Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 120gr | Remington PSP Core-Lokt bullet and 67 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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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 90% | 55,651 psi | 87% | 3087 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 56,376 psi | 88% | 3114 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 54,404 psi | 85% | 3192 fps | 98.6% |
| ADI AR 2209 | <<locked>> | 88% | 57,246 psi | 90% | 3186 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 90% | 55,274 psi | 87% | 3192 fps | 99.4% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 57,421 psi | 90% | 3222 fps | 99.8% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 52,011 psi | 82% | 3182 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 57,493 psi | 90% | 3176 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 56,695 psi | 89% | 3169 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 90% | 55,680 psi | 87% | 3189 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 92% | 57,217 psi | 90% | 3150 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 57,232 psi | 90% | 3225 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 54,070 psi | 85% | 3189 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 55,071 psi | 86% | 3251 fps | 97.3% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 56,289 psi | 88% | 3150 fps | 97.6% |
| Bofors RP15 | <<locked>> | 92% | 54,882 psi | 86% | 3176 fps | 99.8% |
| Bofors RP30 | <<locked>> | 98% | 57,072 psi | 89% | 3235 fps | 99.8% |
| Bofors RP5 | <<locked>> | 90% | 55,680 psi | 87% | 3189 fps | 99.9% |
| Bofors RP7 | <<locked>> | 82% | 57,580 psi | 90% | 3114 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 55,085 psi | 86% | 3182 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 82% | 57,711 psi | 90% | 3173 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 54,781 psi | 86% | 3123 fps | 98.9% |
| Hodgdon H4831 SC | <<locked>> | 90% | 57,450 psi | 90% | 3169 fps | 99.2% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 57,435 psi | 90% | 3087 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 56,057 psi | 88% | 3310 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,492 psi | 59% | 2005 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 56,202 psi | 88% | 3104 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 56,579 psi | 89% | 3104 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 55,535 psi | 87% | 3104 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 92% | 57,363 psi | 90% | 3235 fps | 99.6% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 47,558 psi | 75% | 3087 fps | 98.7% |
| Lovex S065 | <<locked>> | 82% | 56,333 psi | 88% | 3077 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 54,911 psi | 86% | 3077 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 57,261 psi | 90% | 3114 fps | 100% |
| Norma 204 | <<locked>> | 84% | 57,261 psi | 90% | 3163 fps | 99.9% |
| Norma 217ᴾ | <<locked>> | 100% | 48,066 psi | 75% | 3114 fps | 99.9% |
| Norma MRP | <<locked>> | 88% | 55,666 psi | 87% | 3209 fps | 100% |
| Norma URP | <<locked>> | 82% | 54,679 psi | 86% | 3097 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 54,331 psi | 85% | 3192 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 84% | 57,087 psi | 89% | 3156 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 56,985 psi | 89% | 3182 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,290 psi | 60% | 2047 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 56,623 psi | 89% | 3140 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 55,042 psi | 86% | 3166 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 57,072 psi | 89% | 3304 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 56,652 psi | 89% | 3264 fps | 99.2% |
| Rottweil R 904 | <<locked>> | 86% | 54,476 psi | 85% | 3091 fps | 99.3% |
| Rottweil R 905 | <<locked>> | 88% | 56,565 psi | 89% | 3163 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 82% | 57,580 psi | 90% | 3114 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 56,333 psi | 88% | 3077 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 54,911 psi | 86% | 3077 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 55,361 psi | 87% | 3025 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 56,159 psi | 88% | 3159 fps | 99.9% |
| Somchem S361 | <<locked>> | 86% | 55,869 psi | 88% | 3081 fps | 99% |
| Somchem S365 | <<locked>> | 84% | 55,738 psi | 87% | 3100 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 56,869 psi | 89% | 3130 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 56,159 psi | 88% | 3084 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 56,811 psi | 89% | 3114 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 55,274 psi | 87% | 3087 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 55,651 psi | 87% | 3127 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 55,230 psi | 87% | 3205 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 94% | 55,956 psi | 88% | 3196 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 98% | 57,159 psi | 90% | 3264 fps | 98.8% |
| Vihtavuori N570 | <<locked>> | 98% | 54,114 psi | 85% | 3255 fps | 96.7% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 55,608 psi | 87% | 3031 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 56,811 psi | 89% | 3245 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 56,811 psi | 89% | 3127 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% | 39,798 psi | 62% | 2799 fps | 99.3% |
| Accurate 4350 | <<locked>> | 80% | 52,678 psi | 83% | 3058 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 40,901 psi | 64% | 2917 fps | 95.3% |
| ADI AR 2209 | <<locked>> | 80% | 43,787 psi | 69% | 2936 fps | 98.4% |
| ADI AR 2213 | <<locked>> | 80% | 39,160 psi | 61% | 2861 fps | 95.9% |
| ADI AR 2217 | <<locked>> | 86% | 35,752 psi | 56% | 2772 fps | 95% |
| ADI AR 2225 | <<locked>> | 84% | 30,342 psi | 48% | 2661 fps | 95.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 50,285 psi | 79% | 3058 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 43,787 psi | 69% | 2927 fps | 98.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 39,726 psi | 62% | 2871 fps | 97.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 38,522 psi | 60% | 2822 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 33,228 psi | 52% | 2740 fps | 98.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 43,033 psi | 67% | 2989 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 47,210 psi | 74% | 3097 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 46,601 psi | 73% | 2959 fps | 95.2% |
| Bofors RP15 | <<locked>> | 80% | 36,999 psi | 58% | 2802 fps | 96.5% |
| Bofors RP30 | <<locked>> | 84% | 35,288 psi | 55% | 2785 fps | 95.1% |
| Bofors RP5 | <<locked>> | 80% | 39,726 psi | 62% | 2871 fps | 97.5% |
| Bofors RP7 | <<locked>> | 80% | 54,041 psi | 85% | 3054 fps | 100% |
| Hodgdon H1000 | <<locked>> | 84% | 36,361 psi | 57% | 2789 fps | 96% |
| Hodgdon H414 | <<locked>> | 80% | 54,143 psi | 85% | 3117 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 41,785 psi | 65% | 2867 fps | 96.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 40,988 psi | 64% | 2848 fps | 95.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 47,268 psi | 74% | 2927 fps | 100% |
| Hodgdon Retumbo | 56.8 gr | 80% | 32,430 psi | 51% | 2766 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,036 psi | 44% | 1791 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 49,545 psi | 78% | 2986 fps | 99.7% |
| IMR 4831 | <<locked>> | 80% | 49,719 psi | 78% | 2992 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 43,091 psi | 68% | 2864 fps | 96.7% |
| IMR 7828 SSC | <<locked>> | 80% | 37,768 psi | 59% | 2838 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 92% | 35,998 psi | 56% | 2825 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 53,142 psi | 83% | 3025 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 51,547 psi | 81% | 3018 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 34,243 psi | 54% | 2664 fps | 98.1% |
| Norma 204 | <<locked>> | 80% | 50,009 psi | 78% | 3035 fps | 99.3% |
| Norma 217 | <<locked>> | 88% | 31,676 psi | 50% | 2726 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 41,872 psi | 66% | 2946 fps | 99.1% |
| Norma URP | <<locked>> | 80% | 51,213 psi | 80% | 3038 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 37,492 psi | 59% | 2844 fps | 95.9% |
| Ramshot Hunter | <<locked>> | 80% | 50,009 psi | 78% | 3038 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 33,678 psi | 53% | 2717 fps | 96.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,805 psi | 45% | 1837 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 52,794 psi | 83% | 3077 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 51,198 psi | 80% | 3107 fps | 100% |
| ReloadSwiss RS 76 | 60.8 gr | 80% | 31,560 psi | 49% | 2733 fps | 96.3% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 41,495 psi | 65% | 2969 fps | 95.8% |
| Rottweil R 904 | <<locked>> | 80% | 44,846 psi | 70% | 2910 fps | 97.7% |
| Rottweil R 905 | <<locked>> | 80% | 43,120 psi | 68% | 2913 fps | 98.4% |
| Rottweil R 907 | <<locked>> | 80% | 54,041 psi | 85% | 3054 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 53,142 psi | 83% | 3025 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 51,547 psi | 81% | 3018 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 51,909 psi | 81% | 2969 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 42,786 psi | 67% | 2907 fps | 98.3% |
| Somchem S361 | <<locked>> | 80% | 45,759 psi | 72% | 2897 fps | 97.2% |
| Somchem S365 | <<locked>> | 80% | 48,704 psi | 76% | 2989 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 43,743 psi | 69% | 2894 fps | 99% |
| Vihtavuori N160 | <<locked>> | 80% | 52,620 psi | 82% | 3028 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,101 psi | 60% | 2759 fps | 97.6% |
| Vihtavuori N550 | <<locked>> | 80% | 51,880 psi | 81% | 3035 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 42,931 psi | 67% | 2904 fps | 100% |
| Vihtavuori N560 | 58.9 gr | 80% | 41,742 psi | 65% | 2936 fps | 96.3% |
| Vihtavuori N565 | <<locked>> | 84% | 39,682 psi | 62% | 2867 fps | 95.9% |
| Vihtavuori N568 | <<locked>> | 90% | 42,699 psi | 67% | 2986 fps | 95.6% |
| Vihtavuori N570 | <<locked>> | 96% | 50,227 psi | 79% | 3179 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 51,953 psi | 81% | 2979 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 35,578 psi | 56% | 2864 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 40,205 psi | 63% | 2815 fps | 97.6% |
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 74 powders for .257 Weath. Mag. loaded with the .257 | 120gr | Remington PSP Core-Lokt. Hodgdon Retumbo delivers the highest muzzle velocity at 3,310 fps; across all powders the maximum-charge window runs from 2,005 fps to 3,310 fps. ADI AR 2217 gives the best case fill at 100 %, and 74 of the 74 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 120.0 gr projectile in 0.257" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, 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. Hodgdon Retumbo, ReloadSwiss RS 76, Vihtavuori N560 rank at the top here: for .257 Weath. Mag. with the .257 | 120gr | Remington PSP Core-Lokt they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-50, 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.