Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 165gr | Geco STAR bullet and 54 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 80 and Vihtavuori N570.
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% | 56,333 psi | 88% | 3153 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 55,651 psi | 87% | 3268 fps | 99.1% |
| ADI AR 2209 | <<locked>> | 84% | 54,012 psi | 85% | 3189 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 88% | 56,478 psi | 89% | 3271 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 96% | 55,274 psi | 87% | 3241 fps | 99.8% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 55,738 psi | 87% | 3356 fps | 98.1% |
| ADI AR 2225 | <<locked>> | 98% | 54,085 psi | 85% | 3261 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 57,334 psi | 90% | 3238 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 56,797 psi | 89% | 3261 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 54,752 psi | 86% | 3163 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 55,129 psi | 86% | 3238 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 55,376 psi | 87% | 3251 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 57,566 psi | 90% | 3337 fps | 98.2% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 52,765 psi | 83% | 3235 fps | 96.7% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 57,145 psi | 90% | 3225 fps | 98.2% |
| Bofors RP15 | <<locked>> | 90% | 55,985 psi | 88% | 3248 fps | 99.9% |
| Bofors RP30 | <<locked>> | 94% | 54,955 psi | 86% | 3248 fps | 99.8% |
| Bofors RP5 | <<locked>> | 88% | 56,797 psi | 89% | 3261 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 56,724 psi | 89% | 3264 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 55,361 psi | 87% | 3196 fps | 99.3% |
| Hodgdon H4831 SC | <<locked>> | 86% | 54,375 psi | 85% | 3179 fps | 99.1% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 54,346 psi | 85% | 3100 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 54,346 psi | 85% | 3330 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,536 psi | 59% | 2087 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 56,304 psi | 88% | 3169 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 56,884 psi | 89% | 3166 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 55,796 psi | 87% | 3176 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 88% | 54,708 psi | 86% | 3245 fps | 99.6% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 52,968 psi | 83% | 3228 fps | 99.6% |
| Lovex S071 | <<locked>> | 92% | 54,331 psi | 85% | 3123 fps | 100% |
| Norma 204 | <<locked>> | 82% | 57,638 psi | 90% | 3228 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 54,012 psi | 85% | 3251 fps | 100% |
| Norma MRP | <<locked>> | 86% | 56,782 psi | 89% | 3278 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 55,898 psi | 88% | 3271 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 82% | 57,595 psi | 90% | 3225 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 54,447 psi | 85% | 3189 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,551 psi | 60% | 2136 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 55,187 psi | 86% | 3310 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 54,476 psi | 85% | 3264 fps | 99.1% |
| Rottweil R 904 | <<locked>> | 84% | 54,592 psi | 86% | 3159 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 86% | 57,130 psi | 90% | 3232 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 56,739 psi | 89% | 3228 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 56,130 psi | 88% | 3150 fps | 99.3% |
| Somchem S365 | <<locked>> | 82% | 56,304 psi | 88% | 3159 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 57,406 psi | 90% | 3196 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 57,377 psi | 90% | 3179 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 56,666 psi | 89% | 3199 fps | 96.5% |
| Vihtavuori N555 | <<locked>> | 86% | 56,376 psi | 88% | 3189 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 56,246 psi | 88% | 3278 fps | 99.5% |
| Vihtavuori N565 | <<locked>> | 92% | 57,145 psi | 90% | 3264 fps | 99.6% |
| Vihtavuori N568 | <<locked>> | 94% | 55,056 psi | 86% | 3271 fps | 98.8% |
| Vihtavuori N570 | <<locked>> | 96% | 56,434 psi | 88% | 3340 fps | 97.6% |
| Winchester StaBALL HD | <<locked>> | 88% | 54,752 psi | 86% | 3251 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 57,508 psi | 90% | 3196 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% | 42,627 psi | 67% | 2907 fps | 99.8% |
| Accurate MAGPRO | <<locked>> | 80% | 44,599 psi | 70% | 3048 fps | 96.8% |
| ADI AR 2209 | <<locked>> | 80% | 47,050 psi | 74% | 3058 fps | 99.2% |
| ADI AR 2213 | <<locked>> | 80% | 42,308 psi | 66% | 2992 fps | 97.3% |
| ADI AR 2217 | <<locked>> | 84% | 35,998 psi | 56% | 2828 fps | 95.5% |
| ADI AR 2218 | <<locked>> | 96% | 47,906 psi | 75% | 3192 fps | 95.9% |
| ADI AR 2225 | <<locked>> | 82% | 30,647 psi | 48% | 2717 fps | 96.3% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,934 psi | 74% | 3051 fps | 99.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,960 psi | 67% | 2995 fps | 98.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 41,713 psi | 65% | 2933 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,940 psi | 56% | 2854 fps | 99.4% |
| Alliant Reloder-26 | <<locked>> | 80% | 47,398 psi | 74% | 3110 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 45,527 psi | 71% | 3100 fps | 95.1% |
| Alliant Reloder-50 | <<locked>> | 98% | 48,718 psi | 76% | 3153 fps | 95.5% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 46,746 psi | 73% | 3028 fps | 95.9% |
| Bofors RP15 | <<locked>> | 80% | 39,842 psi | 62% | 2920 fps | 97.6% |
| Bofors RP30 | <<locked>> | 82% | 35,940 psi | 56% | 2841 fps | 95.6% |
| Bofors RP5 | <<locked>> | 80% | 42,960 psi | 67% | 2995 fps | 98.5% |
| Hodgdon H1000 | <<locked>> | 80% | 34,055 psi | 53% | 2779 fps | 95.3% |
| Hodgdon H4831 | <<locked>> | 80% | 44,904 psi | 70% | 2995 fps | 97.4% |
| Hodgdon H4831 SC | <<locked>> | 80% | 44,077 psi | 69% | 2976 fps | 97.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 50,821 psi | 80% | 3045 fps | 100% |
| Hodgdon Retumbo | 91 gr | 80% | 35,085 psi | 55% | 2890 fps | 97% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,152 psi | 44% | 1870 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 52,692 psi | 83% | 3107 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 53,127 psi | 83% | 3110 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,861 psi | 72% | 2986 fps | 97.8% |
| IMR 7828 SSC | <<locked>> | 80% | 40,988 psi | 64% | 2969 fps | 97% |
| IMR 8133 Enduron | <<locked>> | 90% | 37,173 psi | 58% | 2890 fps | 95.9% |
| Lovex S071 | <<locked>> | 80% | 36,550 psi | 57% | 2769 fps | 98.8% |
| Norma 204 | <<locked>> | 80% | 53,824 psi | 84% | 3166 fps | 99.8% |
| Norma 217 | <<locked>> | 84% | 30,168 psi | 47% | 2710 fps | 95% |
| Norma MRP | <<locked>> | 80% | 45,788 psi | 72% | 3074 fps | 99.7% |
| Ramshot Grand | <<locked>> | 80% | 41,133 psi | 64% | 2982 fps | 97.4% |
| Ramshot Hunter | <<locked>> | 80% | 53,882 psi | 84% | 3163 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 36,854 psi | 58% | 2838 fps | 97.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,877 psi | 45% | 1916 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 34,403 psi | 54% | 2861 fps | 97.9% |
| ReloadSwiss RS 80 | 105.6 gr | 86% | 39,813 psi | 62% | 2959 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 47,790 psi | 75% | 3031 fps | 98.6% |
| Rottweil R 905 | <<locked>> | 80% | 46,456 psi | 73% | 3038 fps | 99.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 46,122 psi | 72% | 3031 fps | 99.1% |
| Somchem S361 | <<locked>> | 80% | 48,849 psi | 77% | 3018 fps | 98.3% |
| Somchem S365 | <<locked>> | 80% | 52,489 psi | 82% | 3100 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,862 psi | 73% | 3012 fps | 99.6% |
| Vihtavuori N165 | <<locked>> | 80% | 40,872 psi | 64% | 2874 fps | 98.5% |
| Vihtavuori N170 | <<locked>> | 92% | 52,794 psi | 83% | 3130 fps | 95.6% |
| Vihtavuori N555 | <<locked>> | 80% | 46,180 psi | 72% | 3015 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 45,498 psi | 71% | 3068 fps | 97.6% |
| Vihtavuori N565 | <<locked>> | 80% | 37,463 psi | 59% | 2858 fps | 95.3% |
| Vihtavuori N568 | <<locked>> | 86% | 40,973 psi | 64% | 2982 fps | 95.2% |
| Vihtavuori N570 | 108.6 gr | 92% | 48,530 psi | 76% | 3189 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 80% | 39,987 psi | 63% | 2986 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 43,250 psi | 68% | 2936 fps | 98.6% |
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 | 165gr | Geco STAR. ADI AR 2218 delivers the highest muzzle velocity at 3,356 fps; across all powders the maximum-charge window runs from 2,087 fps to 3,356 fps. Accurate 8700 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 165.0 gr projectile in 0.308" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2218, Alliant Reloder-50 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 80, Vihtavuori N570 rank at the top here: for .30-378 Weath. Mag. with the .308 | 165gr | Geco STAR they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 8700, IMR 7977 Enduron, Lovex D100 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.