Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 165gr | Sierra SBT GameKing bullet and 51 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N570, Hodgdon Retumbo 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>> | 86% | 54,824 psi | 86% | 3127 fps | 100% |
| Accurate High Country | <<locked>> | 84% | 56,666 psi | 89% | 3294 fps | 99.8% |
| Accurate MAGPRO | <<locked>> | 86% | 57,696 psi | 90% | 3301 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 84% | 55,825 psi | 87% | 3222 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 86% | 54,433 psi | 85% | 3232 fps | 99.6% |
| ADI AR 2217 | <<locked>> | 96% | 57,363 psi | 90% | 3274 fps | 99.9% |
| ADI AR 2218 | <<locked>> | 98% | 53,969 psi | 85% | 3320 fps | 97.8% |
| ADI AR 2225 | <<locked>> | 98% | 56,478 psi | 89% | 3294 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 55,999 psi | 88% | 3215 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 55,419 psi | 87% | 3209 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 86% | 54,969 psi | 86% | 3228 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 56,811 psi | 89% | 3189 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 57,363 psi | 90% | 3268 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 53,621 psi | 84% | 3219 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 55,782 psi | 87% | 3301 fps | 97.9% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 55,651 psi | 87% | 3287 fps | 97.4% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 55,042 psi | 86% | 3186 fps | 97.9% |
| Bofors RP15 | <<locked>> | 88% | 54,404 psi | 85% | 3219 fps | 99.9% |
| Bofors RP30 | <<locked>> | 94% | 57,276 psi | 90% | 3284 fps | 99.9% |
| Bofors RP5 | <<locked>> | 86% | 54,969 psi | 86% | 3228 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 54,810 psi | 86% | 3232 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 86% | 57,145 psi | 90% | 3222 fps | 99.5% |
| Hodgdon H4831 SC | <<locked>> | 86% | 56,173 psi | 88% | 3209 fps | 99.4% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 56,130 psi | 88% | 3123 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 56,695 psi | 89% | 3363 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,753 psi | 59% | 2093 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 57,435 psi | 90% | 3202 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 88% | 56,840 psi | 89% | 3281 fps | 99.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 55,448 psi | 87% | 3271 fps | 99.8% |
| Lovex S071 | <<locked>> | 92% | 56,782 psi | 89% | 3156 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 56,681 psi | 89% | 3294 fps | 100% |
| Norma MRP | <<locked>> | 84% | 55,056 psi | 86% | 3241 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 54,128 psi | 85% | 3238 fps | 99.7% |
| Ramshot Magnum | <<locked>> | 90% | 56,681 psi | 89% | 3222 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,798 psi | 61% | 2142 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 53,548 psi | 84% | 3281 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 57,043 psi | 89% | 3310 fps | 99.5% |
| Rottweil R 904 | <<locked>> | 84% | 56,347 psi | 88% | 3186 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 84% | 55,245 psi | 87% | 3199 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 54,868 psi | 86% | 3196 fps | 99.9% |
| Somchem S361 | <<locked>> | 82% | 54,128 psi | 85% | 3110 fps | 99.1% |
| Somchem S385 | <<locked>> | 84% | 55,666 psi | 87% | 3166 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 55,608 psi | 87% | 3150 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 55,013 psi | 86% | 3169 fps | 96.2% |
| Vihtavuori N555 | <<locked>> | 84% | 55,056 psi | 86% | 3166 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 54,433 psi | 85% | 3245 fps | 99.3% |
| Vihtavuori N565 | <<locked>> | 90% | 55,637 psi | 87% | 3238 fps | 99.6% |
| Vihtavuori N568 | <<locked>> | 94% | 57,508 psi | 90% | 3314 fps | 99.2% |
| Vihtavuori N570 | <<locked>> | 94% | 54,810 psi | 86% | 3307 fps | 97.3% |
| Winchester StaBALL HD | <<locked>> | 88% | 57,464 psi | 90% | 3287 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 55,477 psi | 87% | 3163 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% | 44,817 psi | 70% | 2949 fps | 99.9% |
| Accurate High Country | <<locked>> | 80% | 49,182 psi | 77% | 3153 fps | 98.9% |
| Accurate MAGPRO | <<locked>> | 80% | 46,586 psi | 73% | 3087 fps | 97.4% |
| ADI AR 2209 | <<locked>> | 80% | 48,849 psi | 77% | 3091 fps | 99.4% |
| ADI AR 2213 | <<locked>> | 80% | 44,106 psi | 69% | 3028 fps | 97.9% |
| ADI AR 2217 | <<locked>> | 82% | 35,143 psi | 55% | 2802 fps | 95.2% |
| ADI AR 2218 | <<locked>> | 94% | 46,456 psi | 73% | 3156 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 80% | 30,240 psi | 47% | 2700 fps | 96.2% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 49,182 psi | 77% | 3091 fps | 99.5% |
| Alliant Reloder-19 | <<locked>> | 80% | 48,718 psi | 76% | 3084 fps | 99.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 44,889 psi | 70% | 3035 fps | 99% |
| Alliant Reloder-23 | <<locked>> | 80% | 43,598 psi | 68% | 2966 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 37,840 psi | 59% | 2900 fps | 99.7% |
| Alliant Reloder-26 | <<locked>> | 80% | 49,690 psi | 78% | 3150 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 47,877 psi | 75% | 3150 fps | 96% |
| Alliant Reloder-50 | <<locked>> | 96% | 47,906 psi | 75% | 3136 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 45,281 psi | 71% | 2995 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 41,756 psi | 65% | 2963 fps | 98.2% |
| Bofors RP30 | <<locked>> | 80% | 35,346 psi | 55% | 2822 fps | 95.4% |
| Bofors RP5 | <<locked>> | 80% | 44,889 psi | 70% | 3035 fps | 99% |
| Hodgdon H1000 | <<locked>> | 80% | 35,752 psi | 56% | 2822 fps | 96.2% |
| Hodgdon H4831 | <<locked>> | 80% | 46,514 psi | 73% | 3025 fps | 97.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 45,832 psi | 72% | 3012 fps | 97.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 52,620 psi | 82% | 3068 fps | 100% |
| Hodgdon Retumbo | 92.2 gr | 80% | 36,956 psi | 58% | 2943 fps | 97.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,355 psi | 44% | 1877 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,456 psi | 74% | 3015 fps | 98.2% |
| IMR 7828 SSC | <<locked>> | 80% | 42,873 psi | 67% | 3009 fps | 97.6% |
| IMR 8133 Enduron | <<locked>> | 88% | 36,622 psi | 57% | 2871 fps | 95.8% |
| Lovex S071 | <<locked>> | 80% | 38,566 psi | 60% | 2815 fps | 99.3% |
| Norma 217 | <<locked>> | 82% | 29,936 psi | 47% | 2700 fps | 95% |
| Norma MRP | <<locked>> | 80% | 47,718 psi | 75% | 3110 fps | 99.9% |
| Ramshot Grand | <<locked>> | 80% | 43,004 psi | 67% | 3018 fps | 98% |
| Ramshot Magnum | <<locked>> | 80% | 38,812 psi | 61% | 2884 fps | 98.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,109 psi | 46% | 1923 fps | 100% |
| ReloadSwiss RS 76 | 98.6 gr | 80% | 36,303 psi | 57% | 2910 fps | 98.7% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 38,928 psi | 61% | 2936 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 49,487 psi | 78% | 3064 fps | 98.9% |
| Rottweil R 905 | <<locked>> | 80% | 48,385 psi | 76% | 3074 fps | 99.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 48,051 psi | 75% | 3068 fps | 99.4% |
| Somchem S361 | <<locked>> | 80% | 50,531 psi | 79% | 3048 fps | 98.6% |
| Somchem S385 | <<locked>> | 80% | 48,820 psi | 77% | 3045 fps | 99.8% |
| Vihtavuori N165 | <<locked>> | 80% | 42,699 psi | 67% | 2910 fps | 98.9% |
| Vihtavuori N170 | <<locked>> | 90% | 51,372 psi | 81% | 3100 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 80% | 48,298 psi | 76% | 3054 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 47,297 psi | 74% | 3104 fps | 98.1% |
| Vihtavuori N565 | <<locked>> | 80% | 39,363 psi | 62% | 2904 fps | 96.2% |
| Vihtavuori N568 | <<locked>> | 86% | 42,975 psi | 67% | 3025 fps | 96% |
| Vihtavuori N570 | 107.6 gr | 90% | 47,311 psi | 74% | 3159 fps | 95.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 42,206 psi | 66% | 3028 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 44,933 psi | 70% | 2969 fps | 98.9% |
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 51 powders for .30-378 Weath. Mag. loaded with the .308 | 165gr | Sierra SBT GameKing. Hodgdon Retumbo delivers the highest muzzle velocity at 3,363 fps; across all powders the maximum-charge window runs from 2,093 fps to 3,363 fps. Alliant Reloder-50 gives the best case fill at 100 %, and 51 of the 51 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 1:13.5 twist; slower twists will usually not stabilise this weight. Alliant Reloder-50, Hodgdon TrailBoss, IMR 8133 Enduron 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. Vihtavuori N570, Hodgdon Retumbo, ReloadSwiss RS 76 rank at the top here: for .30-378 Weath. Mag. with the .308 | 165gr | Sierra SBT GameKing 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.