Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 240gr | NorthFork Bonded Core bullet and 71 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 Winchester StaBALL HD.
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.
A valid access license is required to use the Personalized Load Calculator.
You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 90% | 54,230 psi | 85% | 2805 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 54,998 psi | 86% | 2825 fps | 100% |
| Accurate MAGPRO | <<locked>> | 90% | 56,666 psi | 89% | 2966 fps | 99.4% |
| ADI AR 2209 | <<locked>> | 88% | 55,854 psi | 88% | 2894 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 57,667 psi | 90% | 2963 fps | 99.8% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 55,724 psi | 87% | 2930 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 48,254 psi | 76% | 2894 fps | 96.2% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 50,111 psi | 79% | 2894 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 56,028 psi | 88% | 2877 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 55,419 psi | 87% | 2881 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 90% | 54,273 psi | 85% | 2900 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 55,695 psi | 87% | 2861 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 55,332 psi | 87% | 2930 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 56,231 psi | 88% | 2953 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 52,605 psi | 82% | 2956 fps | 97.5% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 54,882 psi | 86% | 2864 fps | 97.9% |
| Bofors RP15 | <<locked>> | 94% | 57,043 psi | 89% | 2943 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 55,114 psi | 86% | 2943 fps | 99.9% |
| Bofors RP5 | <<locked>> | 90% | 54,273 psi | 85% | 2900 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 56,565 psi | 89% | 2825 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 57,290 psi | 90% | 2953 fps | 100% |
| Hodgdon H414 | <<locked>> | 82% | 56,449 psi | 88% | 2881 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 57,217 psi | 90% | 2897 fps | 99.5% |
| Hodgdon H4831 SC | <<locked>> | 90% | 56,144 psi | 88% | 2881 fps | 99.4% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 56,275 psi | 88% | 2802 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 54,186 psi | 85% | 3012 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 57,116 psi | 90% | 2920 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,507 psi | 59% | 1798 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 55,085 psi | 86% | 2815 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 55,419 psi | 87% | 2818 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 54,346 psi | 85% | 2822 fps | 99.3% |
| IMR 7828 SSC | <<locked>> | 92% | 55,825 psi | 87% | 2943 fps | 99.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 45,658 psi | 72% | 2808 fps | 98.9% |
| Lovex S065 | <<locked>> | 82% | 55,303 psi | 87% | 2792 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 57,246 psi | 90% | 2844 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 55,579 psi | 87% | 2825 fps | 100% |
| Norma 204 | <<locked>> | 84% | 56,115 psi | 88% | 2874 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 46,166 psi | 72% | 2835 fps | 99.9% |
| Norma MRP | <<locked>> | 88% | 54,157 psi | 85% | 2917 fps | 100% |
| Norma URP | <<locked>> | 84% | 56,985 psi | 89% | 2861 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 56,681 psi | 89% | 2963 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 84% | 55,912 psi | 88% | 2871 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 55,129 psi | 86% | 2894 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,421 psi | 60% | 1841 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 55,143 psi | 86% | 2848 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 57,537 psi | 90% | 2933 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 54,810 psi | 86% | 3002 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 54,114 psi | 85% | 2966 fps | 99.3% |
| Rottweil R 904 | <<locked>> | 88% | 56,724 psi | 89% | 2861 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 88% | 55,071 psi | 86% | 2874 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 56,565 psi | 89% | 2825 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 55,303 psi | 87% | 2792 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 57,246 psi | 90% | 2844 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 54,288 psi | 85% | 2746 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 54,665 psi | 86% | 2871 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 54,476 psi | 85% | 2799 fps | 99.2% |
| Somchem S365 | <<locked>> | 84% | 54,375 psi | 85% | 2812 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 55,477 psi | 87% | 2844 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 54,911 psi | 86% | 2799 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 55,143 psi | 86% | 2825 fps | 100% |
| Vihtavuori N170 | <<locked>> | 98% | 57,682 psi | 90% | 2897 fps | 96.8% |
| Vihtavuori N550 | <<locked>> | 82% | 54,157 psi | 85% | 2805 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 54,317 psi | 85% | 2841 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 57,609 psi | 90% | 2979 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 94% | 54,172 psi | 85% | 2907 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 98% | 55,013 psi | 86% | 2969 fps | 99% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 55,869 psi | 88% | 3028 fps | 97.8% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 54,201 psi | 85% | 2753 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 56,623 psi | 89% | 2884 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 54,433 psi | 85% | 2949 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 55,274 psi | 87% | 2838 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% | 38,783 psi | 61% | 2543 fps | 99.6% |
| Accurate 4350 | <<locked>> | 80% | 51,430 psi | 81% | 2776 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 39,914 psi | 63% | 2661 fps | 96% |
| ADI AR 2209 | <<locked>> | 80% | 42,699 psi | 67% | 2667 fps | 98.7% |
| ADI AR 2213 | <<locked>> | 80% | 38,174 psi | 60% | 2605 fps | 96.5% |
| ADI AR 2217 | <<locked>> | 86% | 34,795 psi | 55% | 2523 fps | 95.6% |
| ADI AR 2218 | <<locked>> | 98% | 44,976 psi | 70% | 2825 fps | 95% |
| ADI AR 2225 | <<locked>> | 82% | 27,731 psi | 43% | 2372 fps | 95.4% |
| Alliant Reloder-16 | <<locked>> | 80% | 49,211 psi | 77% | 2779 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 42,743 psi | 67% | 2664 fps | 98.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 38,667 psi | 61% | 2615 fps | 98% |
| Alliant Reloder-23 | <<locked>> | 80% | 37,478 psi | 59% | 2569 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 32,300 psi | 51% | 2497 fps | 99% |
| Alliant Reloder-26 | <<locked>> | 80% | 41,713 psi | 65% | 2720 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 45,339 psi | 71% | 2822 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 45,585 psi | 71% | 2697 fps | 95.7% |
| Bofors RP15 | <<locked>> | 80% | 36,042 psi | 56% | 2552 fps | 97.1% |
| Bofors RP30 | <<locked>> | 84% | 34,156 psi | 54% | 2539 fps | 95.8% |
| Bofors RP5 | <<locked>> | 80% | 38,667 psi | 61% | 2615 fps | 98% |
| Bofors RP7 | <<locked>> | 80% | 53,098 psi | 83% | 2772 fps | 100% |
| Hodgdon H1000 | <<locked>> | 82% | 33,098 psi | 52% | 2484 fps | 95.5% |
| Hodgdon H414 | <<locked>> | 80% | 52,794 psi | 83% | 2828 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 40,770 psi | 64% | 2608 fps | 96.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 40,016 psi | 63% | 2592 fps | 96.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 46,296 psi | 73% | 2657 fps | 100% |
| Hodgdon Retumbo | 85.4 gr | 80% | 31,604 psi | 50% | 2523 fps | 96.2% |
| Hodgdon Superformance | <<locked>> | 80% | 53,040 psi | 83% | 2861 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,079 psi | 44% | 1608 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 48,428 psi | 76% | 2710 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 48,588 psi | 76% | 2717 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 42,134 psi | 66% | 2605 fps | 97.2% |
| IMR 7828 SSC | <<locked>> | 80% | 36,941 psi | 58% | 2589 fps | 96.2% |
| IMR 8133 Enduron | <<locked>> | 92% | 34,867 psi | 55% | 2575 fps | 95.9% |
| Lovex S065 | <<locked>> | 80% | 52,127 psi | 82% | 2743 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 50,517 psi | 79% | 2743 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 33,475 psi | 52% | 2425 fps | 98.6% |
| Norma 204 | <<locked>> | 80% | 49,008 psi | 77% | 2762 fps | 99.5% |
| Norma 217 | <<locked>> | 86% | 28,660 psi | 45% | 2428 fps | 95.4% |
| Norma MRP | <<locked>> | 80% | 40,785 psi | 64% | 2684 fps | 99.4% |
| Norma URP | <<locked>> | 80% | 50,111 psi | 79% | 2759 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 36,622 psi | 57% | 2592 fps | 96.5% |
| Ramshot Hunter | <<locked>> | 80% | 48,979 psi | 77% | 2766 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 32,706 psi | 51% | 2474 fps | 97% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,834 psi | 45% | 1647 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 51,547 psi | 81% | 2799 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 49,690 psi | 78% | 2818 fps | 100% |
| ReloadSwiss RS 76 | 91.4 gr | 80% | 30,647 psi | 48% | 2493 fps | 97% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 37,057 psi | 58% | 2641 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 43,888 psi | 69% | 2644 fps | 98.1% |
| Rottweil R 905 | <<locked>> | 80% | 42,293 psi | 66% | 2651 fps | 98.8% |
| Rottweil R 907 | <<locked>> | 80% | 53,098 psi | 83% | 2772 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 52,127 psi | 82% | 2743 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 50,517 psi | 79% | 2743 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 50,966 psi | 80% | 2697 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 41,959 psi | 66% | 2648 fps | 98.7% |
| Somchem S361 | <<locked>> | 80% | 44,628 psi | 70% | 2631 fps | 97.6% |
| Somchem S365 | <<locked>> | 80% | 47,413 psi | 74% | 2713 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 42,728 psi | 67% | 2631 fps | 99.3% |
| Vihtavuori N160 | <<locked>> | 80% | 51,459 psi | 81% | 2749 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 37,188 psi | 58% | 2510 fps | 98% |
| Vihtavuori N170 | <<locked>> | 94% | 50,459 psi | 79% | 2782 fps | 95.2% |
| Vihtavuori N550 | <<locked>> | 80% | 50,720 psi | 79% | 2753 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 41,771 psi | 65% | 2638 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 40,727 psi | 64% | 2677 fps | 96.9% |
| Vihtavuori N565 | <<locked>> | 82% | 35,998 psi | 56% | 2556 fps | 95.6% |
| Vihtavuori N568 | <<locked>> | 88% | 38,522 psi | 60% | 2657 fps | 95.1% |
| Vihtavuori N570 | <<locked>> | 94% | 45,092 psi | 71% | 2831 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 50,749 psi | 80% | 2703 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 52,953 psi | 83% | 2828 fps | 100% |
| Winchester StaBALL HD | 87.7 gr | 80% | 34,330 psi | 54% | 2612 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 39,131 psi | 61% | 2559 fps | 98% |
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 71 powders for .338-378 Weath. Mag. loaded with the .338 | 240gr | NorthFork Bonded Core. Vihtavuori N570 delivers the highest muzzle velocity at 3,028 fps; across all powders the maximum-charge window runs from 1,798 fps to 3,028 fps. ADI AR 2217 gives the best case fill at 100 %, and 71 of the 71 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 240.0 gr projectile in 0.338" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2218, ADI AR 2225 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, Winchester StaBALL HD rank at the top here: for .338-378 Weath. Mag. with the .338 | 240gr | 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.