Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 200gr | Speer Grand Slam bullet and 42 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>> | 82% | 54,520 psi | 85% | 2871 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 54,607 psi | 86% | 2992 fps | 98.8% |
| Accurate MAGPRO | <<locked>> | 82% | 57,580 psi | 90% | 3048 fps | 100% |
| ADI AR 2213 | <<locked>> | 82% | 54,143 psi | 85% | 2979 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 54,027 psi | 85% | 2972 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 54,433 psi | 85% | 3104 fps | 99.4% |
| ADI AR 2225 | <<locked>> | 92% | 53,896 psi | 84% | 2995 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 54,810 psi | 86% | 2972 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 56,956 psi | 89% | 2927 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 54,230 psi | 85% | 2956 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 56,623 psi | 89% | 3077 fps | 99.4% |
| Alliant Reloder-50 | <<locked>> | 96% | 57,000 psi | 89% | 3077 fps | 99.1% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 54,331 psi | 85% | 2943 fps | 99.2% |
| Bofors RP15 | <<locked>> | 84% | 54,389 psi | 85% | 2966 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 54,114 psi | 85% | 2986 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 54,810 psi | 86% | 2972 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 55,230 psi | 87% | 2986 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 56,376 psi | 88% | 2966 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 82% | 55,405 psi | 87% | 2949 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 54,085 psi | 85% | 3054 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,203 psi | 60% | 1919 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 56,376 psi | 88% | 2940 fps | 100% |
| IMR 7828 SSC | <<locked>> | 84% | 56,782 psi | 89% | 3025 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 55,071 psi | 86% | 2900 fps | 96.7% |
| IMR 8133 Enduron | <<locked>> | 96% | 56,652 psi | 89% | 3038 fps | 100% |
| Lovex D100 | <<locked>> | 92% | 56,391 psi | 88% | 2956 fps | 96% |
| Lovex S071 | <<locked>> | 88% | 56,797 psi | 89% | 2904 fps | 100% |
| Norma 217 | <<locked>> | 94% | 54,534 psi | 85% | 3002 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 54,230 psi | 85% | 2989 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 56,840 psi | 89% | 2976 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,233 psi | 61% | 1965 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 54,592 psi | 86% | 3035 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 53,708 psi | 84% | 3009 fps | 99.9% |
| Shooters World 50 BMG | <<locked>> | 92% | 56,391 psi | 88% | 2956 fps | 96% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,188 psi | 88% | 2995 fps | 98.7% |
| Vihtavuori N165 | <<locked>> | 84% | 55,216 psi | 87% | 2900 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 54,694 psi | 86% | 2940 fps | 98% |
| Vihtavuori N565 | <<locked>> | 86% | 55,898 psi | 88% | 2995 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 54,114 psi | 85% | 3012 fps | 99.7% |
| Vihtavuori N570 | <<locked>> | 90% | 55,651 psi | 87% | 3084 fps | 99% |
| Winchester StaBALL HD | <<locked>> | 82% | 54,491 psi | 85% | 2969 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 54,636 psi | 86% | 2907 fps | 100% |
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 50,981 psi | 80% | 2818 fps | 100% |
| Accurate 8700 | <<locked>> | 92% | 40,640 psi | 64% | 2726 fps | 95.3% |
| Accurate MAGPRO | <<locked>> | 80% | 53,737 psi | 84% | 2986 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 50,517 psi | 79% | 2917 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 80% | 38,043 psi | 60% | 2667 fps | 98.5% |
| ADI AR 2218 | <<locked>> | 86% | 40,466 psi | 63% | 2808 fps | 95.9% |
| ADI AR 2225 | <<locked>> | 80% | 35,302 psi | 55% | 2641 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,271 psi | 80% | 2913 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 50,067 psi | 78% | 2828 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 44,150 psi | 69% | 2789 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 82% | 39,044 psi | 61% | 2730 fps | 95.2% |
| Alliant Reloder-50 | <<locked>> | 88% | 42,496 psi | 67% | 2802 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 47,674 psi | 75% | 2825 fps | 98.1% |
| Bofors RP15 | <<locked>> | 80% | 47,848 psi | 75% | 2854 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 41,249 psi | 65% | 2743 fps | 99.1% |
| Bofors RP5 | <<locked>> | 80% | 51,271 psi | 80% | 2913 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,394 psi | 65% | 2740 fps | 99.5% |
| Hodgdon H4831 | <<locked>> | 80% | 52,721 psi | 83% | 2907 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 51,793 psi | 81% | 2890 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 80% | 43,453 psi | 68% | 2864 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,689 psi | 45% | 1716 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 52,852 psi | 83% | 2884 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 80% | 49,385 psi | 77% | 2904 fps | 99.8% |
| IMR 7977 Enduron | <<locked>> | 84% | 48,385 psi | 76% | 2782 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 80% | 32,982 psi | 52% | 2559 fps | 96.5% |
| Lovex D100 | <<locked>> | 90% | 52,605 psi | 82% | 2890 fps | 95.1% |
| Lovex S071 | <<locked>> | 80% | 44,121 psi | 69% | 2700 fps | 100% |
| Norma 217 | <<locked>> | 80% | 33,576 psi | 53% | 2589 fps | 98.7% |
| Ramshot Grand | <<locked>> | 80% | 50,444 psi | 79% | 2923 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 45,542 psi | 71% | 2792 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,530 psi | 46% | 1759 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,236 psi | 68% | 2838 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 39,726 psi | 62% | 2736 fps | 97.6% |
| Shooters World 50 BMG | <<locked>> | 90% | 52,605 psi | 82% | 2890 fps | 95.1% |
| SNPE Vectan SP 13 | <<locked>> | 92% | 42,714 psi | 67% | 2746 fps | 95.6% |
| Vihtavuori N165 | <<locked>> | 80% | 48,385 psi | 76% | 2789 fps | 100% |
| Vihtavuori N170 | <<locked>> | 82% | 44,715 psi | 70% | 2753 fps | 95.6% |
| Vihtavuori N565 | <<locked>> | 80% | 45,629 psi | 72% | 2815 fps | 99.3% |
| Vihtavuori N568 | <<locked>> | 80% | 40,727 psi | 64% | 2753 fps | 97.4% |
| Vihtavuori N570 | <<locked>> | 82% | 41,858 psi | 66% | 2812 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 50,647 psi | 79% | 2913 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 51,068 psi | 80% | 2848 fps | 100% |
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 47 powders for .30-378 Weath. Mag. loaded with the .308 | 200gr | Speer Grand Slam. ADI AR 2218 delivers the highest muzzle velocity at 3,104 fps; across all powders the maximum-charge window runs from 1,919 fps to 3,104 fps. Accurate 8700 gives the best case fill at 100 %, and 47 of the 47 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 200.0 gr projectile in 0.308" calls for a 1:14.5 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. As outliers, Hodgdon 50BMG 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.