPRO | <<locked>> | 90% | 55,579 psi | 87% | 3192 fps | 98.4% |
| ADI AR 2209 | <<locked>> | 88% | 54,563 psi | 86% | 3123 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 92% | 56,391 psi | 88% | 3192 fps | 99.2% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 54,534 psi | 85% | 3153 fps | 99.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 49,081 psi | 77% | 3110 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 54,853 psi | 86% | 3120 fps | 99.6% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 54,853 psi | 86% | 3120 fps | 99.6% |
| Alliant Reloder-16 | <<locked>> | 84% | 54,737 psi | 86% | 3123 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 54,230 psi | 85% | 3110 fps | 99.5% |
| Alliant Reloder-22 | <<locked>> | 92% | 56,695 psi | 89% | 3186 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 92% | 54,520 psi | 85% | 3100 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 54,041 psi | 85% | 3163 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 54,868 psi | 86% | 3186 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 57,580 psi | 90% | 3146 fps | 97.3% |
| Bofors RP15 | <<locked>> | 94% | 55,869 psi | 88% | 3173 fps | 99.7% |
| Bofors RP30 | <<locked>> | 98% | 53,882 psi | 84% | 3163 fps | 99.3% |
| Bofors RP5 | <<locked>> | 92% | 56,695 psi | 89% | 3186 fps | 99.8% |
| Bofors RP7 | <<locked>> | 82% | 55,419 psi | 87% | 3064 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 98% | 56,275 psi | 88% | 3182 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 82% | 55,129 psi | 86% | 3117 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 57,551 psi | 90% | 3133 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 90% | 55,999 psi | 88% | 3123 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 90% | 54,897 psi | 86% | 3104 fps | 98.5% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 54,940 psi | 86% | 3041 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 56,884 psi | 89% | 3307 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 55,956 psi | 88% | 3156 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,260 psi | 58% | 1998 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 57,421 psi | 90% | 3107 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 56,869 psi | 89% | 3087 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 54,070 psi | 85% | 3054 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 56,739 psi | 89% | 3107 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 92% | 54,462 psi | 85% | 3169 fps | 99% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 44,556 psi | 70% | 3009 fps | 97.6% |
| Lovex S065 | <<locked>> | 84% | 57,696 psi | 90% | 3084 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 56,043 psi | 88% | 3081 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 54,491 psi | 85% | 3054 fps | 100% |
| Norma 204 | <<locked>> | 84% | 54,853 psi | 86% | 3107 fps | 99.5% |
| Norma 217ᴾ | <<locked>> | 100% | 45,005 psi | 71% | 3038 fps | 99.3% |
| Norma MRP | <<locked>> | 90% | 56,739 psi | 89% | 3209 fps | 100% |
| Norma URP | <<locked>> | 84% | 55,709 psi | 87% | 3104 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 55,332 psi | 87% | 3192 fps | 99.4% |
| Ramshot Hunter | <<locked>> | 84% | 54,665 psi | 86% | 3107 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 53,969 psi | 85% | 3117 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,174 psi | 60% | 2047 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 57,667 psi | 90% | 3143 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 56,217 psi | 88% | 3173 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 53,766 psi | 84% | 3232 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 57,363 psi | 90% | 3251 fps | 98.9% |
| Rottweil R 904 | <<locked>> | 88% | 55,506 psi | 87% | 3091 fps | 99% |
| Rottweil R 905 | <<locked>> | 90% | 57,609 psi | 90% | 3163 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 82% | 55,419 psi | 87% | 3064 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 84% | 57,696 psi | 90% | 3084 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 56,043 psi | 88% | 3081 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 56,855 psi | 89% | 3035 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 57,174 psi | 90% | 3159 fps | 99.8% |
| Somchem S361 | <<locked>> | 88% | 57,232 psi | 90% | 3081 fps | 98.8% |
| Somchem S365 | <<locked>> | 86% | 56,666 psi | 89% | 3104 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 54,288 psi | 85% | 3071 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 84% | 57,406 psi | 90% | 3091 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 54,027 psi | 85% | 3051 fps | 99.8% |
| Vihtavuori N550 | <<locked>> | 84% | 56,579 psi | 89% | 3097 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 56,536 psi | 89% | 3130 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 56,362 psi | 88% | 3205 fps | 98.9% |
| Vihtavuori N565 | <<locked>> | 96% | 56,666 psi | 89% | 3186 fps | 99.1% |
| Vihtavuori N568 | <<locked>> | 98% | 53,882 psi | 84% | 3186 fps | 97.9% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 54,679 psi | 86% | 3241 fps | 96.2% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 56,971 psi | 89% | 3038 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 55,463 psi | 87% | 3123 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 57,188 psi | 90% | 3241 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 54,157 psi | 85% | 3068 fps | 99.5% |
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% | 37,768 psi | 59% | 2740 fps | 98.5% |
| Accurate 4350 | <<locked>> | 80% | 50,212 psi | 79% | 3005 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 41,118 psi | 64% | 2920 fps | 96.1% |
| Accurate MAGPRO | 105.5 gr | 84% | 44,715 psi | 70% | 2982 fps | 95.9% |
| ADI AR 2209 | <<locked>> | 80% | 41,611 psi | 65% | 2874 fps | 97.3% |
| ADI AR 2213 | <<locked>> | 82% | 39,929 psi | 63% | 2864 fps | 95.5% |
| ADI AR 2217 | <<locked>> | 90% | 38,754 psi | 61% | 2828 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 86% | 30,763 psi | 48% | 2657 fps | 95.1% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 42,148 psi | 66% | 2877 fps | 97.4% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 42,148 psi | 66% | 2877 fps | 97.4% |
| Alliant Reloder-16 | <<locked>> | 80% | 47,906 psi | 75% | 3012 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 41,756 psi | 65% | 2871 fps | 97.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 37,652 psi | 59% | 2808 fps | 96.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 36,303 psi | 57% | 2766 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 31,386 psi | 49% | 2674 fps | 97.3% |
| Alliant Reloder-26 | <<locked>> | 80% | 40,379 psi | 63% | 2923 fps | 99.8% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 50,894 psi | 80% | 3022 fps | 95.7% |
| Bofors RP15 | <<locked>> | 80% | 34,969 psi | 55% | 2736 fps | 95% |
| Bofors RP30 | <<locked>> | 88% | 38,159 psi | 60% | 2844 fps | 95.6% |
| Bofors RP5 | <<locked>> | 80% | 37,652 psi | 59% | 2808 fps | 96.2% |
| Bofors RP7 | <<locked>> | 80% | 52,040 psi | 82% | 3005 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 86% | 36,912 psi | 58% | 2785 fps | 95.4% |
| Hodgdon H414 | <<locked>> | 80% | 51,576 psi | 81% | 3058 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 80% | 53,954 psi | 85% | 3074 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 82% | 42,598 psi | 67% | 2871 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 82% | 41,858 psi | 66% | 2854 fps | 95.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 45,179 psi | 71% | 2884 fps | 100% |
| Hodgdon Retumbo | 99.8 gr | 84% | 35,114 psi | 55% | 2828 fps | 95.9% |
| Hodgdon Superformance | <<locked>> | 80% | 51,851 psi | 81% | 3087 fps | 99.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,992 psi | 44% | 1791 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 47,369 psi | 74% | 2933 fps | 99.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 53,330 psi | 84% | 3031 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 47,427 psi | 74% | 2943 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 41,205 psi | 65% | 2808 fps | 95.5% |
| IMR 7828 SSC | <<locked>> | 82% | 38,450 psi | 60% | 2838 fps | 95% |
| IMR 8133 Enduron | <<locked>> | 96% | 38,885 psi | 61% | 2881 fps | 95.7% |
| Lovex S065 | <<locked>> | 80% | 50,981 psi | 80% | 2976 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 49,342 psi | 77% | 2969 fps | 99.8% |
| Lovex S071 | <<locked>> | 80% | 32,445 psi | 51% | 2608 fps | 96.9% |
| Norma 204 | <<locked>> | 80% | 47,790 psi | 75% | 2976 fps | 98.5% |
| Norma 217 | <<locked>> | 90% | 31,850 psi | 50% | 2713 fps | 95.1% |
| Norma MRP | <<locked>> | 80% | 39,668 psi | 62% | 2884 fps | 98.2% |
| Norma URP | <<locked>> | 80% | 48,820 psi | 77% | 2989 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 38,232 psi | 60% | 2844 fps | 95.4% |
| Ramshot Hunter | <<locked>> | 80% | 47,732 psi | 75% | 2986 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 82% | 34,243 psi | 54% | 2717 fps | 95.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,631 psi | 45% | 1834 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 50,256 psi | 79% | 3028 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 48,457 psi | 76% | 3048 fps | 100% |
| ReloadSwiss RS 76 | 104.3 gr | 82% | 32,039 psi | 50% | 2726 fps | 95.7% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 42,076 psi | 66% | 2963 fps | 95.3% |
| Rottweil R 904 | <<locked>> | 80% | 42,844 psi | 67% | 2851 fps | 96.6% |
| Rottweil R 905 | <<locked>> | 80% | 41,089 psi | 64% | 2854 fps | 97.4% |
| Rottweil R 907 | <<locked>> | 80% | 52,040 psi | 82% | 3005 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 50,981 psi | 80% | 2976 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 49,342 psi | 77% | 2969 fps | 99.8% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 49,980 psi | 78% | 2923 fps | 99.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 40,756 psi | 64% | 2851 fps | 97.2% |
| Somchem S361 | <<locked>> | 80% | 43,729 psi | 69% | 2835 fps | 96.1% |
| Somchem S365 | <<locked>> | 80% | 46,122 psi | 72% | 2940 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 41,713 psi | 65% | 2835 fps | 98.2% |
| Vihtavuori N160 | <<locked>> | 80% | 50,372 psi | 79% | 2982 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 36,245 psi | 57% | 2700 fps | 96.3% |
| Vihtavuori N550 | <<locked>> | 80% | 49,661 psi | 78% | 2986 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 40,611 psi | 64% | 2851 fps | 100% |
| Vihtavuori N560 | <<locked>> | 82% | 42,482 psi | 67% | 2936 fps | 95.9% |
| Vihtavuori N565 | <<locked>> | 86% | 40,219 psi | 63% | 2867 fps | 95.4% |
| Vihtavuori N568 | <<locked>> | 92% | 43,381 psi | 68% | 2979 fps | 95.1% |
| Vihtavuori N570 | <<locked>> | 98% | 50,937 psi | 80% | 3173 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 49,574 psi | 78% | 2930 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 51,764 psi | 81% | 3061 fps | 99.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 32,909 psi | 52% | 2799 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 38,174 psi | 60% | 2753 fps | 96.3% |
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 73 powders for .338-378 Weath. Mag. loaded with the .338 | 200gr | NorthFork Bonded Core. Hodgdon Retumbo delivers the highest muzzle velocity at 3,307 fps; across all powders the maximum-charge window runs from 1,998 fps to 3,307 fps. ADI AR 2217 gives the best case fill at 100 %, and 73 of the 73 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 58–90 %, leaving at least 10 % headroom. The 200.0 gr projectile in 0.338" calls for a 1:17.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Hodgdon TrailBoss 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, Accurate MAGPRO rank at the top here: for .338-378 Weath. Mag. with the .338 | 200gr | 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.