Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 110gr | Sierra Tipped GameKing bullet and 72 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 Vihtavuori N560.
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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You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 92% | 55,332 psi | 87% | 3199 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 56,217 psi | 88% | 3235 fps | 100% |
| Accurate High Country | <<locked>> | 90% | 57,116 psi | 90% | 3366 fps | 99.2% |
| Accurate MAGPRO | <<locked>> | 90% | 54,099 psi | 85% | 3297 fps | 97.8% |
| ADI AR 2209 | <<locked>> | 90% | 57,203 psi | 90% | 3301 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 92% | 54,998 psi | 86% | 3301 fps | 98.8% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 53,229 psi | 83% | 3258 fps | 98.9% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 47,674 psi | 75% | 3212 fps | 99.9% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 57,261 psi | 90% | 3294 fps | 99.6% |
| Alliant Reloder-16 | <<locked>> | 86% | 57,058 psi | 89% | 3297 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 56,579 psi | 89% | 3284 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 92% | 55,274 psi | 87% | 3297 fps | 99.6% |
| Alliant Reloder-23 | <<locked>> | 94% | 56,739 psi | 89% | 3268 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 56,188 psi | 88% | 3333 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 57,305 psi | 90% | 3363 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 56,492 psi | 89% | 3255 fps | 96.7% |
| Bofors RP15 | <<locked>> | 94% | 54,476 psi | 85% | 3281 fps | 99.4% |
| Bofors RP30ᴾ | <<locked>> | 100% | 56,028 psi | 88% | 3337 fps | 99.3% |
| Bofors RP5 | <<locked>> | 92% | 55,274 psi | 87% | 3297 fps | 99.6% |
| Bofors RP7 | <<locked>> | 82% | 54,389 psi | 85% | 3173 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 98% | 54,737 psi | 86% | 3287 fps | 99.4% |
| Hodgdon H414 | <<locked>> | 84% | 57,667 psi | 90% | 3291 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 56,376 psi | 88% | 3245 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 90% | 54,737 psi | 86% | 3232 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 92% | 57,450 psi | 90% | 3278 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 57,421 psi | 90% | 3209 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 55,158 psi | 86% | 3415 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 54,404 psi | 85% | 3261 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,289 psi | 58% | 2080 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 56,362 psi | 88% | 3219 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 82% | 55,796 psi | 87% | 3199 fps | 99.9% |
| IMR 4831 | <<locked>> | 86% | 56,507 psi | 89% | 3225 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 55,709 psi | 87% | 3219 fps | 98.5% |
| IMR 7828 SSC | <<locked>> | 94% | 56,898 psi | 89% | 3346 fps | 99.1% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 43,192 psi | 68% | 3104 fps | 96.8% |
| Lovex S065 | <<locked>> | 84% | 56,637 psi | 89% | 3199 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 54,839 psi | 86% | 3192 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 56,695 psi | 89% | 3222 fps | 100% |
| Norma 204 | <<locked>> | 86% | 57,609 psi | 90% | 3284 fps | 99.6% |
| Norma 217ᴾ | <<locked>> | 100% | 43,555 psi | 68% | 3133 fps | 98.9% |
| Norma MRP | <<locked>> | 90% | 55,347 psi | 87% | 3320 fps | 100% |
| Norma URP | <<locked>> | 84% | 54,389 psi | 85% | 3212 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 53,882 psi | 84% | 3301 fps | 99% |
| Ramshot Hunter | <<locked>> | 86% | 57,232 psi | 90% | 3281 fps | 100% |
| Ramshot Magnum | <<locked>> | 96% | 56,608 psi | 89% | 3294 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,029 psi | 60% | 2126 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 56,333 psi | 88% | 3258 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 54,578 psi | 86% | 3284 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 56,289 psi | 88% | 3412 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 55,535 psi | 87% | 3360 fps | 98.4% |
| Rottweil R 904 | <<locked>> | 88% | 54,346 psi | 85% | 3199 fps | 98.7% |
| Rottweil R 905 | <<locked>> | 90% | 56,130 psi | 88% | 3271 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 82% | 54,389 psi | 85% | 3173 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 84% | 56,637 psi | 89% | 3199 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 54,839 psi | 86% | 3192 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 55,738 psi | 87% | 3146 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 55,709 psi | 87% | 3268 fps | 99.6% |
| Somchem S361 | <<locked>> | 88% | 55,956 psi | 88% | 3189 fps | 98.4% |
| Somchem S365 | <<locked>> | 86% | 55,376 psi | 87% | 3219 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 56,724 psi | 89% | 3241 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 82% | 56,811 psi | 89% | 3136 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 56,202 psi | 88% | 3205 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 56,347 psi | 88% | 3219 fps | 99.8% |
| Vihtavuori N550 | <<locked>> | 84% | 55,521 psi | 87% | 3212 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 55,187 psi | 86% | 3241 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 55,013 psi | 86% | 3314 fps | 98.5% |
| Vihtavuori N565 | <<locked>> | 96% | 55,042 psi | 86% | 3291 fps | 98.7% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 56,289 psi | 88% | 3363 fps | 98% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 55,825 psi | 87% | 3153 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 54,056 psi | 85% | 3232 fps | 99.9% |
| Winchester StaBALL HD | <<locked>> | 94% | 55,317 psi | 87% | 3360 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 56,739 psi | 89% | 3235 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 3100 | <<locked>> | 80% | 36,782 psi | 58% | 2828 fps | 98% |
| Accurate 4350 | <<locked>> | 80% | 49,023 psi | 77% | 3114 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 39,900 psi | 63% | 3009 fps | 95.3% |
| Accurate MAGPRO | <<locked>> | 84% | 43,569 psi | 68% | 3081 fps | 95.1% |
| ADI AR 2209 | <<locked>> | 80% | 40,741 psi | 64% | 2972 fps | 96.7% |
| ADI AR 2213 | <<locked>> | 84% | 41,684 psi | 65% | 3025 fps | 95.7% |
| ADI AR 2217 | <<locked>> | 92% | 40,422 psi | 63% | 2986 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 88% | 31,952 psi | 50% | 2802 fps | 95.3% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 41,191 psi | 65% | 2976 fps | 96.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 46,746 psi | 73% | 3117 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 40,814 psi | 64% | 2966 fps | 96.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 36,680 psi | 57% | 2900 fps | 95.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 35,404 psi | 55% | 2861 fps | 99.9% |
| Alliant Reloder-25 | <<locked>> | 80% | 30,676 psi | 48% | 2759 fps | 96.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 39,218 psi | 61% | 3022 fps | 99.6% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 49,777 psi | 78% | 3123 fps | 95% |
| Bofors RP15 | <<locked>> | 82% | 36,564 psi | 57% | 2894 fps | 95.2% |
| Bofors RP30 | <<locked>> | 90% | 39,726 psi | 62% | 3002 fps | 95.8% |
| Bofors RP5 | <<locked>> | 80% | 36,680 psi | 57% | 2900 fps | 95.4% |
| Bofors RP7 | <<locked>> | 80% | 50,995 psi | 80% | 3110 fps | 99.5% |
| Hodgdon H1000 | <<locked>> | 88% | 38,624 psi | 61% | 2943 fps | 95.6% |
| Hodgdon H414 | <<locked>> | 80% | 50,386 psi | 79% | 3166 fps | 99.7% |
| Hodgdon H4350 | <<locked>> | 80% | 52,881 psi | 83% | 3182 fps | 99.3% |
| Hodgdon H4831 | <<locked>> | 82% | 41,611 psi | 65% | 2966 fps | 95% |
| Hodgdon H4831 SC | <<locked>> | 84% | 43,700 psi | 68% | 3012 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 44,005 psi | 69% | 2986 fps | 100% |
| Hodgdon Retumbo | 60.7 gr | 86% | 36,550 psi | 57% | 2986 fps | 96.1% |
| Hodgdon Superformance | <<locked>> | 80% | 50,647 psi | 79% | 3196 fps | 99.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,818 psi | 44% | 1860 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 46,557 psi | 73% | 3038 fps | 98.9% |
| IMR 4451 Enduron | <<locked>> | 80% | 52,388 psi | 82% | 3140 fps | 99.8% |
| IMR 4831 | <<locked>> | 80% | 46,412 psi | 73% | 3051 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 43,163 psi | 68% | 2966 fps | 95.7% |
| IMR 7828 SSC | <<locked>> | 84% | 40,147 psi | 63% | 2999 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 98% | 40,277 psi | 63% | 3035 fps | 95.8% |
| Lovex S065 | <<locked>> | 80% | 50,096 psi | 79% | 3087 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 48,457 psi | 76% | 3074 fps | 99.5% |
| Lovex S071 | <<locked>> | 80% | 31,604 psi | 50% | 2694 fps | 96.2% |
| Norma 204 | <<locked>> | 80% | 46,775 psi | 73% | 3081 fps | 98.1% |
| Norma 217 | <<locked>> | 92% | 32,967 psi | 52% | 2861 fps | 95.2% |
| Norma MRP | <<locked>> | 80% | 38,508 psi | 60% | 2976 fps | 97.5% |
| Norma URP | <<locked>> | 80% | 47,863 psi | 75% | 3097 fps | 100% |
| Ramshot Grand | <<locked>> | 84% | 39,943 psi | 63% | 3005 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 46,688 psi | 73% | 3091 fps | 99.7% |
| Ramshot Magnum | <<locked>> | 82% | 33,330 psi | 52% | 2802 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,529 psi | 45% | 1906 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 49,124 psi | 77% | 3133 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 47,137 psi | 74% | 3153 fps | 100% |
| ReloadSwiss RS 76 | 63.5 gr | 84% | 33,489 psi | 52% | 2884 fps | 96% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 43,874 psi | 69% | 3127 fps | 95.5% |
| Rottweil R 904 | <<locked>> | 80% | 42,003 psi | 66% | 2949 fps | 95.9% |
| Rottweil R 905 | <<locked>> | 80% | 40,219 psi | 63% | 2953 fps | 96.8% |
| Rottweil R 907 | <<locked>> | 80% | 50,995 psi | 80% | 3110 fps | 99.5% |
| Shooters World Long Rifle | <<locked>> | 80% | 50,096 psi | 79% | 3087 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 48,457 psi | 76% | 3074 fps | 99.5% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 48,994 psi | 77% | 3025 fps | 99.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 39,929 psi | 63% | 2946 fps | 96.6% |
| Somchem S361 | <<locked>> | 80% | 42,743 psi | 67% | 2933 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 45,063 psi | 71% | 3045 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 40,756 psi | 64% | 2933 fps | 97.7% |
| Vihtavuori N150 | <<locked>> | 80% | 53,214 psi | 83% | 3084 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 49,284 psi | 77% | 3087 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 35,360 psi | 55% | 2789 fps | 95.6% |
| Vihtavuori N550 | <<locked>> | 80% | 48,631 psi | 76% | 3091 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 39,624 psi | 62% | 2946 fps | 99.8% |
| Vihtavuori N560 | 60.1 gr | 82% | 41,437 psi | 65% | 3035 fps | 95.1% |
| Vihtavuori N565 | <<locked>> | 88% | 41,959 psi | 66% | 3028 fps | 95.6% |
| Vihtavuori N568 | <<locked>> | 94% | 45,034 psi | 71% | 3143 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 48,646 psi | 76% | 3038 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 50,604 psi | 79% | 3169 fps | 99.7% |
| Winchester StaBALL HD | <<locked>> | 80% | 31,705 psi | 50% | 2884 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 37,347 psi | 59% | 2848 fps | 95.7% |
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 72 powders for .257 Weath. Mag. loaded with the .257 | 110gr | Sierra Tipped GameKing. Hodgdon Retumbo delivers the highest muzzle velocity at 3,415 fps; across all powders the maximum-charge window runs from 2,080 fps to 3,415 fps. ADI AR 2217 gives the best case fill at 100 %, and 72 of the 72 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 58–90 %, leaving at least 10 % headroom. The 110.0 gr projectile in 0.257" calls for a 1:9.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Bofors RP30 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, Vihtavuori N560 rank at the top here: for .257 Weath. Mag. with the .257 | 110gr | Sierra Tipped 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.