Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 220gr | Woodleigh RN SN bullet and 36 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Alliant Reloder-50 and Alliant Reloder-33.
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 8700 | <<locked>> | 98% | 54,810 psi | 86% | 2881 fps | 99.4% |
| ADI AR 2213 | <<locked>> | 82% | 57,595 psi | 90% | 2907 fps | 100% |
| ADI AR 2217 | <<locked>> | 88% | 53,998 psi | 85% | 2848 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 54,563 psi | 86% | 2989 fps | 99.8% |
| ADI AR 2225 | <<locked>> | 90% | 54,186 psi | 85% | 2871 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 56,695 psi | 89% | 2795 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 84% | 54,157 psi | 85% | 2828 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 56,753 psi | 89% | 2959 fps | 99.8% |
| Alliant Reloder-50 | <<locked>> | 94% | 57,261 psi | 90% | 2966 fps | 99.6% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 57,246 psi | 90% | 2874 fps | 99.8% |
| Bofors RP15 | <<locked>> | 82% | 54,186 psi | 85% | 2838 fps | 100% |
| Bofors RP30 | <<locked>> | 86% | 54,157 psi | 85% | 2861 fps | 100% |
| Hodgdon H1000 | <<locked>> | 86% | 55,013 psi | 86% | 2858 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 84% | 54,244 psi | 85% | 2927 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,348 psi | 60% | 1837 fps | 100% |
| Hodgdon US 869 | <<locked>> | 96% | 55,274 psi | 87% | 2881 fps | 96.4% |
| IMR 7828 SSC | <<locked>> | 82% | 56,449 psi | 88% | 2894 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 86% | 54,346 psi | 85% | 2779 fps | 97.5% |
| IMR 8133 Enduron | <<locked>> | 94% | 56,971 psi | 89% | 2920 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 55,927 psi | 88% | 2838 fps | 97% |
| Lovex S071 | <<locked>> | 86% | 56,463 psi | 88% | 2776 fps | 100% |
| Norma 217 | <<locked>> | 92% | 54,897 psi | 86% | 2884 fps | 100% |
| Ramshot LRT | <<locked>> | 92% | 53,969 psi | 85% | 2913 fps | 96.2% |
| Ramshot Magnum | <<locked>> | 84% | 56,521 psi | 89% | 2844 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,421 psi | 62% | 1880 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 54,679 psi | 86% | 2907 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 57,740 psi | 90% | 2953 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 55,927 psi | 88% | 2838 fps | 97% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 56,304 psi | 88% | 2884 fps | 99.3% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 53,505 psi | 84% | 2861 fps | 97.9% |
| Vihtavuori 24N41 | <<locked>> | 94% | 55,753 psi | 87% | 2887 fps | 96.4% |
| Vihtavuori N165 | <<locked>> | 82% | 54,708 psi | 86% | 2772 fps | 100% |
| Vihtavuori N170 | <<locked>> | 86% | 54,230 psi | 85% | 2818 fps | 98.7% |
| Vihtavuori N565 | <<locked>> | 84% | 55,680 psi | 87% | 2871 fps | 100% |
| Vihtavuori N568 | <<locked>> | 86% | 54,085 psi | 85% | 2890 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 55,767 psi | 87% | 2966 fps | 99.6% |
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 8700 | <<locked>> | 88% | 38,000 psi | 60% | 2566 fps | 95.5% |
| ADI AR 2213 | <<locked>> | 80% | 53,737 psi | 84% | 2848 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 40,814 psi | 64% | 2618 fps | 99.6% |
| ADI AR 2218 | 98.2 gr | 82% | 37,666 psi | 59% | 2635 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 38,130 psi | 60% | 2595 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 53,185 psi | 83% | 2746 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 47,297 psi | 74% | 2723 fps | 100% |
| Alliant Reloder-33 | 97.6 gr | 80% | 39,291 psi | 62% | 2628 fps | 96.5% |
| Alliant Reloder-50 | 102.1 gr | 84% | 39,769 psi | 62% | 2635 fps | 96% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 50,212 psi | 79% | 2759 fps | 99.2% |
| Bofors RP15 | <<locked>> | 80% | 50,821 psi | 80% | 2785 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 44,222 psi | 69% | 2690 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 80% | 44,469 psi | 70% | 2687 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 47,050 psi | 74% | 2808 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,848 psi | 45% | 1640 fps | 100% |
| Hodgdon US 869 | <<locked>> | 94% | 51,547 psi | 81% | 2818 fps | 95.5% |
| IMR 7828 SSC | <<locked>> | 80% | 52,649 psi | 83% | 2835 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 80% | 44,918 psi | 70% | 2608 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 80% | 35,636 psi | 56% | 2523 fps | 98.4% |
| Lovex D100 | <<locked>> | 86% | 48,530 psi | 76% | 2713 fps | 95.2% |
| Lovex S071 | <<locked>> | 80% | 46,775 psi | 73% | 2631 fps | 100% |
| Norma 217 | <<locked>> | 80% | 36,492 psi | 57% | 2549 fps | 99.8% |
| Ramshot LRT | <<locked>> | 90% | 50,415 psi | 79% | 2851 fps | 95.3% |
| Ramshot Magnum | <<locked>> | 80% | 48,776 psi | 76% | 2730 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,733 psi | 47% | 1680 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 47,036 psi | 74% | 2789 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 43,062 psi | 67% | 2697 fps | 99.1% |
| Shooters World 50 BMG | <<locked>> | 86% | 48,530 psi | 76% | 2713 fps | 95.2% |
| SNPE Vectan SP 13 | <<locked>> | 88% | 40,147 psi | 63% | 2589 fps | 95.9% |
| Vihtavuori 20N29 | <<locked>> | 94% | 43,337 psi | 68% | 2674 fps | 95.2% |
| Vihtavuori 24N41 | <<locked>> | 92% | 51,909 psi | 81% | 2822 fps | 95.5% |
| Vihtavuori N165 | <<locked>> | 80% | 51,184 psi | 80% | 2717 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 44,295 psi | 69% | 2638 fps | 96.6% |
| Vihtavuori N565 | <<locked>> | 80% | 48,733 psi | 76% | 2756 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 80% | 43,758 psi | 69% | 2707 fps | 98.9% |
| Vihtavuori N570 | <<locked>> | 80% | 41,930 psi | 66% | 2700 fps | 96.9% |
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 37 powders for .30-378 Weath. Mag. loaded with the .308 | 220gr | Woodleigh RN SN. ADI AR 2218 delivers the highest muzzle velocity at 2,989 fps; across all powders the maximum-charge window runs from 1,837 fps to 2,989 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 37 of the 37 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 220.0 gr projectile in 0.308" calls for a 1:14.5 twist; slower twists will usually not stabilise this weight. Hodgdon TrailBoss, ReloadSwiss RS 14, Vihtavuori 20N29 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, Alliant Reloder-50, Alliant Reloder-33 rank at the top here: for .30-378 Weath. Mag. with the .308 | 220gr | Woodleigh RN SN they combine a high case fill with complete burn and sit in the upper velocity band. 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.