Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 85gr | Nosler CT Ballistic Silvertip bullet and 81 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate High Country, Norma MRP and Alliant Reloder-16.
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 2700 | <<locked>> | 82% | 57,435 psi | 90% | 3524 fps | 98.7% |
| Accurate 3100 | <<locked>> | 96% | 53,882 psi | 84% | 3507 fps | 99.4% |
| Accurate 4064 | <<locked>> | 82% | 57,072 psi | 89% | 3514 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 55,013 psi | 86% | 3570 fps | 100% |
| Accurate High Country | <<locked>> | 94% | 55,201 psi | 87% | 3668 fps | 97% |
| ADI AR 2208 | <<locked>> | 84% | 56,434 psi | 88% | 3547 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 56,173 psi | 88% | 3622 fps | 98% |
| ADI AR 2213 | <<locked>> | 96% | 54,099 psi | 85% | 3609 fps | 96.4% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 56,478 psi | 89% | 3615 fps | 98% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 56,478 psi | 89% | 3615 fps | 98% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 57,682 psi | 90% | 3576 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 55,854 psi | 88% | 3645 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 57,261 psi | 90% | 3665 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 55,753 psi | 87% | 3606 fps | 98% |
| Alliant Reloder-22 | <<locked>> | 98% | 57,450 psi | 90% | 3675 fps | 98.4% |
| Alliant Reloder-23 | <<locked>> | 98% | 54,491 psi | 85% | 3593 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 50,502 psi | 79% | 3570 fps | 99.7% |
| Alliant Reloder-26 | <<locked>> | 94% | 55,245 psi | 87% | 3688 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 56,289 psi | 88% | 3652 fps | 98.1% |
| Bofors RP3 | <<locked>> | 82% | 55,172 psi | 86% | 3530 fps | 100% |
| Bofors RP5 | <<locked>> | 98% | 57,450 psi | 90% | 3675 fps | 98.4% |
| Bofors RP7 | <<locked>> | 86% | 54,360 psi | 85% | 3510 fps | 98.4% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 49,864 psi | 78% | 3497 fps | 96.3% |
| Hodgdon H380 | <<locked>> | 82% | 55,477 psi | 87% | 3550 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 88% | 57,101 psi | 89% | 3632 fps | 99.2% |
| Hodgdon H4350 | <<locked>> | 86% | 56,318 psi | 88% | 3586 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 96% | 56,797 psi | 89% | 3589 fps | 96.3% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 56,101 psi | 88% | 3550 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 49,458 psi | 78% | 3619 fps | 97.7% |
| Hodgdon Superformance | <<locked>> | 86% | 53,766 psi | 84% | 3589 fps | 98.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,550 psi | 57% | 2339 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 55,782 psi | 87% | 3527 fps | 100% |
| IMR 4350 | <<locked>> | 90% | 55,912 psi | 88% | 3547 fps | 98.7% |
| IMR 4451 Enduron | <<locked>> | 86% | 55,883 psi | 88% | 3540 fps | 99% |
| IMR 4831 | <<locked>> | 90% | 55,448 psi | 87% | 3560 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 55,317 psi | 87% | 3530 fps | 96.2% |
| IMR 7828 SSC | <<locked>> | 98% | 55,521 psi | 87% | 3648 fps | 96.9% |
| Lovex S062 | <<locked>> | 82% | 56,362 psi | 88% | 3524 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 56,362 psi | 88% | 3540 fps | 99.7% |
| Lovex S070 | <<locked>> | 88% | 54,462 psi | 85% | 3527 fps | 99% |
| Lovex S071ᴾ | <<locked>> | 100% | 51,343 psi | 80% | 3461 fps | 99.1% |
| Norma 203B | <<locked>> | 82% | 57,232 psi | 90% | 3586 fps | 100% |
| Norma 204 | <<locked>> | 90% | 57,101 psi | 89% | 3609 fps | 98% |
| Norma MRP | <<locked>> | 96% | 57,421 psi | 90% | 3704 fps | 99.3% |
| Norma URP | <<locked>> | 90% | 57,392 psi | 90% | 3619 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 56,130 psi | 88% | 3665 fps | 97.4% |
| Ramshot Hunter | <<locked>> | 90% | 56,347 psi | 88% | 3612 fps | 99.6% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 54,665 psi | 86% | 3586 fps | 98.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,318 psi | 58% | 2392 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 55,274 psi | 87% | 3527 fps | 99.3% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 56,623 psi | 89% | 3658 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 55,317 psi | 87% | 3593 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 57,624 psi | 90% | 3694 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 50,314 psi | 79% | 3619 fps | 98.9% |
| Rottweil R 903 | <<locked>> | 84% | 55,506 psi | 87% | 3530 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 57,566 psi | 90% | 3586 fps | 97.2% |
| Rottweil R 905 | <<locked>> | 94% | 55,143 psi | 86% | 3593 fps | 98% |
| Rottweil R 907 | <<locked>> | 86% | 54,360 psi | 85% | 3510 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 88% | 56,362 psi | 88% | 3540 fps | 99.7% |
| Shooters World Precision | <<locked>> | 82% | 56,362 psi | 88% | 3524 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 54,462 psi | 85% | 3527 fps | 99% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 57,101 psi | 89% | 3596 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 55,608 psi | 87% | 3396 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 56,130 psi | 88% | 3481 fps | 99.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 54,679 psi | 86% | 3586 fps | 97.9% |
| Somchem S355 | <<locked>> | 84% | 55,187 psi | 86% | 3524 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 56,014 psi | 88% | 3504 fps | 96.2% |
| Somchem S365 | <<locked>> | 92% | 57,595 psi | 90% | 3622 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 55,724 psi | 87% | 3556 fps | 98.7% |
| Vihtavuori N150 | <<locked>> | 86% | 56,594 psi | 89% | 3491 fps | 100% |
| Vihtavuori N160 | <<locked>> | 88% | 55,492 psi | 87% | 3547 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 55,390 psi | 87% | 3530 fps | 98.4% |
| Vihtavuori N540 | <<locked>> | 82% | 57,319 psi | 90% | 3494 fps | 100% |
| Vihtavuori N550 | <<locked>> | 88% | 54,853 psi | 86% | 3547 fps | 99.9% |
| Vihtavuori N555 | <<locked>> | 96% | 56,971 psi | 89% | 3629 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 57,290 psi | 90% | 3691 fps | 96.8% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 53,243 psi | 83% | 3576 fps | 96.2% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 55,579 psi | 87% | 3497 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 57,377 psi | 90% | 3635 fps | 99.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 55,811 psi | 87% | 3743 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 55,927 psi | 88% | 3550 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% | 53,447 psi | 84% | 3451 fps | 98.1% |
| Accurate 3100 | <<locked>> | 86% | 38,029 psi | 60% | 3163 fps | 96% |
| Accurate 4064 | <<locked>> | 80% | 53,519 psi | 84% | 3455 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 41,466 psi | 65% | 3287 fps | 98.4% |
| Accurate High Country | 68 gr | 90% | 47,805 psi | 75% | 3514 fps | 95% |
| ADI AR 2208 | <<locked>> | 80% | 49,777 psi | 78% | 3422 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 88% | 45,847 psi | 72% | 3406 fps | 95.5% |
| ADI AR 2213 | <<locked>> | 94% | 50,386 psi | 79% | 3530 fps | 95.4% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 46,079 psi | 72% | 3402 fps | 95.6% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 46,079 psi | 72% | 3402 fps | 95.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 50,821 psi | 80% | 3451 fps | 100% |
| Alliant Reloder-16 | 56.4 gr | 80% | 39,813 psi | 62% | 3297 fps | 98.4% |
| Alliant Reloder-17 | <<locked>> | 80% | 46,079 psi | 72% | 3455 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 45,571 psi | 71% | 3392 fps | 95.5% |
| Alliant Reloder-22 | <<locked>> | 90% | 43,613 psi | 68% | 3383 fps | 95% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,559 psi | 46% | 2986 fps | 96.1% |
| Alliant Reloder-25 | <<locked>> | 90% | 36,071 psi | 57% | 3205 fps | 96% |
| Alliant Reloder-26 | <<locked>> | 82% | 34,577 psi | 54% | 3202 fps | 96.1% |
| Bofors RP15 | <<locked>> | 94% | 45,963 psi | 72% | 3435 fps | 95.6% |
| Bofors RP3 | <<locked>> | 80% | 51,706 psi | 81% | 3471 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 43,613 psi | 68% | 3383 fps | 95% |
| Bofors RP7 | <<locked>> | 80% | 44,962 psi | 70% | 3310 fps | 96.4% |
| Hodgdon H1000 | <<locked>> | 98% | 46,601 psi | 73% | 3425 fps | 95.3% |
| Hodgdon H380 | <<locked>> | 80% | 51,779 psi | 81% | 3481 fps | 99.6% |
| Hodgdon H414 | <<locked>> | 80% | 43,294 psi | 68% | 3340 fps | 96.5% |
| Hodgdon H4350 | <<locked>> | 80% | 46,122 psi | 72% | 3373 fps | 96% |
| Hodgdon H4831 SC | <<locked>> | 94% | 52,895 psi | 83% | 3514 fps | 95.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 37,391 psi | 59% | 3166 fps | 98.9% |
| Hodgdon Retumbo | <<locked>> | 96% | 43,163 psi | 68% | 3458 fps | 95.5% |
| Hodgdon Superformance | <<locked>> | 80% | 42,714 psi | 67% | 3350 fps | 96.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,267 psi | 43% | 2100 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 52,344 psi | 82% | 3465 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 40,408 psi | 63% | 3209 fps | 95% |
| IMR 4451 Enduron | <<locked>> | 80% | 46,180 psi | 72% | 3343 fps | 97.2% |
| IMR 4831 | <<locked>> | 80% | 39,784 psi | 62% | 3232 fps | 98.1% |
| IMR 4955 Enduron | <<locked>> | 92% | 51,967 psi | 81% | 3465 fps | 95.4% |
| IMR 7828 SSC | <<locked>> | 96% | 51,634 psi | 81% | 3566 fps | 95.9% |
| Lovex S062 | <<locked>> | 80% | 52,924 psi | 83% | 3461 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 43,859 psi | 69% | 3284 fps | 97.9% |
| Lovex S070 | <<locked>> | 80% | 42,090 psi | 66% | 3258 fps | 96.4% |
| Lovex S071 | <<locked>> | 90% | 36,753 psi | 58% | 3127 fps | 95.5% |
| Norma 203B | <<locked>> | 80% | 53,476 psi | 84% | 3520 fps | 100% |
| Norma 204 | <<locked>> | 84% | 46,282 psi | 73% | 3389 fps | 95.5% |
| Norma MRP | 65 gr | 86% | 39,943 psi | 63% | 3323 fps | 95.3% |
| Norma URP | <<locked>> | 80% | 40,959 psi | 64% | 3278 fps | 98.2% |
| Ramshot Grand | <<locked>> | 94% | 48,312 psi | 76% | 3504 fps | 95.4% |
| Ramshot Hunter | <<locked>> | 80% | 39,885 psi | 63% | 3255 fps | 96.4% |
| Ramshot Magnum | <<locked>> | 94% | 43,323 psi | 68% | 3346 fps | 95.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,818 psi | 44% | 2149 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 51,706 psi | 81% | 3461 fps | 98.9% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 48,907 psi | 77% | 3520 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 41,495 psi | 65% | 3304 fps | 98.2% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 40,001 psi | 63% | 3314 fps | 97.7% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 40,176 psi | 63% | 3353 fps | 95.6% |
| Rottweil R 903 | <<locked>> | 80% | 48,501 psi | 76% | 3399 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 50,633 psi | 79% | 3448 fps | 95.6% |
| Rottweil R 905 | <<locked>> | 88% | 44,730 psi | 70% | 3369 fps | 95.4% |
| Rottweil R 907 | <<locked>> | 80% | 44,962 psi | 70% | 3310 fps | 96.4% |
| Shooters World Long Rifle | <<locked>> | 80% | 43,859 psi | 69% | 3284 fps | 97.9% |
| Shooters World Precision | <<locked>> | 80% | 52,924 psi | 83% | 3461 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 42,090 psi | 66% | 3258 fps | 96.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 49,821 psi | 78% | 3461 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 49,081 psi | 77% | 3287 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 43,018 psi | 67% | 3215 fps | 96.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 44,338 psi | 69% | 3363 fps | 95.3% |
| Somchem S355 | <<locked>> | 80% | 48,573 psi | 76% | 3399 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 52,185 psi | 82% | 3428 fps | 95.3% |
| Somchem S365 | <<locked>> | 80% | 37,579 psi | 59% | 3225 fps | 99.7% |
| Somchem S385 | <<locked>> | 86% | 42,670 psi | 67% | 3284 fps | 95.8% |
| Vihtavuori N150 | <<locked>> | 80% | 46,427 psi | 73% | 3310 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 42,322 psi | 66% | 3278 fps | 98.5% |
| Vihtavuori N165 | <<locked>> | 90% | 42,163 psi | 66% | 3251 fps | 95.2% |
| Vihtavuori N540 | <<locked>> | 80% | 53,664 psi | 84% | 3432 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,959 psi | 66% | 3278 fps | 98.3% |
| Vihtavuori N555 | <<locked>> | 80% | 32,953 psi | 52% | 3084 fps | 96.3% |
| Vihtavuori N560 | <<locked>> | 94% | 53,374 psi | 84% | 3612 fps | 95.8% |
| Vihtavuori N565 | <<locked>> | 98% | 49,617 psi | 78% | 3504 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 41,640 psi | 65% | 3232 fps | 99.8% |
| Winchester 760 | <<locked>> | 80% | 43,468 psi | 68% | 3346 fps | 96.6% |
| Winchester StaBALL HD | <<locked>> | 82% | 28,108 psi | 44% | 3022 fps | 96.3% |
| Winchester Supreme 780 | <<locked>> | 90% | 45,252 psi | 71% | 3333 fps | 95.5% |
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 81 powders for .257 Weath. Mag. loaded with the .257 | 85gr | Nosler CT Ballistic Silvertip. Winchester StaBALL HD delivers the highest muzzle velocity at 3,743 fps; across all powders the maximum-charge window runs from 2,339 fps to 3,743 fps. Alliant Reloder-25 gives the best case fill at 100 %, and 81 of the 81 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 85.0 gr projectile in 0.257" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Alliant Reloder-25, Bofors RP15, Hodgdon H1000 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, Norma MRP, Alliant Reloder-16 rank at the top here: for .257 Weath. Mag. with the .257 | 85gr | Nosler CT Ballistic Silvertip 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.