Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 87gr | Frontier PH HPFB bullet and 79 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Norma MRP, Vihtavuori N560 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% | 56,231 psi | 88% | 3451 fps | 98.8% |
| Accurate 3100 | <<locked>> | 96% | 55,317 psi | 87% | 3504 fps | 99.7% |
| Accurate 4350 | <<locked>> | 88% | 56,507 psi | 89% | 3566 fps | 100% |
| ADI AR 2208 | <<locked>> | 84% | 57,682 psi | 90% | 3537 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 57,537 psi | 90% | 3619 fps | 98.4% |
| ADI AR 2213 | <<locked>> | 96% | 55,419 psi | 87% | 3609 fps | 97% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,220 psi | 65% | 3323 fps | 96.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 55,187 psi | 86% | 3501 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 57,029 psi | 89% | 3632 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 54,737 psi | 86% | 3586 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 57,087 psi | 89% | 3602 fps | 98.4% |
| Alliant Reloder-22 | <<locked>> | 96% | 55,187 psi | 86% | 3602 fps | 98.2% |
| Alliant Reloder-23 | <<locked>> | 98% | 55,999 psi | 88% | 3586 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 51,837 psi | 81% | 3566 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 94% | 56,913 psi | 89% | 3681 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 57,740 psi | 90% | 3645 fps | 98.5% |
| Bofors RP3 | <<locked>> | 82% | 56,507 psi | 89% | 3524 fps | 100% |
| Bofors RP5 | <<locked>> | 96% | 55,187 psi | 86% | 3602 fps | 98.2% |
| Bofors RP7 | <<locked>> | 86% | 55,593 psi | 87% | 3504 fps | 98.8% |
| Hodgdon H380 | <<locked>> | 82% | 56,521 psi | 89% | 3540 fps | 100% |
| Hodgdon H414 | <<locked>> | 84% | 55,651 psi | 87% | 3573 fps | 99.2% |
| Hodgdon H4350 | <<locked>> | 88% | 55,811 psi | 87% | 3547 fps | 98.4% |
| Hodgdon H4831 | <<locked>> | 98% | 54,433 psi | 85% | 3520 fps | 96.1% |
| Hodgdon H4831 SC | <<locked>> | 94% | 54,172 psi | 85% | 3514 fps | 96% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 57,537 psi | 90% | 3537 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 50,763 psi | 80% | 3622 fps | 98.3% |
| Hodgdon Superformance | <<locked>> | 86% | 55,143 psi | 86% | 3586 fps | 99% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,579 psi | 57% | 2316 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 57,087 psi | 89% | 3527 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,507 psi | 89% | 3510 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 55,114 psi | 86% | 3481 fps | 99.1% |
| IMR 4350 | <<locked>> | 90% | 57,130 psi | 90% | 3540 fps | 99.1% |
| IMR 4451 Enduron | <<locked>> | 86% | 57,072 psi | 89% | 3533 fps | 99.3% |
| IMR 4831 | <<locked>> | 92% | 54,505 psi | 85% | 3514 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 56,492 psi | 89% | 3527 fps | 96.8% |
| IMR 7828 SSC | <<locked>> | 96% | 57,145 psi | 90% | 3652 fps | 97.5% |
| Lovex S062 | <<locked>> | 82% | 57,377 psi | 90% | 3507 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 57,566 psi | 90% | 3533 fps | 99.9% |
| Lovex S070 | <<locked>> | 88% | 55,724 psi | 87% | 3517 fps | 99.3% |
| Lovex S071ᴾ | <<locked>> | 100% | 52,707 psi | 83% | 3455 fps | 99.4% |
| Norma 204 | <<locked>> | 88% | 54,549 psi | 85% | 3533 fps | 97.8% |
| Norma MRP | <<locked>> | 94% | 54,868 psi | 86% | 3629 fps | 99.2% |
| Norma URP | <<locked>> | 88% | 54,882 psi | 86% | 3543 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 57,348 psi | 90% | 3661 fps | 97.9% |
| Ramshot Hunter | <<locked>> | 90% | 57,725 psi | 90% | 3606 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 96% | 54,201 psi | 85% | 3553 fps | 98.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,362 psi | 59% | 2369 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 56,246 psi | 88% | 3517 fps | 99.5% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 53,867 psi | 84% | 3576 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 56,492 psi | 89% | 3583 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 55,056 psi | 86% | 3615 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 51,880 psi | 81% | 3622 fps | 99.3% |
| Rottweil R 903 | <<locked>> | 84% | 56,608 psi | 89% | 3517 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 54,969 psi | 86% | 3507 fps | 96.9% |
| Rottweil R 905 | <<locked>> | 94% | 56,260 psi | 88% | 3579 fps | 98.4% |
| Rottweil R 907 | <<locked>> | 86% | 55,593 psi | 87% | 3504 fps | 98.8% |
| Shooters World Long Rifle | <<locked>> | 88% | 57,566 psi | 90% | 3533 fps | 99.9% |
| Shooters World Precision | <<locked>> | 82% | 57,377 psi | 90% | 3507 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 55,724 psi | 87% | 3517 fps | 99.3% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 54,636 psi | 86% | 3520 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 56,521 psi | 89% | 3379 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 57,087 psi | 89% | 3471 fps | 99.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 55,811 psi | 87% | 3576 fps | 98.3% |
| Somchem S355 | <<locked>> | 84% | 56,202 psi | 88% | 3510 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 57,217 psi | 90% | 3497 fps | 96.7% |
| Somchem S365 | <<locked>> | 90% | 55,071 psi | 86% | 3547 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 57,072 psi | 89% | 3553 fps | 99.1% |
| Unknown powder | <<locked>> | 86% | 55,027 psi | 86% | 3547 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 88% | 54,839 psi | 86% | 3438 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 55,492 psi | 87% | 3507 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 54,665 psi | 86% | 3488 fps | 98.5% |
| Vihtavuori N550 | <<locked>> | 86% | 56,144 psi | 88% | 3566 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 54,592 psi | 86% | 3553 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 55,317 psi | 87% | 3625 fps | 96.6% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 54,723 psi | 86% | 3579 fps | 96.8% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 56,884 psi | 89% | 3488 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 55,651 psi | 87% | 3573 fps | 99.2% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 57,725 psi | 90% | 3737 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 54,868 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% | 49,226 psi | 77% | 3320 fps | 97.6% |
| Accurate 3100 | <<locked>> | 84% | 36,434 psi | 57% | 3091 fps | 95.6% |
| Accurate 4350 | <<locked>> | 80% | 42,685 psi | 67% | 3287 fps | 98.9% |
| ADI AR 2208 | <<locked>> | 80% | 50,676 psi | 79% | 3409 fps | 99.9% |
| ADI AR 2209 | <<locked>> | 86% | 43,801 psi | 69% | 3327 fps | 95.1% |
| ADI AR 2213 | <<locked>> | 92% | 48,080 psi | 75% | 3451 fps | 95% |
| ADI AR 2225 | <<locked>> | 98% | 38,653 psi | 61% | 3248 fps | 95.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 51,793 psi | 81% | 3442 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 40,698 psi | 64% | 3294 fps | 98.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 47,195 psi | 74% | 3445 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 43,627 psi | 68% | 3317 fps | 95.2% |
| Alliant Reloder-22 | <<locked>> | 90% | 44,831 psi | 70% | 3383 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 30,313 psi | 48% | 2986 fps | 96.9% |
| Alliant Reloder-25 | <<locked>> | 88% | 34,592 psi | 54% | 3136 fps | 95.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 32,996 psi | 52% | 3123 fps | 95.6% |
| Bofors RP15 | <<locked>> | 92% | 44,251 psi | 69% | 3366 fps | 95.4% |
| Bofors RP3 | <<locked>> | 80% | 52,736 psi | 83% | 3455 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 44,831 psi | 70% | 3383 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 45,788 psi | 72% | 3304 fps | 96.9% |
| Hodgdon H380 | <<locked>> | 80% | 52,779 psi | 83% | 3468 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 80% | 48,312 psi | 76% | 3428 fps | 98% |
| Hodgdon H4350 | <<locked>> | 80% | 43,120 psi | 68% | 3274 fps | 95.3% |
| Hodgdon H4831 | <<locked>> | 96% | 50,952 psi | 80% | 3451 fps | 95.2% |
| Hodgdon H4831 SC | <<locked>> | 92% | 50,488 psi | 79% | 3438 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 38,493 psi | 60% | 3163 fps | 99.3% |
| Hodgdon Retumbo | <<locked>> | 94% | 41,365 psi | 65% | 3379 fps | 95.1% |
| Hodgdon Superformance | <<locked>> | 80% | 43,932 psi | 69% | 3350 fps | 96.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,325 psi | 43% | 2080 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,606 psi | 84% | 3468 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,777 psi | 78% | 3386 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 80% | 48,689 psi | 76% | 3350 fps | 98.1% |
| IMR 4350 | <<locked>> | 80% | 41,220 psi | 65% | 3205 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 80% | 47,210 psi | 74% | 3337 fps | 97.7% |
| IMR 4831 | <<locked>> | 80% | 36,825 psi | 58% | 3123 fps | 97.5% |
| IMR 4955 Enduron | <<locked>> | 90% | 49,676 psi | 78% | 3389 fps | 95.1% |
| IMR 7828 SSC | <<locked>> | 92% | 49,516 psi | 78% | 3497 fps | 95.6% |
| Lovex S062 | <<locked>> | 80% | 53,911 psi | 84% | 3448 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 44,686 psi | 70% | 3274 fps | 98.3% |
| Lovex S070 | <<locked>> | 80% | 42,946 psi | 67% | 3251 fps | 96.9% |
| Lovex S071 | <<locked>> | 88% | 35,360 psi | 55% | 3061 fps | 95.2% |
| Norma 204 | <<locked>> | 82% | 44,251 psi | 69% | 3314 fps | 95.1% |
| Norma MRP | 65.3 gr | 86% | 40,901 psi | 64% | 3317 fps | 96% |
| Norma URP | <<locked>> | 80% | 41,887 psi | 66% | 3271 fps | 98.6% |
| Ramshot Grand | <<locked>> | 90% | 48,921 psi | 77% | 3491 fps | 95.9% |
| Ramshot Hunter | <<locked>> | 80% | 40,973 psi | 64% | 3255 fps | 97% |
| Ramshot Magnum | <<locked>> | 90% | 42,830 psi | 67% | 3310 fps | 96.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,905 psi | 44% | 2129 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 52,649 psi | 83% | 3448 fps | 99.1% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 50,053 psi | 78% | 3510 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 42,496 psi | 67% | 3297 fps | 98.6% |
| ReloadSwiss RS 70 | 62.1 gr | 80% | 41,089 psi | 64% | 3314 fps | 98.2% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 38,479 psi | 60% | 3281 fps | 95.2% |
| Rottweil R 903 | <<locked>> | 80% | 49,530 psi | 78% | 3392 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 48,356 psi | 76% | 3373 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 86% | 42,786 psi | 67% | 3297 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 45,788 psi | 72% | 3304 fps | 96.9% |
| Shooters World Long Rifle | <<locked>> | 80% | 44,686 psi | 70% | 3274 fps | 98.3% |
| Shooters World Precision | <<locked>> | 80% | 53,911 psi | 84% | 3448 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 42,946 psi | 67% | 3251 fps | 96.9% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 51,082 psi | 80% | 3455 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 49,951 psi | 78% | 3271 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 43,859 psi | 69% | 3205 fps | 97.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 45,513 psi | 71% | 3363 fps | 95.9% |
| Somchem S355 | <<locked>> | 80% | 49,530 psi | 78% | 3389 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 53,316 psi | 84% | 3425 fps | 95.8% |
| Somchem S365 | <<locked>> | 80% | 38,609 psi | 61% | 3219 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 40,654 psi | 64% | 3205 fps | 95.3% |
| Unknown powder | <<locked>> | 80% | 45,092 psi | 71% | 3343 fps | 98.8% |
| Vihtavuori N150 | <<locked>> | 80% | 42,540 psi | 67% | 3202 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 45,266 psi | 71% | 3310 fps | 99.2% |
| Vihtavuori N165 | <<locked>> | 90% | 41,698 psi | 65% | 3215 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 45,788 psi | 72% | 3360 fps | 99.2% |
| Vihtavuori N555 | <<locked>> | 80% | 33,823 psi | 53% | 3081 fps | 96.9% |
| Vihtavuori N560 | 69.9 gr | 94% | 51,547 psi | 81% | 3553 fps | 95.7% |
| Vihtavuori N565 | <<locked>> | 98% | 50,981 psi | 80% | 3504 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 42,699 psi | 67% | 3228 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 48,312 psi | 76% | 3428 fps | 98% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,006 psi | 42% | 2953 fps | 95.9% |
| Winchester Supreme 780 | <<locked>> | 86% | 44,005 psi | 69% | 3278 fps | 95.4% |
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 87 powders for .257 Weath. Mag. loaded with the .257 | 87gr | Frontier PH HPFB. 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 2217 gives the best case fill at 100 %, and 87 of the 87 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 2217, ADI AR 2225, Alliant Reloder-25 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. Norma MRP, Vihtavuori N560, ReloadSwiss RS 70 rank at the top here: for .257 Weath. Mag. with the .257 | 87gr | Frontier PH HPFB they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2217, Baschieri & Pellagri 109, Norma 217 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.