Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 166gr | Peregrine Glider GRM bullet and 59 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% | 54,636 psi | 86% | 3120 fps | 100% |
| Accurate High Country | <<locked>> | 86% | 56,710 psi | 89% | 3291 fps | 99.7% |
| Accurate MAGPRO | <<locked>> | 86% | 53,838 psi | 84% | 3228 fps | 98.7% |
| ADI AR 2209 | <<locked>> | 86% | 56,304 psi | 88% | 3222 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 88% | 54,752 psi | 86% | 3235 fps | 99.5% |
| ADI AR 2217 | <<locked>> | 98% | 57,246 psi | 90% | 3268 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 53,650 psi | 84% | 3307 fps | 97.5% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 55,912 psi | 88% | 3287 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 56,434 psi | 88% | 3212 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 55,811 psi | 87% | 3209 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 88% | 55,100 psi | 86% | 3225 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 90% | 56,826 psi | 89% | 3186 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 57,072 psi | 89% | 3264 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 57,609 psi | 90% | 3281 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 55,216 psi | 87% | 3291 fps | 97.7% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 55,622 psi | 87% | 3189 fps | 97.8% |
| Bofors RP15 | <<locked>> | 90% | 54,317 psi | 85% | 3212 fps | 99.9% |
| Bofors RP30 | <<locked>> | 96% | 56,869 psi | 89% | 3278 fps | 99.9% |
| Bofors RP5 | <<locked>> | 88% | 55,100 psi | 86% | 3225 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 94% | 54,795 psi | 86% | 3225 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 88% | 57,740 psi | 90% | 3225 fps | 99.5% |
| Hodgdon H4831 SC | <<locked>> | 88% | 56,681 psi | 89% | 3209 fps | 99.3% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 56,434 psi | 88% | 3120 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 56,275 psi | 88% | 3356 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,521 psi | 59% | 2070 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 54,868 psi | 86% | 3133 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 55,317 psi | 87% | 3136 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 54,404 psi | 85% | 3143 fps | 99.2% |
| IMR 7828 SSC | <<locked>> | 90% | 56,840 psi | 89% | 3278 fps | 99.7% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 50,952 psi | 80% | 3189 fps | 99.4% |
| Lovex S070 | <<locked>> | 82% | 56,913 psi | 89% | 3166 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,347 psi | 88% | 3146 fps | 100% |
| Norma 204 | <<locked>> | 82% | 56,231 psi | 88% | 3199 fps | 99.9% |
| Norma 217ᴾ | <<locked>> | 100% | 51,895 psi | 81% | 3215 fps | 100% |
| Norma MRP | <<locked>> | 86% | 55,042 psi | 86% | 3241 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,956 psi | 89% | 3186 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 54,056 psi | 85% | 3232 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 82% | 56,188 psi | 88% | 3196 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 56,681 psi | 89% | 3222 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,406 psi | 60% | 2116 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 57,232 psi | 90% | 3343 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 56,507 psi | 89% | 3301 fps | 99.3% |
| Rottweil R 904 | <<locked>> | 86% | 56,884 psi | 89% | 3189 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 86% | 55,492 psi | 87% | 3196 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 82% | 56,913 psi | 89% | 3166 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,479 psi | 90% | 3117 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 55,114 psi | 86% | 3196 fps | 99.9% |
| Somchem S361 | <<locked>> | 84% | 54,563 psi | 86% | 3114 fps | 99.1% |
| Somchem S365 | <<locked>> | 82% | 54,607 psi | 86% | 3130 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,738 psi | 87% | 3163 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 55,825 psi | 87% | 3146 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 54,955 psi | 86% | 3163 fps | 96% |
| Vihtavuori N555 | <<locked>> | 86% | 54,824 psi | 86% | 3163 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 54,549 psi | 85% | 3241 fps | 99.2% |
| Vihtavuori N565 | <<locked>> | 92% | 55,259 psi | 87% | 3228 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 96% | 56,971 psi | 89% | 3301 fps | 99% |
| Vihtavuori N570 | <<locked>> | 96% | 54,215 psi | 85% | 3294 fps | 97% |
| Winchester StaBALL HD | <<locked>> | 90% | 56,753 psi | 89% | 3278 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 55,767 psi | 87% | 3159 fps | 99.9% |
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 41,350 psi | 65% | 2877 fps | 99.6% |
| Accurate High Country | <<locked>> | 80% | 45,629 psi | 72% | 3077 fps | 98.1% |
| Accurate MAGPRO | <<locked>> | 80% | 43,236 psi | 68% | 3012 fps | 96.4% |
| ADI AR 2209 | <<locked>> | 80% | 45,730 psi | 72% | 3025 fps | 98.9% |
| ADI AR 2213 | <<locked>> | 80% | 41,060 psi | 64% | 2956 fps | 96.9% |
| ADI AR 2217 | <<locked>> | 86% | 37,420 psi | 59% | 2861 fps | 96.1% |
| ADI AR 2218 | <<locked>> | 96% | 46,238 psi | 72% | 3146 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 82% | 29,646 psi | 46% | 2680 fps | 95.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,663 psi | 83% | 3150 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,672 psi | 72% | 3018 fps | 98.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,698 psi | 65% | 2963 fps | 98.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,321 psi | 63% | 2900 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,722 psi | 54% | 2822 fps | 99.1% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,701 psi | 72% | 3077 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 47,195 psi | 74% | 3133 fps | 95.6% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 45,614 psi | 71% | 2992 fps | 95.4% |
| Bofors RP15 | <<locked>> | 80% | 38,725 psi | 61% | 2887 fps | 97.2% |
| Bofors RP30 | <<locked>> | 82% | 34,621 psi | 54% | 2805 fps | 95% |
| Bofors RP5 | <<locked>> | 80% | 41,698 psi | 65% | 2963 fps | 98.2% |
| Hodgdon H1000 | <<locked>> | 82% | 35,476 psi | 56% | 2812 fps | 95.9% |
| Hodgdon H4831 | <<locked>> | 80% | 43,700 psi | 68% | 2963 fps | 97% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,902 psi | 67% | 2943 fps | 96.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,472 psi | 78% | 3015 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 80% | 33,939 psi | 53% | 2854 fps | 96.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,094 psi | 44% | 1854 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,416 psi | 81% | 3074 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 51,909 psi | 81% | 3081 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,715 psi | 70% | 2953 fps | 97.4% |
| IMR 7828 SSC | <<locked>> | 80% | 39,697 psi | 62% | 2933 fps | 96.5% |
| IMR 8133 Enduron | <<locked>> | 90% | 35,795 psi | 56% | 2854 fps | 95.4% |
| Lovex S070 | <<locked>> | 80% | 53,447 psi | 84% | 3110 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,505 psi | 56% | 2740 fps | 98.6% |
| Norma 204 | <<locked>> | 80% | 52,402 psi | 82% | 3133 fps | 99.7% |
| Norma 217 | <<locked>> | 86% | 31,183 psi | 49% | 2743 fps | 95.7% |
| Norma MRP | <<locked>> | 80% | 44,179 psi | 69% | 3038 fps | 99.5% |
| Norma URP | <<locked>> | 80% | 53,388 psi | 84% | 3127 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,697 psi | 62% | 2943 fps | 96.9% |
| Ramshot Hunter | <<locked>> | 80% | 52,417 psi | 82% | 3130 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,534 psi | 56% | 2805 fps | 97.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,834 psi | 45% | 1900 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 33,170 psi | 52% | 2822 fps | 97.4% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 41,278 psi | 65% | 2995 fps | 95.9% |
| Rottweil R 904 | <<locked>> | 80% | 46,673 psi | 73% | 3002 fps | 98.3% |
| Rottweil R 905 | <<locked>> | 80% | 45,252 psi | 71% | 3005 fps | 98.9% |
| Shooters World SW4350 | <<locked>> | 80% | 53,447 psi | 84% | 3110 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,766 psi | 84% | 3058 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,918 psi | 70% | 3002 fps | 98.9% |
| Somchem S361 | <<locked>> | 80% | 47,688 psi | 75% | 2986 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 50,952 psi | 80% | 3071 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,600 psi | 71% | 2979 fps | 99.4% |
| Vihtavuori N165 | <<locked>> | 80% | 39,711 psi | 62% | 2841 fps | 98.2% |
| Vihtavuori N170 | <<locked>> | 92% | 51,242 psi | 80% | 3094 fps | 95% |
| Vihtavuori N555 | <<locked>> | 80% | 44,744 psi | 70% | 2986 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,961 psi | 69% | 3028 fps | 97.2% |
| Vihtavuori N565 | <<locked>> | 82% | 38,943 psi | 61% | 2890 fps | 95.9% |
| Vihtavuori N568 | <<locked>> | 88% | 42,380 psi | 66% | 3015 fps | 95.7% |
| Vihtavuori N570 | <<locked>> | 92% | 46,688 psi | 73% | 3146 fps | 95% |
| Winchester StaBALL HD | <<locked>> | 80% | 38,261 psi | 60% | 2953 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,959 psi | 66% | 2900 fps | 98.2% |
ᴾ possible press load - work up slowly to this load while watching for signs of excessive pressure.
This overview compares 66 powders for .30-378 Weath. Mag. loaded with the .308 | 166gr | Peregrine Glider GRM. Hodgdon Retumbo delivers the highest muzzle velocity at 3,356 fps; across all powders the maximum-charge window runs from 2,070 fps to 3,356 fps. Accurate 8700 gives the best case fill at 100 %, and 66 of the 66 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 166.0 gr projectile in 0.308" calls for a 1:10.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2218, ADI AR 2225 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, Accurate 8700, IMR 7977 Enduron, Lovex D100 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.