Load Specifications
Load data in caliber .30-378 Weath. Mag. with .308 | 155gr | Norma GTX bullet and 55 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ReloadSwiss RS 76 and ReloadSwiss RS 80.
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% | 56,159 psi | 88% | 3228 fps | 100% |
| Accurate High Country | <<locked>> | 84% | 54,099 psi | 85% | 3327 fps | 99.2% |
| Accurate MAGPRO | <<locked>> | 86% | 55,245 psi | 87% | 3333 fps | 98.6% |
| ADI AR 2209 | <<locked>> | 86% | 57,363 psi | 90% | 3327 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 88% | 55,796 psi | 87% | 3337 fps | 99.4% |
| ADI AR 2217 | <<locked>> | 96% | 54,563 psi | 86% | 3304 fps | 99.6% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 55,332 psi | 87% | 3415 fps | 97.4% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 57,392 psi | 90% | 3389 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 57,522 psi | 90% | 3320 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 82% | 57,421 psi | 90% | 3317 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 56,898 psi | 89% | 3310 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 88% | 56,275 psi | 88% | 3330 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 88% | 54,317 psi | 85% | 3238 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 54,766 psi | 86% | 3314 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 54,998 psi | 86% | 3327 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 57,130 psi | 90% | 3399 fps | 97.6% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 56,666 psi | 89% | 3291 fps | 97.7% |
| Bofors RP15 | <<locked>> | 90% | 55,622 psi | 87% | 3317 fps | 99.8% |
| Bofors RP30 | <<locked>> | 94% | 54,534 psi | 85% | 3317 fps | 99.5% |
| Bofors RP5 | <<locked>> | 88% | 56,275 psi | 88% | 3330 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 94% | 56,173 psi | 88% | 3330 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 86% | 55,056 psi | 86% | 3264 fps | 98.9% |
| Hodgdon H4831 SC | <<locked>> | 88% | 57,696 psi | 90% | 3310 fps | 99.2% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 57,580 psi | 90% | 3232 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 57,624 psi | 90% | 3465 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,623 psi | 59% | 2152 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 55,840 psi | 88% | 3238 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 56,550 psi | 89% | 3245 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 55,405 psi | 87% | 3241 fps | 99% |
| IMR 7828 SSC | <<locked>> | 88% | 54,273 psi | 85% | 3317 fps | 99.3% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 52,562 psi | 82% | 3294 fps | 99.3% |
| Lovex S071 | <<locked>> | 92% | 54,375 psi | 85% | 3202 fps | 100% |
| Norma 204 | <<locked>> | 82% | 57,232 psi | 90% | 3304 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 53,722 psi | 84% | 3327 fps | 100% |
| Norma MRP | <<locked>> | 86% | 56,405 psi | 88% | 3350 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 55,477 psi | 87% | 3340 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 82% | 57,217 psi | 90% | 3297 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 54,056 psi | 85% | 3261 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,508 psi | 60% | 2201 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 54,636 psi | 86% | 3383 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 54,114 psi | 85% | 3333 fps | 98.7% |
| Rottweil R 904 | <<locked>> | 84% | 54,288 psi | 85% | 3232 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 86% | 56,710 psi | 89% | 3307 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 56,318 psi | 88% | 3301 fps | 99.9% |
| Somchem S361 | <<locked>> | 84% | 55,695 psi | 87% | 3215 fps | 99% |
| Somchem S365 | <<locked>> | 82% | 55,898 psi | 88% | 3235 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 57,058 psi | 89% | 3271 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 57,043 psi | 89% | 3251 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 56,231 psi | 88% | 3271 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 55,825 psi | 87% | 3346 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 92% | 56,913 psi | 89% | 3337 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 94% | 54,607 psi | 86% | 3340 fps | 98.3% |
| Vihtavuori N570 | <<locked>> | 96% | 55,796 psi | 87% | 3406 fps | 96.9% |
| Winchester StaBALL HD | <<locked>> | 88% | 54,157 psi | 85% | 3327 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 57,130 psi | 90% | 3268 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% | 42,873 psi | 67% | 2982 fps | 99.6% |
| Accurate High Country | <<locked>> | 80% | 47,050 psi | 74% | 3186 fps | 98% |
| Accurate MAGPRO | <<locked>> | 80% | 44,556 psi | 70% | 3117 fps | 96.2% |
| ADI AR 2209 | <<locked>> | 80% | 46,862 psi | 73% | 3130 fps | 98.8% |
| ADI AR 2213 | <<locked>> | 80% | 42,148 psi | 66% | 3058 fps | 96.7% |
| ADI AR 2217 | <<locked>> | 86% | 38,595 psi | 60% | 2963 fps | 95.9% |
| ADI AR 2218 | <<locked>> | 96% | 47,601 psi | 75% | 3248 fps | 95% |
| ADI AR 2225 | <<locked>> | 82% | 30,821 psi | 48% | 2779 fps | 95.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 47,239 psi | 74% | 3130 fps | 98.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 53,824 psi | 84% | 3261 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,804 psi | 73% | 3123 fps | 98.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,888 psi | 67% | 3064 fps | 98.1% |
| Alliant Reloder-23 | <<locked>> | 80% | 41,582 psi | 65% | 3005 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,969 psi | 56% | 2923 fps | 99.1% |
| Alliant Reloder-26 | <<locked>> | 80% | 47,137 psi | 74% | 3186 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 48,936 psi | 77% | 3241 fps | 95.6% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 46,557 psi | 73% | 3087 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 39,885 psi | 63% | 2989 fps | 97.1% |
| Bofors RP30 | <<locked>> | 82% | 35,998 psi | 56% | 2910 fps | 95% |
| Bofors RP5 | <<locked>> | 80% | 42,888 psi | 67% | 3064 fps | 98.1% |
| Hodgdon H1000 | <<locked>> | 82% | 36,608 psi | 57% | 2913 fps | 95.8% |
| Hodgdon H4831 | <<locked>> | 80% | 44,744 psi | 70% | 3061 fps | 96.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 43,976 psi | 69% | 3041 fps | 96.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 50,575 psi | 79% | 3117 fps | 100% |
| Hodgdon Retumbo | 92.4 gr | 80% | 35,114 psi | 55% | 2956 fps | 96.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,268 psi | 44% | 1932 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 52,518 psi | 82% | 3179 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 53,084 psi | 83% | 3186 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,774 psi | 72% | 3051 fps | 97.3% |
| IMR 7828 SSC | <<locked>> | 80% | 40,857 psi | 64% | 3035 fps | 96.3% |
| IMR 8133 Enduron | <<locked>> | 90% | 37,159 psi | 58% | 2956 fps | 95.3% |
| Lovex S071 | <<locked>> | 80% | 36,869 psi | 58% | 2844 fps | 98.5% |
| Norma 204 | <<locked>> | 80% | 53,534 psi | 84% | 3235 fps | 99.6% |
| Norma 217 | <<locked>> | 86% | 32,518 psi | 51% | 2844 fps | 95.6% |
| Norma MRP | <<locked>> | 80% | 45,614 psi | 71% | 3146 fps | 99.5% |
| Ramshot Grand | <<locked>> | 80% | 40,915 psi | 64% | 3045 fps | 96.8% |
| Ramshot Hunter | <<locked>> | 80% | 53,621 psi | 84% | 3238 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 36,898 psi | 58% | 2907 fps | 97.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,993 psi | 45% | 1978 fps | 100% |
| ReloadSwiss RS 76 | 98.8 gr | 80% | 34,418 psi | 54% | 2923 fps | 97.3% |
| ReloadSwiss RS 80 | 109.6 gr | 88% | 42,888 psi | 67% | 3100 fps | 95.9% |
| Rottweil R 904 | <<locked>> | 80% | 47,659 psi | 75% | 3104 fps | 98.2% |
| Rottweil R 905 | <<locked>> | 80% | 46,383 psi | 73% | 3110 fps | 98.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 46,035 psi | 72% | 3104 fps | 98.8% |
| Somchem S361 | <<locked>> | 80% | 48,791 psi | 76% | 3087 fps | 97.8% |
| Somchem S365 | <<locked>> | 80% | 52,330 psi | 82% | 3182 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,862 psi | 73% | 3084 fps | 99.4% |
| Vihtavuori N165 | <<locked>> | 80% | 40,901 psi | 64% | 2943 fps | 98.1% |
| Vihtavuori N555 | <<locked>> | 80% | 46,195 psi | 72% | 3094 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 45,295 psi | 71% | 3136 fps | 97.1% |
| Vihtavuori N565 | <<locked>> | 82% | 40,263 psi | 63% | 2995 fps | 95.8% |
| Vihtavuori N568 | <<locked>> | 88% | 43,918 psi | 69% | 3117 fps | 95.6% |
| Vihtavuori N570 | <<locked>> | 94% | 51,866 psi | 81% | 3327 fps | 96% |
| Winchester StaBALL HD | <<locked>> | 80% | 39,740 psi | 62% | 3061 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 43,192 psi | 68% | 3005 fps | 98.1% |
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 55 powders for .30-378 Weath. Mag. loaded with the .308 | 155gr | Norma GTX. Hodgdon Retumbo delivers the highest muzzle velocity at 3,465 fps; across all powders the maximum-charge window runs from 2,152 fps to 3,465 fps. ADI AR 2218 gives the best case fill at 100 %, and 55 of the 55 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 155.0 gr projectile in 0.308" calls for a 1:13.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, Hodgdon TrailBoss 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. Hodgdon Retumbo, ReloadSwiss RS 76, ReloadSwiss RS 80 rank at the top here: for .30-378 Weath. Mag. with the .308 | 155gr | Norma GTX 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.