Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 155gr | Merlin Virtus bullet and 61 powders. The key underlying parameters are shown in the table above.
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% | 54,027 psi | 85% | 3199 fps | 100% |
| Accurate High Country | <<locked>> | 86% | 55,927 psi | 88% | 3366 fps | 99.4% |
| Accurate MAGPRO | <<locked>> | 88% | 56,971 psi | 89% | 3369 fps | 98.9% |
| ADI AR 2209 | <<locked>> | 86% | 55,666 psi | 87% | 3301 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 88% | 53,867 psi | 84% | 3304 fps | 99.1% |
| ADI AR 2217 | <<locked>> | 98% | 56,521 psi | 89% | 3340 fps | 99.7% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 53,156 psi | 83% | 3373 fps | 96.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 55,143 psi | 86% | 3360 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 55,593 psi | 87% | 3291 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 55,201 psi | 87% | 3287 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 88% | 54,244 psi | 85% | 3297 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 90% | 55,999 psi | 88% | 3268 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 56,405 psi | 88% | 3340 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 56,826 psi | 89% | 3360 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 54,462 psi | 85% | 3356 fps | 97% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 55,027 psi | 86% | 3261 fps | 97.3% |
| Bofors RP15 | <<locked>> | 92% | 57,435 psi | 90% | 3353 fps | 99.9% |
| Bofors RP30 | <<locked>> | 96% | 56,028 psi | 88% | 3350 fps | 99.7% |
| Bofors RP5 | <<locked>> | 88% | 54,244 psi | 85% | 3297 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 94% | 54,056 psi | 85% | 3297 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 88% | 57,058 psi | 89% | 3301 fps | 99.1% |
| Hodgdon H4831 SC | <<locked>> | 88% | 55,869 psi | 88% | 3281 fps | 99% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 55,724 psi | 87% | 3205 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 55,245 psi | 87% | 3428 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,391 psi | 59% | 2146 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 54,230 psi | 85% | 3215 fps | 99.9% |
| IMR 4831 | <<locked>> | 82% | 54,621 psi | 86% | 3215 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 57,406 psi | 90% | 3278 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 90% | 56,173 psi | 88% | 3353 fps | 99.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 50,212 psi | 79% | 3255 fps | 98.9% |
| Lovex S070 | <<locked>> | 82% | 56,246 psi | 88% | 3245 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 55,695 psi | 87% | 3225 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,550 psi | 87% | 3274 fps | 99.7% |
| Norma 217ᴾ | <<locked>> | 100% | 51,039 psi | 80% | 3284 fps | 100% |
| Norma MRP | <<locked>> | 86% | 54,273 psi | 85% | 3317 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,260 psi | 88% | 3264 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 57,479 psi | 90% | 3379 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 82% | 55,448 psi | 87% | 3274 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 55,941 psi | 88% | 3294 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,363 psi | 60% | 2195 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 57,348 psi | 90% | 3343 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 56,521 psi | 89% | 3419 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 55,883 psi | 88% | 3369 fps | 98.9% |
| Rottweil R 904 | <<locked>> | 86% | 56,217 psi | 88% | 3264 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 86% | 54,708 psi | 86% | 3271 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 82% | 56,246 psi | 88% | 3245 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 56,811 psi | 89% | 3196 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 54,317 psi | 85% | 3271 fps | 99.7% |
| Somchem S361 | <<locked>> | 84% | 53,983 psi | 85% | 3186 fps | 98.7% |
| Somchem S365 | <<locked>> | 82% | 53,838 psi | 84% | 3209 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,056 psi | 86% | 3238 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 55,114 psi | 86% | 3225 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 82% | 57,217 psi | 90% | 3261 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 57,725 psi | 90% | 3297 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 53,853 psi | 84% | 3314 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 92% | 54,578 psi | 86% | 3301 fps | 99.1% |
| Vihtavuori N568 | <<locked>> | 96% | 56,362 psi | 88% | 3373 fps | 98.6% |
| Vihtavuori N570 | <<locked>> | 98% | 57,508 psi | 90% | 3438 fps | 97.3% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 57,653 psi | 90% | 3199 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 55,753 psi | 87% | 3356 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 55,071 psi | 86% | 3235 fps | 99.8% |
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 40,785 psi | 64% | 2943 fps | 99.3% |
| Accurate High Country | <<locked>> | 80% | 44,991 psi | 71% | 3143 fps | 97.5% |
| Accurate MAGPRO | <<locked>> | 80% | 42,554 psi | 67% | 3074 fps | 95.5% |
| ADI AR 2209 | <<locked>> | 80% | 45,208 psi | 71% | 3097 fps | 98.4% |
| ADI AR 2213 | <<locked>> | 80% | 40,480 psi | 63% | 3022 fps | 96% |
| ADI AR 2217 | <<locked>> | 86% | 36,854 psi | 58% | 2920 fps | 95.1% |
| ADI AR 2218 | <<locked>> | 98% | 49,124 psi | 77% | 3287 fps | 95.4% |
| ADI AR 2225 | <<locked>> | 84% | 31,270 psi | 49% | 2799 fps | 95.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 51,982 psi | 81% | 3232 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,136 psi | 71% | 3087 fps | 98.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,060 psi | 64% | 3025 fps | 97.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 39,697 psi | 62% | 2969 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,214 psi | 54% | 2881 fps | 98.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,020 psi | 71% | 3146 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 50,430 psi | 79% | 3274 fps | 96% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 48,211 psi | 76% | 3127 fps | 95.6% |
| Bofors RP15 | <<locked>> | 80% | 38,087 psi | 60% | 2949 fps | 96.4% |
| Bofors RP30 | <<locked>> | 84% | 36,593 psi | 57% | 2930 fps | 95.1% |
| Bofors RP5 | <<locked>> | 80% | 41,060 psi | 64% | 3025 fps | 97.5% |
| Hodgdon H1000 | <<locked>> | 84% | 37,521 psi | 59% | 2940 fps | 96.1% |
| Hodgdon H4831 | <<locked>> | 80% | 43,105 psi | 68% | 3025 fps | 96.2% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,322 psi | 66% | 3009 fps | 96% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,718 psi | 76% | 3091 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 33,388 psi | 52% | 2907 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,036 psi | 44% | 1926 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,894 psi | 80% | 3153 fps | 99.8% |
| IMR 4831 | <<locked>> | 80% | 51,169 psi | 80% | 3159 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,266 psi | 69% | 3025 fps | 96.8% |
| IMR 7828 SSC | <<locked>> | 80% | 39,131 psi | 61% | 2995 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 92% | 37,710 psi | 59% | 2976 fps | 95.5% |
| Lovex S070 | <<locked>> | 80% | 52,794 psi | 83% | 3186 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 34,838 psi | 55% | 2799 fps | 97.9% |
| Norma 204 | <<locked>> | 80% | 51,692 psi | 81% | 3205 fps | 99.3% |
| Norma 217 | <<locked>> | 88% | 32,895 psi | 52% | 2861 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 43,540 psi | 68% | 3104 fps | 99.1% |
| Norma URP | <<locked>> | 80% | 52,707 psi | 83% | 3209 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 38,943 psi | 61% | 2999 fps | 96% |
| Ramshot Hunter | <<locked>> | 80% | 51,706 psi | 81% | 3205 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 34,925 psi | 55% | 2858 fps | 96.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,732 psi | 45% | 1969 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,287 psi | 84% | 3274 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 32,648 psi | 51% | 2874 fps | 96.3% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 40,596 psi | 64% | 3051 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 46,079 psi | 72% | 3071 fps | 97.7% |
| Rottweil R 905 | <<locked>> | 80% | 44,556 psi | 70% | 3074 fps | 98.4% |
| Shooters World SW4350 | <<locked>> | 80% | 52,794 psi | 83% | 3186 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,243 psi | 83% | 3136 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,222 psi | 69% | 3068 fps | 98.3% |
| Somchem S361 | <<locked>> | 80% | 47,079 psi | 74% | 3054 fps | 97.4% |
| Somchem S365 | <<locked>> | 80% | 50,314 psi | 79% | 3153 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,020 psi | 71% | 3048 fps | 99.1% |
| Vihtavuori N165 | <<locked>> | 80% | 39,189 psi | 61% | 2907 fps | 97.6% |
| Vihtavuori N550 | <<locked>> | 80% | 53,388 psi | 84% | 3199 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,063 psi | 69% | 3058 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,352 psi | 68% | 3094 fps | 96.4% |
| Vihtavuori N565 | <<locked>> | 84% | 41,162 psi | 65% | 3022 fps | 96% |
| Vihtavuori N568 | <<locked>> | 90% | 45,020 psi | 71% | 3150 fps | 95.9% |
| Vihtavuori N570 | <<locked>> | 94% | 49,545 psi | 78% | 3284 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,780 psi | 84% | 3140 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,405 psi | 59% | 3012 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,350 psi | 65% | 2966 fps | 97.6% |
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 | Merlin Virtus. Vihtavuori N570 delivers the highest muzzle velocity at 3,438 fps; across all powders the maximum-charge window runs from 2,146 fps to 3,438 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 1:12.5 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. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.