Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 80gr | Peregrine Plainsmaster (VLR-4) bullet and 85 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Norma MRP, Alliant Reloder-26 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 2495 | <<locked>> | 82% | 55,927 psi | 88% | 3533 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 57,740 psi | 90% | 3609 fps | 98.3% |
| Accurate 3100ᴾ | <<locked>> | 100% | 57,130 psi | 90% | 3645 fps | 99.4% |
| Accurate 4064 | <<locked>> | 84% | 56,521 psi | 89% | 3599 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 54,534 psi | 85% | 3648 fps | 99.8% |
| Accurate High Country | <<locked>> | 96% | 54,636 psi | 86% | 3737 fps | 96.2% |
| ADI AR 2208 | <<locked>> | 86% | 56,884 psi | 89% | 3642 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 56,275 psi | 88% | 3701 fps | 97.4% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 56,811 psi | 89% | 3783 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 56,231 psi | 88% | 3691 fps | 97.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 54,157 psi | 85% | 3602 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 54,404 psi | 85% | 3629 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 55,477 psi | 87% | 3727 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 57,290 psi | 90% | 3753 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 55,477 psi | 87% | 3678 fps | 97.4% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 57,145 psi | 90% | 3747 fps | 97.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 53,708 psi | 84% | 3665 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 46,557 psi | 73% | 3560 fps | 98.7% |
| Alliant Reloder-26 | <<locked>> | 96% | 54,389 psi | 85% | 3760 fps | 99.9% |
| Bofors RP15ᴾ | <<locked>> | 100% | 52,054 psi | 82% | 3648 fps | 96.7% |
| Bofors RP3 | <<locked>> | 84% | 54,911 psi | 86% | 3615 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 57,145 psi | 90% | 3747 fps | 97.9% |
| Bofors RP7 | <<locked>> | 88% | 54,563 psi | 86% | 3593 fps | 98% |
| Hodgdon H380 | <<locked>> | 84% | 55,463 psi | 87% | 3635 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 90% | 57,058 psi | 89% | 3714 fps | 98.9% |
| Hodgdon H4350 | <<locked>> | 88% | 56,492 psi | 89% | 3668 fps | 97.7% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 55,956 psi | 88% | 3632 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 56,971 psi | 89% | 3684 fps | 100% |
| Hodgdon Superformance | <<locked>> | 88% | 53,969 psi | 85% | 3675 fps | 98.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,216 psi | 57% | 2395 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 57,319 psi | 90% | 3652 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,115 psi | 88% | 3619 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 55,172 psi | 86% | 3589 fps | 98.5% |
| IMR 4350 | <<locked>> | 92% | 56,043 psi | 88% | 3632 fps | 98.3% |
| IMR 4451 Enduron | <<locked>> | 88% | 56,289 psi | 88% | 3629 fps | 98.6% |
| IMR 4831 | <<locked>> | 92% | 55,172 psi | 86% | 3638 fps | 99.9% |
| IMR 4895 | <<locked>> | 82% | 55,825 psi | 87% | 3665 fps | 100% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 55,158 psi | 86% | 3714 fps | 96.1% |
| Lovex S060 | <<locked>> | 82% | 57,377 psi | 90% | 3606 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 56,202 psi | 88% | 3612 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 56,391 psi | 88% | 3625 fps | 99.5% |
| Lovex S070 | <<locked>> | 90% | 54,360 psi | 85% | 3602 fps | 98.6% |
| Lovex S071ᴾ | <<locked>> | 100% | 46,934 psi | 74% | 3451 fps | 97.9% |
| Norma 201 | <<locked>> | 82% | 57,537 psi | 90% | 3632 fps | 100% |
| Norma 203B | <<locked>> | 84% | 57,290 psi | 90% | 3678 fps | 100% |
| Norma 204 | <<locked>> | 92% | 57,246 psi | 90% | 3691 fps | 97.5% |
| Norma MRP | <<locked>> | 98% | 56,927 psi | 89% | 3780 fps | 98.9% |
| Norma URP | <<locked>> | 92% | 57,043 psi | 89% | 3701 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 82% | 54,752 psi | 86% | 3635 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 55,956 psi | 88% | 3737 fps | 96.7% |
| Ramshot Hunter | <<locked>> | 92% | 56,202 psi | 88% | 3694 fps | 99.3% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 50,212 psi | 79% | 3576 fps | 97.3% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,680 psi | 57% | 2448 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 55,419 psi | 87% | 3612 fps | 99% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 56,608 psi | 89% | 3750 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 54,868 psi | 86% | 3668 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 57,725 psi | 90% | 3780 fps | 99.9% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 46,195 psi | 72% | 3586 fps | 97.2% |
| Rottweil R 902 | <<locked>> | 82% | 54,505 psi | 85% | 3566 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 55,274 psi | 87% | 3615 fps | 100% |
| Rottweil R 905 | <<locked>> | 96% | 54,679 psi | 86% | 3658 fps | 97.3% |
| Rottweil R 907 | <<locked>> | 88% | 54,563 psi | 86% | 3593 fps | 98% |
| Shooters World Long Rifle | <<locked>> | 90% | 56,391 psi | 88% | 3625 fps | 99.5% |
| Shooters World Precision | <<locked>> | 84% | 56,202 psi | 88% | 3612 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 54,360 psi | 85% | 3602 fps | 98.6% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 57,377 psi | 90% | 3684 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 56,057 psi | 88% | 3491 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 56,405 psi | 88% | 3566 fps | 98.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 54,215 psi | 85% | 3655 fps | 97.2% |
| Somchem S355 | <<locked>> | 86% | 55,129 psi | 86% | 3609 fps | 100% |
| Somchem S365 | <<locked>> | 94% | 56,855 psi | 89% | 3701 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 55,434 psi | 87% | 3629 fps | 98.2% |
| Vihtavuori N135 | <<locked>> | 82% | 54,868 psi | 86% | 3524 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 55,434 psi | 87% | 3537 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 56,739 psi | 89% | 3583 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 55,405 psi | 87% | 3629 fps | 99.8% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 54,955 psi | 86% | 3596 fps | 97.9% |
| Vihtavuori N540 | <<locked>> | 84% | 57,508 psi | 90% | 3586 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 54,679 psi | 86% | 3625 fps | 99.7% |
| Vihtavuori N555 | <<locked>> | 98% | 56,057 psi | 88% | 3701 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 56,971 psi | 89% | 3760 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 55,579 psi | 87% | 3583 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 57,276 psi | 90% | 3717 fps | 98.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 50,067 psi | 78% | 3734 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 55,927 psi | 88% | 3625 fps | 97.4% |
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 2495 | <<locked>> | 80% | 52,228 psi | 82% | 3474 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 50,314 psi | 79% | 3465 fps | 96.9% |
| Accurate 3100 | <<locked>> | 90% | 39,726 psi | 62% | 3278 fps | 95.9% |
| Accurate 4064 | <<locked>> | 80% | 49,516 psi | 78% | 3474 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 37,840 psi | 59% | 3274 fps | 96.8% |
| Accurate High Country | <<locked>> | 94% | 50,734 psi | 80% | 3658 fps | 95.2% |
| ADI AR 2208 | <<locked>> | 80% | 46,862 psi | 73% | 3445 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 92% | 48,892 psi | 77% | 3547 fps | 95.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 52,779 psi | 83% | 3707 fps | 99.9% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 49,211 psi | 77% | 3550 fps | 95.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,485 psi | 74% | 3474 fps | 99.9% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,734 psi | 80% | 3556 fps | 99.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,869 psi | 58% | 3294 fps | 96.9% |
| Alliant Reloder-17 | <<locked>> | 80% | 42,322 psi | 66% | 3451 fps | 99.5% |
| Alliant Reloder-19 | <<locked>> | 92% | 48,602 psi | 76% | 3537 fps | 95.7% |
| Alliant Reloder-22 | <<locked>> | 94% | 46,064 psi | 72% | 3517 fps | 95.1% |
| Alliant Reloder-23 | <<locked>> | 84% | 30,864 psi | 48% | 3100 fps | 96.1% |
| Alliant Reloder-25 | <<locked>> | 94% | 37,898 psi | 59% | 3330 fps | 96% |
| Alliant Reloder-26 | 66.6 gr | 86% | 36,608 psi | 57% | 3337 fps | 96.2% |
| Bofors RP15 | <<locked>> | 98% | 48,617 psi | 76% | 3570 fps | 95.7% |
| Bofors RP3 | <<locked>> | 80% | 47,761 psi | 75% | 3478 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 46,064 psi | 72% | 3517 fps | 95.1% |
| Bofors RP7 | <<locked>> | 82% | 44,846 psi | 70% | 3383 fps | 95.7% |
| Hodgdon H380 | <<locked>> | 80% | 48,370 psi | 76% | 3494 fps | 98.9% |
| Hodgdon H414 | <<locked>> | 82% | 43,091 psi | 68% | 3412 fps | 95.8% |
| Hodgdon H4350 | <<locked>> | 82% | 46,050 psi | 72% | 3448 fps | 95.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,272 psi | 54% | 3156 fps | 97.5% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 53,113 psi | 83% | 3615 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 42,641 psi | 67% | 3422 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,861 psi | 42% | 2152 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,505 psi | 84% | 3583 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,226 psi | 77% | 3488 fps | 99.7% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,764 psi | 81% | 3524 fps | 97.9% |
| IMR 4350 | <<locked>> | 84% | 43,091 psi | 68% | 3353 fps | 95.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,395 psi | 68% | 3353 fps | 95.7% |
| IMR 4831 | <<locked>> | 80% | 36,361 psi | 57% | 3215 fps | 96.5% |
| IMR 4895 | <<locked>> | 80% | 52,054 psi | 82% | 3596 fps | 100% |
| IMR 7828 SSC | <<locked>> | 98% | 51,474 psi | 81% | 3638 fps | 95.1% |
| Lovex S060 | <<locked>> | 80% | 53,882 psi | 84% | 3543 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,342 psi | 77% | 3484 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 40,857 psi | 64% | 3287 fps | 96.5% |
| Lovex S070 | <<locked>> | 82% | 41,698 psi | 65% | 3323 fps | 95.6% |
| Lovex S071 | <<locked>> | 94% | 38,174 psi | 60% | 3238 fps | 95.3% |
| Norma 201 | <<locked>> | 80% | 53,925 psi | 85% | 3570 fps | 100% |
| Norma 203B | <<locked>> | 80% | 50,067 psi | 78% | 3540 fps | 99.9% |
| Norma 204 | <<locked>> | 88% | 49,574 psi | 78% | 3537 fps | 95.7% |
| Norma MRP | 67.6 gr | 90% | 42,206 psi | 66% | 3458 fps | 95.4% |
| Norma URP | <<locked>> | 80% | 37,753 psi | 59% | 3274 fps | 96.7% |
| Ramshot Big Game | <<locked>> | 80% | 51,024 psi | 80% | 3563 fps | 99.9% |
| Ramshot Grand | <<locked>> | 98% | 51,764 psi | 81% | 3652 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 82% | 39,566 psi | 62% | 3323 fps | 95.6% |
| Ramshot Magnum | <<locked>> | 96% | 43,018 psi | 67% | 3409 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,340 psi | 43% | 2205 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 48,312 psi | 76% | 3468 fps | 97.8% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 45,034 psi | 71% | 3530 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 38,014 psi | 60% | 3294 fps | 96.6% |
| ReloadSwiss RS 70 | 61.4 gr | 80% | 36,956 psi | 58% | 3301 fps | 95.8% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 42,728 psi | 67% | 3491 fps | 95.9% |
| Rottweil R 902 | <<locked>> | 80% | 51,053 psi | 80% | 3504 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 44,933 psi | 70% | 3412 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 92% | 47,427 psi | 74% | 3507 fps | 95.5% |
| Rottweil R 907 | <<locked>> | 82% | 44,846 psi | 70% | 3383 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,857 psi | 64% | 3287 fps | 96.5% |
| Shooters World Precision | <<locked>> | 80% | 49,342 psi | 77% | 3484 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 41,698 psi | 65% | 3323 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 46,499 psi | 73% | 3478 fps | 99.6% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,151 psi | 72% | 3320 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 42,844 psi | 67% | 3287 fps | 95.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 47,007 psi | 74% | 3504 fps | 95.4% |
| Somchem S355 | <<locked>> | 80% | 45,252 psi | 71% | 3415 fps | 99.7% |
| Somchem S365 | <<locked>> | 80% | 34,156 psi | 54% | 3212 fps | 98.7% |
| Somchem S385 | <<locked>> | 90% | 44,976 psi | 70% | 3412 fps | 95.8% |
| Vihtavuori N135 | <<locked>> | 80% | 51,532 psi | 81% | 3468 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 51,982 psi | 81% | 3481 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,250 psi | 68% | 3327 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 80% | 39,146 psi | 61% | 3278 fps | 97.2% |
| Vihtavuori N165 | <<locked>> | 94% | 44,599 psi | 70% | 3386 fps | 95.3% |
| Vihtavuori N540 | <<locked>> | 80% | 50,444 psi | 79% | 3465 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,798 psi | 61% | 3274 fps | 96.9% |
| Vihtavuori N555 | <<locked>> | 82% | 31,865 psi | 50% | 3127 fps | 95.1% |
| Vihtavuori N560 | <<locked>> | 96% | 52,953 psi | 83% | 3681 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,682 psi | 61% | 3238 fps | 99.1% |
| Winchester 760 | <<locked>> | 82% | 43,323 psi | 68% | 3419 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 86% | 29,428 psi | 46% | 3140 fps | 96.3% |
| Winchester Supreme 780 | <<locked>> | 94% | 48,153 psi | 75% | 3471 fps | 95.6% |
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 85 powders for .257 Weath. Mag. loaded with the .257 | 80gr | Peregrine Plainsmaster (VLR-4). Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,783 fps; across all powders the maximum-charge window runs from 2,395 fps to 3,783 fps. Accurate 3100 gives the best case fill at 100 %, and 85 of the 85 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 80.0 gr projectile in 0.257" calls for a 1:9.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-22, Alliant Reloder-23 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, Alliant Reloder-26, ReloadSwiss RS 70 rank at the top here: for .257 Weath. Mag. with the .257 | 80gr | Peregrine Plainsmaster (VLR-4) 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.