Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 155gr | Frontier RSBT bullet and 61 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Vihtavuori N570 and ReloadSwiss RS 76.
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>> | 88% | 54,563 psi | 86% | 3205 fps | 100% |
| Accurate High Country | <<locked>> | 86% | 56,362 psi | 88% | 3373 fps | 99.4% |
| Accurate MAGPRO | <<locked>> | 88% | 57,319 psi | 90% | 3376 fps | 98.9% |
| ADI AR 2209 | <<locked>> | 86% | 55,883 psi | 88% | 3304 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 88% | 54,172 psi | 85% | 3310 fps | 99.2% |
| ADI AR 2217 | <<locked>> | 98% | 56,652 psi | 89% | 3340 fps | 99.7% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 53,243 psi | 83% | 3376 fps | 96.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 55,376 psi | 87% | 3366 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 56,072 psi | 88% | 3297 fps | 99.8% |
| Alliant Reloder-16 | <<locked>> | 82% | 55,869 psi | 88% | 3294 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 55,463 psi | 87% | 3291 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 88% | 54,665 psi | 86% | 3307 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 90% | 56,405 psi | 88% | 3274 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 56,637 psi | 89% | 3346 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 57,174 psi | 90% | 3366 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 54,766 psi | 86% | 3363 fps | 97% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 55,027 psi | 86% | 3261 fps | 97.2% |
| Bofors RP15 | <<locked>> | 92% | 57,711 psi | 90% | 3356 fps | 99.9% |
| Bofors RP30 | <<locked>> | 96% | 56,463 psi | 88% | 3356 fps | 99.7% |
| Bofors RP5 | <<locked>> | 88% | 54,665 psi | 86% | 3307 fps | 99.8% |
| Hodgdon H1000 | <<locked>> | 94% | 54,331 psi | 85% | 3304 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 88% | 57,217 psi | 90% | 3301 fps | 99.1% |
| Hodgdon H4831 SC | <<locked>> | 88% | 56,188 psi | 88% | 3284 fps | 99% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 56,115 psi | 88% | 3209 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 55,506 psi | 87% | 3435 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,550 psi | 59% | 2142 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 54,563 psi | 86% | 3215 fps | 99.9% |
| IMR 4831 | <<locked>> | 82% | 55,143 psi | 86% | 3222 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 57,653 psi | 90% | 3281 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 90% | 56,304 psi | 88% | 3356 fps | 99.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 50,589 psi | 79% | 3261 fps | 99% |
| Lovex S070 | <<locked>> | 82% | 56,724 psi | 89% | 3251 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,246 psi | 88% | 3232 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,738 psi | 87% | 3278 fps | 99.7% |
| Norma 217ᴾ | <<locked>> | 100% | 51,459 psi | 81% | 3294 fps | 100% |
| Norma MRP | <<locked>> | 86% | 54,694 psi | 86% | 3323 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,666 psi | 89% | 3268 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 57,696 psi | 90% | 3379 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 82% | 55,724 psi | 87% | 3278 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 56,202 psi | 88% | 3301 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,435 psi | 60% | 2192 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 57,595 psi | 90% | 3346 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 56,565 psi | 89% | 3422 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 56,159 psi | 88% | 3376 fps | 98.9% |
| Rottweil R 904 | <<locked>> | 86% | 56,420 psi | 88% | 3264 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 86% | 55,172 psi | 86% | 3278 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 82% | 56,724 psi | 89% | 3251 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,276 psi | 90% | 3199 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 54,839 psi | 86% | 3278 fps | 99.8% |
| Somchem S361 | <<locked>> | 84% | 54,389 psi | 85% | 3192 fps | 98.7% |
| Somchem S365 | <<locked>> | 82% | 54,331 psi | 85% | 3215 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,535 psi | 87% | 3245 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 55,550 psi | 87% | 3228 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 82% | 57,522 psi | 90% | 3264 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 54,607 psi | 86% | 3248 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 54,230 psi | 85% | 3323 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 92% | 55,100 psi | 86% | 3310 fps | 99.1% |
| Vihtavuori N568 | <<locked>> | 96% | 56,507 psi | 89% | 3376 fps | 98.6% |
| Vihtavuori N570 | <<locked>> | 96% | 53,606 psi | 84% | 3366 fps | 96.3% |
| Winchester StaBALL HD | <<locked>> | 90% | 56,101 psi | 88% | 3363 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 55,506 psi | 87% | 3241 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% | 41,597 psi | 65% | 2959 fps | 99.4% |
| Accurate High Country | <<locked>> | 80% | 45,571 psi | 71% | 3159 fps | 97.6% |
| Accurate MAGPRO | <<locked>> | 80% | 43,018 psi | 67% | 3084 fps | 95.6% |
| ADI AR 2209 | <<locked>> | 80% | 45,542 psi | 71% | 3104 fps | 98.5% |
| ADI AR 2213 | <<locked>> | 80% | 40,770 psi | 64% | 3028 fps | 96.1% |
| ADI AR 2217 | <<locked>> | 86% | 37,289 psi | 58% | 2930 fps | 95.2% |
| ADI AR 2218 | <<locked>> | 98% | 49,545 psi | 78% | 3294 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 84% | 31,923 psi | 50% | 2822 fps | 96.2% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 45,948 psi | 72% | 3104 fps | 98.5% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,199 psi | 82% | 3235 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,513 psi | 71% | 3097 fps | 98.5% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,452 psi | 65% | 3035 fps | 97.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,190 psi | 63% | 2982 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,766 psi | 54% | 2897 fps | 98.7% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,556 psi | 71% | 3159 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 50,763 psi | 80% | 3287 fps | 96% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 48,414 psi | 76% | 3127 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 38,624 psi | 61% | 2963 fps | 96.6% |
| Bofors RP30 | <<locked>> | 84% | 37,159 psi | 58% | 2946 fps | 95.4% |
| Bofors RP5 | <<locked>> | 80% | 41,452 psi | 65% | 3035 fps | 97.6% |
| Hodgdon H1000 | <<locked>> | 82% | 35,447 psi | 56% | 2881 fps | 95.1% |
| Hodgdon H4831 | <<locked>> | 80% | 43,410 psi | 68% | 3031 fps | 96.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,612 psi | 67% | 3012 fps | 96% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,240 psi | 77% | 3097 fps | 100% |
| Hodgdon Retumbo | 90 gr | 80% | 33,953 psi | 53% | 2923 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,079 psi | 44% | 1919 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,198 psi | 80% | 3156 fps | 99.8% |
| IMR 4831 | <<locked>> | 80% | 51,648 psi | 81% | 3163 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,599 psi | 70% | 3028 fps | 96.8% |
| IMR 7828 SSC | <<locked>> | 80% | 39,581 psi | 62% | 3005 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 92% | 38,348 psi | 60% | 2995 fps | 95.7% |
| Lovex S070 | <<locked>> | 80% | 53,243 psi | 83% | 3192 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,723 psi | 56% | 2818 fps | 98.2% |
| Norma 204 | <<locked>> | 80% | 52,069 psi | 82% | 3209 fps | 99.4% |
| Norma 217 | <<locked>> | 88% | 33,547 psi | 53% | 2884 fps | 96.1% |
| Norma MRP | <<locked>> | 80% | 44,106 psi | 69% | 3117 fps | 99.2% |
| Norma URP | <<locked>> | 80% | 53,084 psi | 83% | 3212 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,465 psi | 62% | 3012 fps | 96.2% |
| Ramshot Hunter | <<locked>> | 80% | 52,112 psi | 82% | 3212 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,462 psi | 56% | 2874 fps | 96.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,819 psi | 45% | 1965 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,519 psi | 84% | 3281 fps | 100% |
| ReloadSwiss RS 76 | 96.3 gr | 80% | 33,257 psi | 52% | 2894 fps | 96.7% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 41,176 psi | 65% | 3068 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 46,398 psi | 73% | 3074 fps | 97.8% |
| Rottweil R 905 | <<locked>> | 80% | 45,020 psi | 71% | 3084 fps | 98.5% |
| Shooters World SW4350 | <<locked>> | 80% | 53,243 psi | 83% | 3192 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,722 psi | 84% | 3143 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,686 psi | 70% | 3077 fps | 98.4% |
| Somchem S361 | <<locked>> | 80% | 47,442 psi | 74% | 3061 fps | 97.4% |
| Somchem S365 | <<locked>> | 80% | 50,778 psi | 80% | 3159 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,455 psi | 71% | 3058 fps | 99.1% |
| Vihtavuori N165 | <<locked>> | 80% | 39,697 psi | 62% | 2917 fps | 97.7% |
| Vihtavuori N550 | <<locked>> | 80% | 53,853 psi | 84% | 3205 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,701 psi | 70% | 3068 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,859 psi | 69% | 3107 fps | 96.5% |
| Vihtavuori N565 | <<locked>> | 82% | 38,943 psi | 61% | 2966 fps | 95.2% |
| Vihtavuori N568 | <<locked>> | 90% | 45,498 psi | 71% | 3159 fps | 96.1% |
| Vihtavuori N570 | 109.7 gr | 94% | 49,879 psi | 78% | 3291 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 38,014 psi | 60% | 3031 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,872 psi | 66% | 2976 fps | 97.7% |
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 61 powders for .30-378 Weath. Mag. loaded with the .308 | 155gr | Frontier RSBT. Hodgdon Retumbo delivers the highest muzzle velocity at 3,435 fps; across all powders the maximum-charge window runs from 2,142 fps to 3,435 fps. ADI AR 2218 gives the best case fill at 100 %, and 61 of the 61 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 155.0 gr projectile in 0.308" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, 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, Vihtavuori N570, ReloadSwiss RS 76 rank at the top here: for .30-378 Weath. Mag. with the .308 | 155gr | Frontier RSBT 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.