Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 87gr | Berger Target FB bullet and 79 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N560, Norma MRP and ReloadSwiss RS 70.
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 2700 | <<locked>> | 84% | 56,130 psi | 88% | 3451 fps | 98.8% |
| Accurate 3100 | <<locked>> | 96% | 55,158 psi | 86% | 3501 fps | 99.6% |
| Accurate 4350 | <<locked>> | 88% | 56,391 psi | 88% | 3563 fps | 100% |
| ADI AR 2208 | <<locked>> | 84% | 57,566 psi | 90% | 3533 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 57,435 psi | 90% | 3615 fps | 98.4% |
| ADI AR 2213 | <<locked>> | 96% | 55,332 psi | 87% | 3606 fps | 97% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,118 psi | 64% | 3320 fps | 96.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 55,332 psi | 87% | 3501 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 56,913 psi | 89% | 3629 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 54,621 psi | 86% | 3586 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 56,724 psi | 89% | 3593 fps | 98.3% |
| Alliant Reloder-22 | <<locked>> | 96% | 55,085 psi | 86% | 3602 fps | 98.2% |
| Alliant Reloder-23 | <<locked>> | 98% | 55,898 psi | 88% | 3583 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 51,750 psi | 81% | 3570 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 94% | 56,826 psi | 89% | 3681 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 57,653 psi | 90% | 3645 fps | 98.5% |
| Bofors RP3 | <<locked>> | 82% | 56,376 psi | 88% | 3517 fps | 100% |
| Bofors RP5 | <<locked>> | 96% | 55,085 psi | 86% | 3602 fps | 98.2% |
| Bofors RP7 | <<locked>> | 86% | 55,477 psi | 87% | 3501 fps | 98.8% |
| Hodgdon H380 | <<locked>> | 82% | 56,405 psi | 88% | 3533 fps | 100% |
| Hodgdon H414 | <<locked>> | 84% | 55,550 psi | 87% | 3570 fps | 99.2% |
| Hodgdon H4350 | <<locked>> | 88% | 55,709 psi | 87% | 3543 fps | 98.3% |
| Hodgdon H4831 | <<locked>> | 98% | 54,346 psi | 85% | 3517 fps | 96.1% |
| Hodgdon H4831 SC | <<locked>> | 94% | 54,085 psi | 85% | 3510 fps | 96% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 57,421 psi | 90% | 3537 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 50,691 psi | 79% | 3622 fps | 98.3% |
| Hodgdon Superformance | <<locked>> | 86% | 55,027 psi | 86% | 3583 fps | 99% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,651 psi | 57% | 2316 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 57,014 psi | 89% | 3524 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,434 psi | 88% | 3507 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 55,056 psi | 86% | 3478 fps | 99.1% |
| IMR 4350 | <<locked>> | 90% | 57,029 psi | 89% | 3540 fps | 99% |
| IMR 4451 Enduron | <<locked>> | 86% | 56,971 psi | 89% | 3533 fps | 99.3% |
| IMR 4831 | <<locked>> | 92% | 54,389 psi | 85% | 3510 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 56,405 psi | 88% | 3524 fps | 96.7% |
| IMR 7828 SSC | <<locked>> | 96% | 57,058 psi | 89% | 3652 fps | 97.5% |
| Lovex S062 | <<locked>> | 82% | 57,246 psi | 90% | 3507 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 57,493 psi | 90% | 3530 fps | 99.8% |
| Lovex S070 | <<locked>> | 88% | 55,608 psi | 87% | 3517 fps | 99.3% |
| Lovex S071ᴾ | <<locked>> | 100% | 52,620 psi | 82% | 3455 fps | 99.4% |
| Norma 204 | <<locked>> | 88% | 54,447 psi | 85% | 3530 fps | 97.7% |
| Norma MRP | <<locked>> | 94% | 54,781 psi | 86% | 3625 fps | 99.2% |
| Norma URP | <<locked>> | 88% | 54,781 psi | 86% | 3543 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 56,956 psi | 89% | 3655 fps | 97.8% |
| Ramshot Hunter | <<locked>> | 90% | 57,624 psi | 90% | 3606 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 96% | 54,099 psi | 85% | 3550 fps | 98.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,434 psi | 59% | 2372 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 56,173 psi | 88% | 3514 fps | 99.5% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 53,751 psi | 84% | 3573 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 56,391 psi | 88% | 3579 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 54,969 psi | 86% | 3615 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 51,561 psi | 81% | 3619 fps | 99.3% |
| Rottweil R 903 | <<locked>> | 84% | 56,478 psi | 89% | 3514 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 54,868 psi | 86% | 3507 fps | 96.9% |
| Rottweil R 905 | <<locked>> | 94% | 56,173 psi | 88% | 3583 fps | 98.4% |
| Rottweil R 907 | <<locked>> | 86% | 55,477 psi | 87% | 3501 fps | 98.8% |
| Shooters World Long Rifle | <<locked>> | 88% | 57,493 psi | 90% | 3530 fps | 99.8% |
| Shooters World Precision | <<locked>> | 82% | 57,246 psi | 90% | 3507 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 55,608 psi | 87% | 3517 fps | 99.3% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 54,534 psi | 85% | 3517 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 56,666 psi | 89% | 3379 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 56,971 psi | 89% | 3471 fps | 99.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 55,709 psi | 87% | 3573 fps | 98.3% |
| Somchem S355 | <<locked>> | 84% | 56,072 psi | 88% | 3510 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 57,145 psi | 90% | 3494 fps | 96.7% |
| Somchem S365 | <<locked>> | 90% | 54,955 psi | 86% | 3543 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 56,927 psi | 89% | 3550 fps | 99% |
| Unknown powder | <<locked>> | 86% | 54,911 psi | 86% | 3547 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 88% | 54,723 psi | 86% | 3435 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 55,376 psi | 87% | 3507 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 54,592 psi | 86% | 3484 fps | 98.5% |
| Vihtavuori N550 | <<locked>> | 86% | 56,028 psi | 88% | 3566 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 54,476 psi | 85% | 3553 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 55,230 psi | 87% | 3625 fps | 96.6% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 54,650 psi | 86% | 3576 fps | 96.7% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 56,797 psi | 89% | 3484 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 55,550 psi | 87% | 3570 fps | 99.2% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 57,609 psi | 90% | 3737 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 54,795 psi | 86% | 3501 fps | 98% |
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 2700 | <<locked>> | 80% | 49,182 psi | 77% | 3317 fps | 97.6% |
| Accurate 3100 | <<locked>> | 84% | 36,347 psi | 57% | 3091 fps | 95.6% |
| Accurate 4350 | <<locked>> | 80% | 42,583 psi | 67% | 3284 fps | 98.8% |
| ADI AR 2208 | <<locked>> | 80% | 50,792 psi | 80% | 3412 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 86% | 43,729 psi | 69% | 3323 fps | 95.1% |
| ADI AR 2213 | <<locked>> | 92% | 48,008 psi | 75% | 3448 fps | 95% |
| ADI AR 2225 | <<locked>> | 98% | 38,435 psi | 60% | 3241 fps | 95.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 51,706 psi | 81% | 3438 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 40,814 psi | 64% | 3294 fps | 98.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 47,079 psi | 74% | 3445 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 43,526 psi | 68% | 3314 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 90% | 44,759 psi | 70% | 3383 fps | 95.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 30,211 psi | 47% | 2986 fps | 96.8% |
| Alliant Reloder-25 | <<locked>> | 88% | 34,534 psi | 54% | 3133 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 32,909 psi | 52% | 3120 fps | 95.5% |
| Bofors RP15 | <<locked>> | 92% | 44,164 psi | 69% | 3363 fps | 95.3% |
| Bofors RP3 | <<locked>> | 80% | 52,620 psi | 82% | 3455 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 44,759 psi | 70% | 3383 fps | 95.7% |
| Bofors RP7 | <<locked>> | 80% | 45,701 psi | 72% | 3297 fps | 96.9% |
| Hodgdon H380 | <<locked>> | 80% | 52,692 psi | 83% | 3468 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 80% | 48,211 psi | 76% | 3425 fps | 98% |
| Hodgdon H4350 | <<locked>> | 80% | 43,062 psi | 67% | 3271 fps | 95.3% |
| Hodgdon H4831 | <<locked>> | 96% | 50,865 psi | 80% | 3448 fps | 95.2% |
| Hodgdon H4831 SC | <<locked>> | 92% | 50,401 psi | 79% | 3438 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 38,406 psi | 60% | 3159 fps | 99.2% |
| Hodgdon Retumbo | <<locked>> | 94% | 41,278 psi | 65% | 3379 fps | 95% |
| Hodgdon Superformance | <<locked>> | 80% | 43,845 psi | 69% | 3350 fps | 96.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,383 psi | 43% | 2083 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,534 psi | 84% | 3465 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,661 psi | 78% | 3383 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 80% | 48,602 psi | 76% | 3350 fps | 98% |
| IMR 4350 | <<locked>> | 80% | 41,307 psi | 65% | 3205 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 80% | 47,108 psi | 74% | 3337 fps | 97.6% |
| IMR 4831 | <<locked>> | 80% | 36,753 psi | 58% | 3120 fps | 97.5% |
| IMR 4955 Enduron | <<locked>> | 90% | 49,588 psi | 78% | 3389 fps | 95.1% |
| IMR 7828 SSC | <<locked>> | 92% | 49,429 psi | 77% | 3494 fps | 95.6% |
| Lovex S062 | <<locked>> | 80% | 53,780 psi | 84% | 3448 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 44,628 psi | 70% | 3271 fps | 98.3% |
| Lovex S070 | <<locked>> | 80% | 42,844 psi | 67% | 3248 fps | 96.9% |
| Lovex S071 | <<locked>> | 88% | 35,317 psi | 55% | 3061 fps | 95.2% |
| Norma 204 | <<locked>> | 82% | 44,179 psi | 69% | 3310 fps | 95.1% |
| Norma MRP | 65.3 gr | 86% | 41,017 psi | 64% | 3320 fps | 96% |
| Norma URP | <<locked>> | 80% | 41,771 psi | 65% | 3271 fps | 98.6% |
| Ramshot Grand | <<locked>> | 90% | 48,805 psi | 76% | 3488 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 40,886 psi | 64% | 3255 fps | 97% |
| Ramshot Magnum | <<locked>> | 90% | 42,714 psi | 67% | 3310 fps | 96.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,949 psi | 44% | 2133 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 52,547 psi | 82% | 3448 fps | 99.1% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 49,922 psi | 78% | 3507 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 42,583 psi | 67% | 3301 fps | 98.6% |
| ReloadSwiss RS 70 | 62 gr | 80% | 41,002 psi | 64% | 3310 fps | 98.2% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 38,392 psi | 60% | 3274 fps | 95.2% |
| Rottweil R 903 | <<locked>> | 80% | 49,400 psi | 77% | 3386 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 48,254 psi | 76% | 3373 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 86% | 42,873 psi | 67% | 3301 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 45,701 psi | 72% | 3297 fps | 96.9% |
| Shooters World Long Rifle | <<locked>> | 80% | 44,628 psi | 70% | 3271 fps | 98.3% |
| Shooters World Precision | <<locked>> | 80% | 53,780 psi | 84% | 3448 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 42,844 psi | 67% | 3248 fps | 96.9% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 50,966 psi | 80% | 3451 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 49,879 psi | 78% | 3268 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 43,772 psi | 69% | 3205 fps | 97.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 45,469 psi | 71% | 3360 fps | 95.9% |
| Somchem S355 | <<locked>> | 80% | 49,414 psi | 77% | 3386 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 53,243 psi | 83% | 3422 fps | 95.8% |
| Somchem S365 | <<locked>> | 80% | 38,682 psi | 61% | 3222 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 40,553 psi | 64% | 3205 fps | 95.3% |
| Unknown powder | <<locked>> | 80% | 45,005 psi | 71% | 3343 fps | 98.8% |
| Vihtavuori N150 | <<locked>> | 80% | 42,453 psi | 67% | 3202 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 45,208 psi | 71% | 3310 fps | 99.2% |
| Vihtavuori N165 | <<locked>> | 90% | 41,611 psi | 65% | 3215 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 45,730 psi | 72% | 3356 fps | 99.2% |
| Vihtavuori N555 | <<locked>> | 80% | 33,765 psi | 53% | 3081 fps | 96.9% |
| Vihtavuori N560 | 69.8 gr | 94% | 51,459 psi | 81% | 3550 fps | 95.6% |
| Vihtavuori N565 | <<locked>> | 98% | 50,894 psi | 80% | 3504 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 42,612 psi | 67% | 3225 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 48,211 psi | 76% | 3425 fps | 98% |
| Winchester StaBALL HD | <<locked>> | 80% | 26,934 psi | 42% | 2949 fps | 95.8% |
| Winchester Supreme 780 | <<locked>> | 86% | 43,918 psi | 69% | 3278 fps | 95.3% |
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 79 powders for .257 Weath. Mag. loaded with the .257 | 87gr | Berger Target FB. Winchester StaBALL HD delivers the highest muzzle velocity at 3,737 fps; across all powders the maximum-charge window runs from 2,316 fps to 3,737 fps. ADI AR 2225 gives the best case fill at 100 %, and 79 of the 79 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 87.0 gr projectile in 0.257" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. ADI AR 2225, Alliant Reloder-25, Bofors RP15 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. Vihtavuori N560, Norma MRP, ReloadSwiss RS 70 rank at the top here: for .257 Weath. Mag. with the .257 | 87gr | Berger Target FB 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.