Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 225gr | Barnes TTSX BT bullet and 75 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% | 56,536 psi | 89% | 2933 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 57,421 psi | 90% | 2959 fps | 100% |
| Accurate High Country | <<locked>> | 88% | 54,549 psi | 85% | 3038 fps | 99.6% |
| Accurate MAGPRO | <<locked>> | 90% | 55,550 psi | 87% | 3041 fps | 99% |
| ADI AR 2209 | <<locked>> | 88% | 54,795 psi | 86% | 2972 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 92% | 56,594 psi | 89% | 3041 fps | 99.7% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 54,665 psi | 86% | 3005 fps | 99.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 49,023 psi | 77% | 2966 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 54,911 psi | 86% | 2969 fps | 99.9% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 54,911 psi | 86% | 2969 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 84% | 54,911 psi | 86% | 2963 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 54,302 psi | 85% | 2963 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 92% | 56,768 psi | 89% | 3035 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 54,578 psi | 86% | 2943 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 54,317 psi | 85% | 3012 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 54,926 psi | 86% | 3031 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 51,474 psi | 81% | 3022 fps | 96.9% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 57,696 psi | 90% | 2999 fps | 98.1% |
| Bofors RP15 | <<locked>> | 94% | 55,883 psi | 88% | 3018 fps | 99.9% |
| Bofors RP30 | <<locked>> | 98% | 53,925 psi | 85% | 3018 fps | 99.7% |
| Bofors RP5 | <<locked>> | 92% | 56,768 psi | 89% | 3035 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 55,550 psi | 87% | 2907 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 56,289 psi | 88% | 3031 fps | 100% |
| Hodgdon H414 | <<locked>> | 82% | 55,245 psi | 87% | 2963 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 57,653 psi | 90% | 2976 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 56,130 psi | 88% | 2972 fps | 99.2% |
| Hodgdon H4831 SC | <<locked>> | 90% | 54,955 psi | 86% | 2956 fps | 99.1% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 55,114 psi | 86% | 2884 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 56,855 psi | 89% | 3150 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 56,043 psi | 88% | 3002 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,275 psi | 58% | 1870 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 57,580 psi | 90% | 2949 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 57,029 psi | 89% | 2930 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 54,143 psi | 85% | 2897 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 56,840 psi | 89% | 2956 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 92% | 54,578 psi | 86% | 3018 fps | 99.5% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 44,469 psi | 70% | 2871 fps | 98.4% |
| Lovex S065 | <<locked>> | 84% | 57,638 psi | 90% | 2923 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 56,072 psi | 88% | 2927 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 57,725 psi | 90% | 2949 fps | 100% |
| Norma 204 | <<locked>> | 84% | 54,955 psi | 86% | 2953 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 44,846 psi | 70% | 2894 fps | 99.7% |
| Norma MRP | <<locked>> | 90% | 56,753 psi | 89% | 3054 fps | 100% |
| Norma URP | <<locked>> | 84% | 55,811 psi | 87% | 2943 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 55,463 psi | 87% | 3041 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 84% | 54,694 psi | 86% | 2949 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 53,896 psi | 84% | 2969 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,087 psi | 60% | 1916 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 57,595 psi | 90% | 2982 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 56,376 psi | 88% | 3015 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 53,766 psi | 84% | 3081 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 57,159 psi | 90% | 3104 fps | 99.4% |
| Rottweil R 904 | <<locked>> | 88% | 55,593 psi | 87% | 2940 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 90% | 57,595 psi | 90% | 3005 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 55,550 psi | 87% | 2907 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 57,638 psi | 90% | 2923 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 56,072 psi | 88% | 2927 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 56,869 psi | 89% | 2881 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 57,217 psi | 90% | 3005 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 57,188 psi | 90% | 2933 fps | 99.3% |
| Somchem S365 | <<locked>> | 86% | 56,753 psi | 89% | 2943 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 54,273 psi | 85% | 2920 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 57,537 psi | 90% | 2933 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 54,070 psi | 85% | 2904 fps | 100% |
| Vihtavuori N170 | <<locked>> | 98% | 56,608 psi | 89% | 2969 fps | 96.2% |
| Vihtavuori N550 | <<locked>> | 84% | 56,608 psi | 89% | 2936 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 56,434 psi | 88% | 2969 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 56,391 psi | 88% | 3054 fps | 99.4% |
| Vihtavuori N565 | <<locked>> | 96% | 56,521 psi | 89% | 3035 fps | 99.6% |
| Vihtavuori N568 | <<locked>> | 98% | 53,766 psi | 84% | 3038 fps | 98.6% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 54,694 psi | 86% | 3097 fps | 97.2% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 57,116 psi | 90% | 2884 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 55,405 psi | 87% | 2966 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 57,348 psi | 90% | 3081 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 54,085 psi | 85% | 2917 fps | 99.8% |
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% | 37,260 psi | 58% | 2598 fps | 99.1% |
| Accurate 4350 | <<locked>> | 80% | 49,893 psi | 78% | 2848 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 40,930 psi | 64% | 2776 fps | 97.1% |
| Accurate MAGPRO | 97 gr | 82% | 41,524 psi | 65% | 2779 fps | 95.9% |
| ADI AR 2209 | <<locked>> | 80% | 41,611 psi | 65% | 2733 fps | 98.2% |
| ADI AR 2213 | <<locked>> | 80% | 37,130 psi | 58% | 2664 fps | 95.6% |
| ADI AR 2217 | <<locked>> | 88% | 36,114 psi | 57% | 2638 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 84% | 28,442 psi | 45% | 2470 fps | 95.1% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 42,032 psi | 66% | 2736 fps | 98.2% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 42,032 psi | 66% | 2736 fps | 98.2% |
| Alliant Reloder-16 | <<locked>> | 80% | 48,051 psi | 75% | 2858 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 41,640 psi | 65% | 2730 fps | 98.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 37,492 psi | 59% | 2674 fps | 97.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 36,187 psi | 57% | 2625 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 31,140 psi | 49% | 2543 fps | 98.3% |
| Alliant Reloder-26 | <<locked>> | 80% | 40,277 psi | 63% | 2779 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 47,674 psi | 75% | 2949 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 44,773 psi | 70% | 2766 fps | 95% |
| Bofors RP15 | <<locked>> | 80% | 34,867 psi | 55% | 2605 fps | 96.1% |
| Bofors RP30 | <<locked>> | 86% | 35,346 psi | 55% | 2648 fps | 95.6% |
| Bofors RP5 | <<locked>> | 80% | 37,492 psi | 59% | 2674 fps | 97.2% |
| Bofors RP7 | <<locked>> | 80% | 52,054 psi | 82% | 2851 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 84% | 34,301 psi | 54% | 2592 fps | 95.5% |
| Hodgdon H414 | <<locked>> | 80% | 51,605 psi | 81% | 2904 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 54,085 psi | 85% | 2920 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 80% | 39,711 psi | 62% | 2671 fps | 95.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 38,972 psi | 61% | 2654 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 45,107 psi | 71% | 2730 fps | 100% |
| Hodgdon Retumbo | 91.7 gr | 82% | 32,561 psi | 51% | 2628 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 51,953 psi | 81% | 2936 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,905 psi | 44% | 1673 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 47,413 psi | 74% | 2785 fps | 99.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 53,548 psi | 84% | 2877 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 47,282 psi | 74% | 2792 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 41,147 psi | 64% | 2671 fps | 96.5% |
| IMR 7828 SSC | <<locked>> | 80% | 35,781 psi | 56% | 2641 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 94% | 35,955 psi | 56% | 2680 fps | 95.7% |
| Lovex S065 | <<locked>> | 80% | 50,908 psi | 80% | 2822 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 49,313 psi | 77% | 2818 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 31,966 psi | 50% | 2470 fps | 97.7% |
| Norma 204 | <<locked>> | 80% | 47,848 psi | 75% | 2831 fps | 99.1% |
| Norma 217 | <<locked>> | 88% | 29,269 psi | 46% | 2520 fps | 95% |
| Norma MRP | <<locked>> | 80% | 39,494 psi | 62% | 2743 fps | 98.9% |
| Norma URP | <<locked>> | 80% | 48,907 psi | 77% | 2835 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 35,346 psi | 55% | 2644 fps | 95.4% |
| Ramshot Hunter | <<locked>> | 80% | 47,761 psi | 75% | 2838 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 31,531 psi | 49% | 2523 fps | 95.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,572 psi | 45% | 1716 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 50,169 psi | 79% | 2871 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 48,559 psi | 76% | 2897 fps | 100% |
| ReloadSwiss RS 76 | 95.8 gr | 80% | 29,414 psi | 46% | 2530 fps | 95.6% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 38,595 psi | 60% | 2756 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 42,873 psi | 67% | 2713 fps | 97.5% |
| Rottweil R 905 | <<locked>> | 80% | 40,959 psi | 64% | 2713 fps | 98.2% |
| Rottweil R 907 | <<locked>> | 80% | 52,054 psi | 82% | 2851 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 80% | 50,908 psi | 80% | 2822 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 49,313 psi | 77% | 2818 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 49,777 psi | 78% | 2772 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 40,640 psi | 64% | 2707 fps | 98.1% |
| Somchem S361 | <<locked>> | 80% | 43,569 psi | 68% | 2697 fps | 97% |
| Somchem S365 | <<locked>> | 80% | 46,093 psi | 72% | 2785 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 41,466 psi | 65% | 2694 fps | 98.9% |
| Vihtavuori N160 | <<locked>> | 80% | 50,299 psi | 79% | 2828 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 35,984 psi | 56% | 2566 fps | 97.2% |
| Vihtavuori N170 | <<locked>> | 96% | 52,837 psi | 83% | 2910 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 49,647 psi | 78% | 2831 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 40,379 psi | 63% | 2703 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 39,508 psi | 62% | 2733 fps | 96% |
| Vihtavuori N565 | <<locked>> | 84% | 37,173 psi | 58% | 2664 fps | 95.4% |
| Vihtavuori N568 | <<locked>> | 90% | 40,132 psi | 63% | 2776 fps | 95.1% |
| Vihtavuori N570 | <<locked>> | 96% | 47,210 psi | 74% | 2959 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 49,647 psi | 78% | 2782 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 51,750 psi | 81% | 2907 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 32,851 psi | 51% | 2657 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 38,058 psi | 60% | 2621 fps | 97.3% |
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 75 powders for .338-378 Weath. Mag. loaded with the .338 | 225gr | Barnes TTSX BT. Hodgdon Retumbo delivers the highest muzzle velocity at 3,150 fps; across all powders the maximum-charge window runs from 1,870 fps to 3,150 fps. ADI AR 2217 gives the best case fill at 100 %, and 75 of the 75 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 225.0 gr projectile in 0.338" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, 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, Accurate MAGPRO rank at the top here: for .338-378 Weath. Mag. with the .338 | 225gr | Barnes TTSX BT 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.