Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 205gr | Sierra GameKing bullet and 42 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Vihtavuori N570 and Alliant Reloder-50.
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>> | 82% | 54,723 psi | 86% | 2844 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,708 psi | 86% | 2966 fps | 98.9% |
| ADI AR 2213 | <<locked>> | 82% | 54,389 psi | 85% | 2949 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 54,215 psi | 85% | 2943 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 54,650 psi | 86% | 3077 fps | 99.5% |
| ADI AR 2225 | <<locked>> | 92% | 54,230 psi | 85% | 2969 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 55,027 psi | 86% | 2946 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 57,174 psi | 90% | 2897 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 54,505 psi | 85% | 2930 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,782 psi | 89% | 3051 fps | 99.5% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,116 psi | 90% | 3048 fps | 99.3% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 54,476 psi | 85% | 2917 fps | 99.3% |
| Bofors RP15 | <<locked>> | 84% | 54,607 psi | 86% | 2936 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 54,317 psi | 85% | 2956 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 55,027 psi | 86% | 2946 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 55,419 psi | 87% | 2956 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 56,608 psi | 89% | 2940 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 55,579 psi | 87% | 2923 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 54,288 psi | 85% | 3025 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,130 psi | 60% | 1893 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 56,536 psi | 89% | 2913 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 57,043 psi | 89% | 2999 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 55,187 psi | 86% | 2874 fps | 96.9% |
| IMR 8133 Enduron | <<locked>> | 96% | 56,826 psi | 89% | 3012 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 56,507 psi | 89% | 2927 fps | 96.3% |
| Lovex S071 | <<locked>> | 88% | 57,029 psi | 89% | 2877 fps | 100% |
| Norma 217 | <<locked>> | 94% | 54,723 psi | 86% | 2976 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 54,534 psi | 85% | 2959 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 56,971 psi | 89% | 2946 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,305 psi | 62% | 1939 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 54,752 psi | 86% | 3005 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 53,896 psi | 84% | 2982 fps | 99.9% |
| Shooters World 50 BMG | <<locked>> | 92% | 56,507 psi | 89% | 2927 fps | 96.3% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,376 psi | 88% | 2969 fps | 98.9% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 49,690 psi | 78% | 2877 fps | 96.2% |
| Vihtavuori N165 | <<locked>> | 84% | 55,317 psi | 87% | 2871 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 54,795 psi | 86% | 2910 fps | 98.2% |
| Vihtavuori N565 | <<locked>> | 86% | 56,057 psi | 88% | 2969 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 54,230 psi | 85% | 2986 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 90% | 55,840 psi | 88% | 3058 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 82% | 54,781 psi | 86% | 2943 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 54,882 psi | 86% | 2877 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% | 51,271 psi | 80% | 2792 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 40,814 psi | 64% | 2707 fps | 95.7% |
| ADI AR 2213 | <<locked>> | 80% | 50,691 psi | 79% | 2890 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 38,174 psi | 60% | 2644 fps | 98.7% |
| ADI AR 2218 | 100.2 gr | 84% | 37,826 psi | 59% | 2717 fps | 95% |
| ADI AR 2225 | <<locked>> | 80% | 35,563 psi | 56% | 2621 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,430 psi | 81% | 2887 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 50,198 psi | 79% | 2799 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 44,411 psi | 70% | 2766 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 39,233 psi | 61% | 2710 fps | 95.6% |
| Alliant Reloder-50 | 104.1 gr | 86% | 39,566 psi | 62% | 2710 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,732 psi | 75% | 2795 fps | 98.3% |
| Bofors RP15 | <<locked>> | 80% | 47,964 psi | 75% | 2825 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 41,524 psi | 65% | 2720 fps | 99.3% |
| Bofors RP5 | <<locked>> | 80% | 51,430 psi | 81% | 2887 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,539 psi | 65% | 2717 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 80% | 52,895 psi | 83% | 2877 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,938 psi | 81% | 2864 fps | 99.9% |
| Hodgdon Retumbo | <<locked>> | 80% | 43,772 psi | 69% | 2841 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,732 psi | 45% | 1693 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 53,113 psi | 83% | 2858 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 49,719 psi | 78% | 2877 fps | 99.9% |
| IMR 7977 Enduron | <<locked>> | 84% | 48,588 psi | 76% | 2756 fps | 95.4% |
| IMR 8133 Enduron | <<locked>> | 80% | 33,098 psi | 52% | 2539 fps | 96.8% |
| Lovex D100 | <<locked>> | 90% | 52,678 psi | 83% | 2864 fps | 95.3% |
| Lovex S071 | <<locked>> | 80% | 44,295 psi | 69% | 2674 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,721 psi | 53% | 2569 fps | 98.9% |
| Ramshot Grand | <<locked>> | 80% | 50,691 psi | 79% | 2897 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 45,672 psi | 72% | 2766 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,602 psi | 46% | 1736 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,526 psi | 68% | 2818 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 40,001 psi | 63% | 2717 fps | 97.9% |
| Shooters World 50 BMG | <<locked>> | 90% | 52,678 psi | 83% | 2864 fps | 95.3% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,859 psi | 67% | 2726 fps | 95.9% |
| Vihtavuori 20N29 | <<locked>> | 98% | 46,311 psi | 73% | 2812 fps | 95.2% |
| Vihtavuori N165 | <<locked>> | 80% | 48,646 psi | 76% | 2766 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 41,930 psi | 66% | 2667 fps | 95% |
| Vihtavuori N565 | <<locked>> | 80% | 45,818 psi | 72% | 2792 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 80% | 40,828 psi | 64% | 2730 fps | 97.6% |
| Vihtavuori N570 | 93.5 gr | 80% | 39,073 psi | 61% | 2720 fps | 95% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,908 psi | 80% | 2884 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 51,242 psi | 80% | 2818 fps | 100% |
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 42 powders for .30-378 Weath. Mag. loaded with the .308 | 205gr | Sierra GameKing. ADI AR 2218 delivers the highest muzzle velocity at 3,077 fps; across all powders the maximum-charge window runs from 1,893 fps to 3,077 fps. Accurate 8700 gives the best case fill at 100 %, and 42 of the 42 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 60–90 %, leaving at least 10 % headroom. The 205.0 gr projectile in 0.308" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, Hodgdon TrailBoss, ReloadSwiss RS 14 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. ADI AR 2218, Vihtavuori N570, Alliant Reloder-50 rank at the top here: for .30-378 Weath. Mag. with the .308 | 205gr | Sierra 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.