Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 80gr | Barnes TTSX BT bullet and 85 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate High Country, Alliant Reloder-16 and Norma MRP.
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.
A valid access license is required to use the Personalized Load Calculator.
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% | 56,101 psi | 88% | 3537 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 54,056 psi | 85% | 3540 fps | 97.7% |
| Accurate 3100ᴾ | <<locked>> | 100% | 57,537 psi | 90% | 3648 fps | 99.5% |
| Accurate 4064 | <<locked>> | 84% | 56,724 psi | 89% | 3602 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 54,694 psi | 86% | 3652 fps | 99.8% |
| Accurate High Country | <<locked>> | 96% | 55,085 psi | 86% | 3743 fps | 96.3% |
| ADI AR 2208 | <<locked>> | 86% | 57,058 psi | 89% | 3645 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 56,391 psi | 88% | 3701 fps | 97.5% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 57,058 psi | 89% | 3789 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 56,637 psi | 89% | 3698 fps | 97.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 54,331 psi | 85% | 3606 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 54,592 psi | 86% | 3632 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 55,666 psi | 87% | 3727 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 57,479 psi | 90% | 3757 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 55,854 psi | 88% | 3684 fps | 97.5% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 57,305 psi | 90% | 3750 fps | 97.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 54,143 psi | 85% | 3675 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 46,905 psi | 74% | 3570 fps | 98.8% |
| Alliant Reloder-26 | <<locked>> | 96% | 54,824 psi | 86% | 3766 fps | 99.9% |
| Bofors RP15ᴾ | <<locked>> | 100% | 52,431 psi | 82% | 3652 fps | 96.8% |
| Bofors RP3 | <<locked>> | 84% | 55,376 psi | 87% | 3622 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 57,305 psi | 90% | 3750 fps | 97.9% |
| Bofors RP7 | <<locked>> | 88% | 54,708 psi | 86% | 3596 fps | 98% |
| Hodgdon H380 | <<locked>> | 84% | 55,651 psi | 87% | 3638 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 90% | 57,203 psi | 90% | 3714 fps | 98.9% |
| Hodgdon H4350 | <<locked>> | 88% | 56,637 psi | 89% | 3668 fps | 97.8% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 56,159 psi | 88% | 3635 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 57,145 psi | 90% | 3688 fps | 100% |
| Hodgdon Superformance | <<locked>> | 88% | 54,143 psi | 85% | 3678 fps | 98.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,056 psi | 56% | 2395 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 57,508 psi | 90% | 3652 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,304 psi | 88% | 3625 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 55,347 psi | 87% | 3593 fps | 98.5% |
| IMR 4350 | <<locked>> | 92% | 56,217 psi | 88% | 3632 fps | 98.4% |
| IMR 4451 Enduron | <<locked>> | 88% | 56,434 psi | 88% | 3635 fps | 98.7% |
| IMR 4831 | <<locked>> | 92% | 55,317 psi | 87% | 3638 fps | 99.9% |
| IMR 4895 | <<locked>> | 82% | 56,028 psi | 88% | 3668 fps | 100% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 55,550 psi | 87% | 3724 fps | 96.2% |
| Lovex S060 | <<locked>> | 82% | 57,551 psi | 90% | 3612 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 56,391 psi | 88% | 3612 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 56,579 psi | 89% | 3625 fps | 99.5% |
| Lovex S070 | <<locked>> | 90% | 54,520 psi | 85% | 3606 fps | 98.6% |
| Lovex S071ᴾ | <<locked>> | 100% | 47,108 psi | 74% | 3451 fps | 98% |
| Norma 201 | <<locked>> | 82% | 57,740 psi | 90% | 3635 fps | 100% |
| Norma 203B | <<locked>> | 84% | 57,479 psi | 90% | 3681 fps | 100% |
| Norma 204 | <<locked>> | 92% | 57,363 psi | 90% | 3694 fps | 97.5% |
| Norma MRP | <<locked>> | 98% | 57,348 psi | 90% | 3786 fps | 99% |
| Norma URP | <<locked>> | 92% | 57,479 psi | 90% | 3707 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 54,911 psi | 86% | 3635 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 56,376 psi | 88% | 3747 fps | 96.8% |
| Ramshot Hunter | <<locked>> | 92% | 56,376 psi | 88% | 3698 fps | 99.3% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 50,589 psi | 79% | 3583 fps | 97.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,738 psi | 58% | 2448 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 55,593 psi | 87% | 3612 fps | 99% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 56,782 psi | 89% | 3753 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 55,056 psi | 86% | 3671 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 53,809 psi | 84% | 3707 fps | 99.7% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 46,514 psi | 73% | 3593 fps | 97.3% |
| Rottweil R 902 | <<locked>> | 82% | 54,708 psi | 86% | 3570 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 55,463 psi | 87% | 3615 fps | 100% |
| Rottweil R 905 | <<locked>> | 96% | 54,810 psi | 86% | 3661 fps | 97.4% |
| Rottweil R 907 | <<locked>> | 88% | 54,708 psi | 86% | 3596 fps | 98% |
| Shooters World Long Rifle | <<locked>> | 90% | 56,579 psi | 89% | 3625 fps | 99.5% |
| Shooters World Precision | <<locked>> | 84% | 56,391 psi | 88% | 3612 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 54,520 psi | 85% | 3606 fps | 98.6% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 57,566 psi | 90% | 3691 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 56,231 psi | 88% | 3494 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 56,492 psi | 89% | 3566 fps | 98.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 54,331 psi | 85% | 3658 fps | 97.3% |
| Somchem S355 | <<locked>> | 86% | 55,303 psi | 87% | 3615 fps | 100% |
| Somchem S365 | <<locked>> | 94% | 57,305 psi | 90% | 3704 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 55,579 psi | 87% | 3632 fps | 98.2% |
| Vihtavuori N135 | <<locked>> | 82% | 55,085 psi | 86% | 3527 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 55,622 psi | 87% | 3540 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 56,898 psi | 89% | 3583 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 55,608 psi | 87% | 3629 fps | 99.9% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 55,347 psi | 87% | 3606 fps | 97.9% |
| Vihtavuori N540 | <<locked>> | 84% | 57,711 psi | 90% | 3589 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 54,810 psi | 86% | 3629 fps | 99.8% |
| Vihtavuori N555 | <<locked>> | 98% | 56,217 psi | 88% | 3701 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 57,377 psi | 90% | 3770 fps | 96.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 55,970 psi | 88% | 3586 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 57,479 psi | 90% | 3717 fps | 98.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 50,299 psi | 79% | 3737 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 56,072 psi | 88% | 3625 fps | 97.5% |
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% | 52,214 psi | 82% | 3471 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 50,473 psi | 79% | 3468 fps | 97% |
| Accurate 3100 | <<locked>> | 90% | 39,900 psi | 63% | 3284 fps | 96% |
| Accurate 4064 | <<locked>> | 80% | 49,472 psi | 78% | 3474 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,014 psi | 60% | 3278 fps | 96.9% |
| Accurate High Country | 70.9 gr | 94% | 51,126 psi | 80% | 3661 fps | 95.3% |
| ADI AR 2208 | <<locked>> | 80% | 47,007 psi | 74% | 3448 fps | 99.4% |
| ADI AR 2209 | <<locked>> | 92% | 49,023 psi | 77% | 3550 fps | 95.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 53,011 psi | 83% | 3711 fps | 99.9% |
| Alliant Power Pro Varmint | <<locked>> | 92% | 49,356 psi | 77% | 3550 fps | 95.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,674 psi | 75% | 3478 fps | 99.9% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,923 psi | 80% | 3560 fps | 99.8% |
| Alliant Reloder-16 | 56.3 gr | 80% | 37,028 psi | 58% | 3297 fps | 97% |
| Alliant Reloder-17 | <<locked>> | 80% | 42,511 psi | 67% | 3458 fps | 99.6% |
| Alliant Reloder-19 | <<locked>> | 92% | 48,747 psi | 76% | 3540 fps | 95.8% |
| Alliant Reloder-22 | <<locked>> | 94% | 46,456 psi | 73% | 3524 fps | 95.3% |
| Alliant Reloder-23 | <<locked>> | 82% | 28,950 psi | 45% | 3035 fps | 95% |
| Alliant Reloder-25 | <<locked>> | 94% | 38,203 psi | 60% | 3337 fps | 96.1% |
| Alliant Reloder-26 | <<locked>> | 86% | 36,767 psi | 58% | 3340 fps | 96.3% |
| Bofors RP15 | <<locked>> | 98% | 48,747 psi | 76% | 3573 fps | 95.8% |
| Bofors RP3 | <<locked>> | 80% | 47,950 psi | 75% | 3481 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 46,456 psi | 73% | 3524 fps | 95.3% |
| Bofors RP7 | <<locked>> | 82% | 45,005 psi | 71% | 3386 fps | 95.7% |
| Hodgdon H380 | <<locked>> | 80% | 48,544 psi | 76% | 3497 fps | 98.9% |
| Hodgdon H414 | <<locked>> | 82% | 43,250 psi | 68% | 3419 fps | 95.9% |
| Hodgdon H4350 | <<locked>> | 82% | 46,209 psi | 72% | 3448 fps | 95.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,447 psi | 54% | 3163 fps | 97.6% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 53,287 psi | 84% | 3619 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 42,786 psi | 67% | 3428 fps | 95.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,948 psi | 42% | 2156 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,693 psi | 84% | 3586 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,414 psi | 77% | 3491 fps | 99.7% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,938 psi | 81% | 3527 fps | 98% |
| IMR 4350 | <<locked>> | 84% | 43,279 psi | 68% | 3360 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,555 psi | 68% | 3356 fps | 95.8% |
| IMR 4831 | <<locked>> | 80% | 36,492 psi | 57% | 3219 fps | 96.5% |
| IMR 4895 | <<locked>> | 80% | 52,257 psi | 82% | 3599 fps | 100% |
| IMR 7828 SSC | <<locked>> | 98% | 51,590 psi | 81% | 3638 fps | 95.1% |
| Lovex S060 | <<locked>> | 80% | 54,027 psi | 85% | 3547 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,545 psi | 78% | 3488 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 40,799 psi | 64% | 3284 fps | 96.5% |
| Lovex S070 | <<locked>> | 82% | 41,858 psi | 66% | 3327 fps | 95.7% |
| Lovex S071 | <<locked>> | 94% | 38,319 psi | 60% | 3245 fps | 95.4% |
| Norma 201 | <<locked>> | 80% | 53,853 psi | 84% | 3566 fps | 100% |
| Norma 203B | <<locked>> | 80% | 50,256 psi | 79% | 3543 fps | 99.9% |
| Norma 204 | <<locked>> | 88% | 49,951 psi | 78% | 3543 fps | 95.8% |
| Norma MRP | 67.9 gr | 90% | 42,554 psi | 67% | 3465 fps | 95.6% |
| Norma URP | <<locked>> | 80% | 37,927 psi | 59% | 3278 fps | 96.8% |
| Ramshot Big Game | <<locked>> | 80% | 51,198 psi | 80% | 3566 fps | 99.9% |
| Ramshot Grand | <<locked>> | 98% | 52,141 psi | 82% | 3661 fps | 95.7% |
| Ramshot Hunter | <<locked>> | 82% | 39,726 psi | 62% | 3330 fps | 95.7% |
| Ramshot Magnum | <<locked>> | 96% | 43,105 psi | 68% | 3412 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,427 psi | 43% | 2208 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 48,472 psi | 76% | 3471 fps | 97.8% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 45,208 psi | 71% | 3533 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 38,189 psi | 60% | 3297 fps | 96.7% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 37,086 psi | 58% | 3301 fps | 95.9% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 43,018 psi | 67% | 3497 fps | 96% |
| Rottweil R 902 | <<locked>> | 80% | 51,256 psi | 80% | 3507 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 45,136 psi | 71% | 3415 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 92% | 47,805 psi | 75% | 3517 fps | 95.7% |
| Rottweil R 907 | <<locked>> | 82% | 45,005 psi | 71% | 3386 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,799 psi | 64% | 3284 fps | 96.5% |
| Shooters World Precision | <<locked>> | 80% | 49,545 psi | 78% | 3488 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 41,858 psi | 66% | 3327 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 46,673 psi | 73% | 3481 fps | 99.6% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,354 psi | 73% | 3323 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 43,004 psi | 67% | 3291 fps | 95.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 47,384 psi | 74% | 3510 fps | 95.5% |
| Somchem S355 | <<locked>> | 80% | 45,237 psi | 71% | 3415 fps | 99.7% |
| Somchem S365 | <<locked>> | 80% | 34,330 psi | 54% | 3215 fps | 98.8% |
| Somchem S385 | <<locked>> | 90% | 45,107 psi | 71% | 3415 fps | 95.8% |
| Vihtavuori N135 | <<locked>> | 80% | 51,764 psi | 81% | 3471 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 52,156 psi | 82% | 3484 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,424 psi | 68% | 3330 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 80% | 39,320 psi | 62% | 3281 fps | 97.2% |
| Vihtavuori N165 | <<locked>> | 94% | 44,759 psi | 70% | 3386 fps | 95.4% |
| Vihtavuori N540 | <<locked>> | 80% | 50,604 psi | 79% | 3468 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,957 psi | 61% | 3278 fps | 96.9% |
| Vihtavuori N555 | <<locked>> | 82% | 32,039 psi | 50% | 3130 fps | 95.2% |
| Vihtavuori N560 | <<locked>> | 96% | 53,345 psi | 84% | 3691 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,827 psi | 61% | 3241 fps | 99.2% |
| Winchester 760 | <<locked>> | 82% | 43,482 psi | 68% | 3422 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 86% | 29,530 psi | 46% | 3143 fps | 96.4% |
| Winchester Supreme 780 | <<locked>> | 94% | 48,515 psi | 76% | 3478 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 85 powders for .257 Weath. Mag. loaded with the .257 | 80gr | Barnes TTSX BT. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,789 fps; across all powders the maximum-charge window runs from 2,395 fps to 3,789 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 56–90 %, leaving at least 10 % headroom. The 80.0 gr projectile in 0.257" calls for a 1:10.5 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. Accurate High Country, Alliant Reloder-16, Norma MRP rank at the top here: for .257 Weath. Mag. with the .257 | 80gr | Barnes TTSX BT 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.