Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 230gr | Nosler CT FailSafe 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% | 56,826 psi | 89% | 2907 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 57,276 psi | 90% | 2927 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 55,564 psi | 87% | 3015 fps | 99.2% |
| ADI AR 2209 | <<locked>> | 86% | 54,534 psi | 85% | 2940 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 90% | 56,449 psi | 88% | 3012 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 98% | 54,766 psi | 86% | 2979 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 51,068 psi | 80% | 3015 fps | 97.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 53,084 psi | 83% | 3002 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 54,694 psi | 86% | 2930 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 57,740 psi | 90% | 2986 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 90% | 56,797 psi | 89% | 3005 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 54,708 psi | 86% | 2913 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 54,563 psi | 86% | 2982 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 55,245 psi | 87% | 3002 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 56,173 psi | 88% | 3074 fps | 98.2% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 57,072 psi | 89% | 2969 fps | 98.3% |
| Bofors RP15 | <<locked>> | 92% | 55,985 psi | 88% | 2992 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 54,404 psi | 85% | 2995 fps | 99.8% |
| Bofors RP5 | <<locked>> | 90% | 56,797 psi | 89% | 3005 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 56,333 psi | 88% | 3005 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 55,709 psi | 87% | 2943 fps | 99.4% |
| Hodgdon H4831 SC | <<locked>> | 88% | 54,737 psi | 86% | 2927 fps | 99.3% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 54,911 psi | 86% | 2848 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 57,392 psi | 90% | 3123 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,550 psi | 59% | 1864 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 57,014 psi | 89% | 2917 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 57,595 psi | 90% | 2917 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 56,304 psi | 88% | 2920 fps | 99.5% |
| IMR 7828 SSC | <<locked>> | 90% | 54,636 psi | 86% | 2992 fps | 99.7% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 48,544 psi | 76% | 2917 fps | 99.3% |
| Lovex S065 | <<locked>> | 82% | 57,246 psi | 90% | 2890 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 55,637 psi | 87% | 2890 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 54,694 psi | 86% | 2877 fps | 100% |
| Norma 204 | <<locked>> | 82% | 54,505 psi | 85% | 2920 fps | 99.9% |
| Norma 217ᴾ | <<locked>> | 100% | 49,226 psi | 77% | 2943 fps | 100% |
| Norma MRP | <<locked>> | 88% | 56,768 psi | 89% | 3022 fps | 100% |
| Norma URP | <<locked>> | 82% | 55,477 psi | 87% | 2907 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 55,637 psi | 87% | 3012 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 82% | 54,462 psi | 85% | 2917 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 54,143 psi | 85% | 2943 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,421 psi | 60% | 1906 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 57,479 psi | 90% | 2949 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 55,970 psi | 88% | 2976 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 54,186 psi | 85% | 3054 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 57,667 psi | 90% | 3081 fps | 99.6% |
| Rottweil R 904 | <<locked>> | 86% | 55,216 psi | 87% | 2907 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 88% | 57,435 psi | 90% | 2976 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 57,246 psi | 90% | 2890 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 55,637 psi | 87% | 2890 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 56,144 psi | 88% | 2844 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 57,029 psi | 89% | 2972 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 56,710 psi | 89% | 2900 fps | 99.5% |
| Somchem S365 | <<locked>> | 84% | 56,768 psi | 89% | 2910 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 54,244 psi | 85% | 2890 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 56,985 psi | 89% | 2894 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 57,595 psi | 90% | 2927 fps | 100% |
| Vihtavuori N170 | <<locked>> | 96% | 56,695 psi | 89% | 2946 fps | 96.6% |
| Vihtavuori N550 | <<locked>> | 82% | 56,333 psi | 88% | 2904 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 56,695 psi | 89% | 2940 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 56,289 psi | 88% | 3025 fps | 99.6% |
| Vihtavuori N565 | <<locked>> | 94% | 56,927 psi | 89% | 3012 fps | 99.7% |
| Vihtavuori N568 | <<locked>> | 96% | 54,201 psi | 85% | 3015 fps | 98.9% |
| Vihtavuori N570 | <<locked>> | 98% | 55,216 psi | 87% | 3077 fps | 97.7% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 56,579 psi | 89% | 2848 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 53,940 psi | 85% | 2999 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 53,998 psi | 85% | 2887 fps | 99.9% |
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% | 40,611 psi | 64% | 2638 fps | 99.7% |
| Accurate 4350 | <<locked>> | 80% | 53,650 psi | 84% | 2874 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 41,843 psi | 66% | 2759 fps | 96.5% |
| ADI AR 2209 | <<locked>> | 80% | 44,585 psi | 70% | 2766 fps | 99% |
| ADI AR 2213 | <<locked>> | 80% | 39,943 psi | 63% | 2703 fps | 97% |
| ADI AR 2217 | <<locked>> | 84% | 34,026 psi | 53% | 2559 fps | 95.1% |
| ADI AR 2218 | <<locked>> | 98% | 47,529 psi | 74% | 2946 fps | 96% |
| ADI AR 2225 | <<locked>> | 82% | 29,066 psi | 46% | 2467 fps | 96.1% |
| Alliant Reloder-16 | <<locked>> | 80% | 51,256 psi | 80% | 2877 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 44,585 psi | 70% | 2762 fps | 99% |
| Alliant Reloder-22 | <<locked>> | 80% | 40,567 psi | 64% | 2713 fps | 98.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 39,305 psi | 62% | 2657 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 33,924 psi | 53% | 2592 fps | 99.3% |
| Alliant Reloder-26 | <<locked>> | 80% | 44,077 psi | 69% | 2818 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 44,846 psi | 70% | 2867 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 44,411 psi | 70% | 2736 fps | 95.3% |
| Bofors RP15 | <<locked>> | 80% | 37,739 psi | 59% | 2648 fps | 97.5% |
| Bofors RP30 | <<locked>> | 82% | 33,620 psi | 53% | 2575 fps | 95.3% |
| Bofors RP5 | <<locked>> | 80% | 40,567 psi | 64% | 2713 fps | 98.4% |
| Hodgdon H1000 | <<locked>> | 80% | 32,314 psi | 51% | 2516 fps | 95% |
| Hodgdon H4831 | <<locked>> | 80% | 42,424 psi | 66% | 2703 fps | 97.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 41,785 psi | 65% | 2690 fps | 96.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,225 psi | 76% | 2753 fps | 100% |
| Hodgdon Retumbo | 91.7 gr | 80% | 33,127 psi | 52% | 2621 fps | 96.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,152 psi | 44% | 1667 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,314 psi | 79% | 2808 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 50,662 psi | 79% | 2815 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 43,787 psi | 69% | 2700 fps | 97.6% |
| IMR 7828 SSC | <<locked>> | 80% | 38,653 psi | 61% | 2684 fps | 96.7% |
| IMR 8133 Enduron | <<locked>> | 90% | 34,476 psi | 54% | 2618 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 53,838 psi | 84% | 2841 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 52,344 psi | 82% | 2838 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 34,954 psi | 55% | 2513 fps | 98.8% |
| Norma 204 | <<locked>> | 80% | 50,865 psi | 80% | 2858 fps | 99.7% |
| Norma 217 | <<locked>> | 86% | 30,269 psi | 47% | 2523 fps | 96.1% |
| Norma MRP | <<locked>> | 80% | 42,830 psi | 67% | 2782 fps | 99.6% |
| Norma URP | <<locked>> | 80% | 52,054 psi | 82% | 2858 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 38,377 psi | 60% | 2690 fps | 97% |
| Ramshot Hunter | <<locked>> | 80% | 50,894 psi | 80% | 2861 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 34,447 psi | 54% | 2572 fps | 97.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,877 psi | 45% | 1709 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 53,664 psi | 84% | 2894 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 52,112 psi | 82% | 2920 fps | 100% |
| ReloadSwiss RS 76 | 98.1 gr | 80% | 32,227 psi | 51% | 2592 fps | 97.6% |
| ReloadSwiss RS 80 | 108.8 gr | 88% | 39,421 psi | 62% | 2746 fps | 96% |
| Rottweil R 904 | <<locked>> | 80% | 45,600 psi | 71% | 2743 fps | 98.4% |
| Rottweil R 905 | <<locked>> | 80% | 44,092 psi | 69% | 2749 fps | 99% |
| Shooters World Long Rifle | <<locked>> | 80% | 53,838 psi | 84% | 2841 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 52,344 psi | 82% | 2838 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 52,750 psi | 83% | 2792 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 43,772 psi | 69% | 2746 fps | 99% |
| Somchem S361 | <<locked>> | 80% | 46,398 psi | 73% | 2730 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 49,690 psi | 78% | 2808 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 44,599 psi | 70% | 2726 fps | 99.5% |
| Vihtavuori N160 | <<locked>> | 80% | 53,519 psi | 84% | 2844 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,856 psi | 61% | 2602 fps | 98.4% |
| Vihtavuori N170 | <<locked>> | 94% | 52,968 psi | 83% | 2887 fps | 95.8% |
| Vihtavuori N550 | <<locked>> | 80% | 52,692 psi | 83% | 2848 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 43,772 psi | 69% | 2733 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 42,627 psi | 67% | 2776 fps | 97.3% |
| Vihtavuori N565 | <<locked>> | 80% | 35,259 psi | 55% | 2589 fps | 95.1% |
| Vihtavuori N568 | <<locked>> | 88% | 40,756 psi | 64% | 2762 fps | 95.8% |
| Vihtavuori N570 | <<locked>> | 94% | 47,906 psi | 75% | 2946 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 52,750 psi | 83% | 2795 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 36,608 psi | 57% | 2707 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 40,857 psi | 64% | 2654 fps | 98.3% |
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 66 powders for .338-378 Weath. Mag. loaded with the .338 | 230gr | Nosler CT FailSafe. Hodgdon Retumbo delivers the highest muzzle velocity at 3,123 fps; across all powders the maximum-charge window runs from 1,864 fps to 3,123 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 230.0 gr projectile in 0.338" calls for a 1:14.5 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 | 230gr | Nosler CT FailSafe 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.