Load Specifications
Load data in caliber .257 Weath. Mag. with .257 | 100gr | Reichenberg HDB Universal bullet and 76 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, Ramshot Grand and Winchester StaBALL HD.
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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Max Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2700 | <<locked>> | 82% | 56,405 psi | 88% | 3281 fps | 99.5% |
| Accurate 3100 | <<locked>> | 94% | 56,652 psi | 89% | 3346 fps | 100% |
| Accurate 4350 | <<locked>> | 86% | 57,464 psi | 90% | 3389 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 56,028 psi | 88% | 3445 fps | 96.8% |
| ADI AR 2209 | <<locked>> | 90% | 54,781 psi | 86% | 3386 fps | 98.9% |
| ADI AR 2213 | <<locked>> | 94% | 56,289 psi | 88% | 3448 fps | 98.4% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 50,691 psi | 79% | 3327 fps | 97.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 45,411 psi | 71% | 3278 fps | 99.2% |
| Alliant Reloder-16 | <<locked>> | 86% | 54,549 psi | 85% | 3392 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 55,608 psi | 87% | 3402 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 54,288 psi | 85% | 3369 fps | 98.9% |
| Alliant Reloder-22 | <<locked>> | 94% | 56,405 psi | 88% | 3445 fps | 99.3% |
| Alliant Reloder-23 | <<locked>> | 96% | 57,638 psi | 90% | 3415 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 57,276 psi | 90% | 3481 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 54,491 psi | 85% | 3451 fps | 100% |
| Bofors RP15 | <<locked>> | 96% | 55,579 psi | 87% | 3428 fps | 99.1% |
| Bofors RP30ᴾ | <<locked>> | 100% | 53,258 psi | 83% | 3409 fps | 98.4% |
| Bofors RP5 | <<locked>> | 94% | 56,405 psi | 88% | 3445 fps | 99.3% |
| Bofors RP7 | <<locked>> | 84% | 55,956 psi | 88% | 3327 fps | 99.6% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 52,069 psi | 82% | 3356 fps | 98.5% |
| Hodgdon H414 | <<locked>> | 82% | 56,478 psi | 89% | 3406 fps | 99.8% |
| Hodgdon H4350 | <<locked>> | 86% | 56,492 psi | 89% | 3376 fps | 99.3% |
| Hodgdon H4831 | <<locked>> | 96% | 55,680 psi | 87% | 3369 fps | 97.7% |
| Hodgdon H4831 SC | <<locked>> | 92% | 55,143 psi | 86% | 3363 fps | 97.6% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 54,926 psi | 86% | 3304 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 56,188 psi | 88% | 3560 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 84% | 56,202 psi | 88% | 3422 fps | 99.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,970 psi | 58% | 2178 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 56,942 psi | 89% | 3320 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 55,405 psi | 87% | 3304 fps | 99.7% |
| IMR 4350 | <<locked>> | 88% | 57,653 psi | 90% | 3369 fps | 99.7% |
| IMR 4451 Enduron | <<locked>> | 84% | 57,435 psi | 90% | 3356 fps | 99.8% |
| IMR 4831 | <<locked>> | 90% | 55,593 psi | 87% | 3343 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 57,087 psi | 89% | 3366 fps | 98.1% |
| IMR 7828 SSC | <<locked>> | 92% | 54,244 psi | 85% | 3422 fps | 98.1% |
| Lovex S065 | <<locked>> | 84% | 54,621 psi | 86% | 3294 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 56,405 psi | 88% | 3350 fps | 99.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 57,711 psi | 90% | 3363 fps | 100% |
| Norma 204 | <<locked>> | 86% | 55,056 psi | 86% | 3366 fps | 98.9% |
| Norma 217ᴾ | <<locked>> | 100% | 40,944 psi | 64% | 3189 fps | 97.5% |
| Norma MRP | <<locked>> | 92% | 56,376 psi | 88% | 3471 fps | 99.9% |
| Norma URP | <<locked>> | 86% | 55,883 psi | 88% | 3373 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 54,056 psi | 85% | 3428 fps | 98.4% |
| Ramshot Hunter | <<locked>> | 86% | 54,636 psi | 86% | 3366 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 94% | 55,666 psi | 87% | 3402 fps | 99.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,855 psi | 59% | 2228 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 57,725 psi | 90% | 3412 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 56,173 psi | 88% | 3445 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 57,566 psi | 90% | 3560 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 52,330 psi | 82% | 3419 fps | 97% |
| Rottweil R 903 | <<locked>> | 82% | 57,276 psi | 90% | 3333 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 55,811 psi | 87% | 3350 fps | 98.3% |
| Rottweil R 905 | <<locked>> | 92% | 57,348 psi | 90% | 3422 fps | 99.4% |
| Rottweil R 907 | <<locked>> | 84% | 55,956 psi | 88% | 3327 fps | 99.6% |
| Shooters World Long Rifle | <<locked>> | 84% | 54,621 psi | 86% | 3294 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 56,405 psi | 88% | 3350 fps | 99.9% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 56,956 psi | 89% | 3189 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 57,493 psi | 90% | 3301 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 56,913 psi | 89% | 3415 fps | 99.3% |
| Somchem S355 | <<locked>> | 82% | 56,942 psi | 89% | 3327 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 57,551 psi | 90% | 3333 fps | 98% |
| Somchem S365 | <<locked>> | 88% | 56,376 psi | 88% | 3373 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 54,288 psi | 85% | 3327 fps | 99.4% |
| Unknown powder | <<locked>> | 84% | 55,912 psi | 88% | 3369 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 55,274 psi | 87% | 3251 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 56,144 psi | 88% | 3333 fps | 100% |
| Vihtavuori N165 | <<locked>> | 96% | 55,811 psi | 87% | 3333 fps | 99.4% |
| Vihtavuori N550 | <<locked>> | 84% | 56,826 psi | 89% | 3389 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 56,260 psi | 88% | 3392 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 56,913 psi | 89% | 3478 fps | 98.1% |
| Vihtavuori N565 | <<locked>> | 98% | 56,333 psi | 88% | 3438 fps | 98.3% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 53,156 psi | 83% | 3422 fps | 96.5% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 57,319 psi | 90% | 3304 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 56,478 psi | 89% | 3406 fps | 99.8% |
| Winchester StaBALL HD | <<locked>> | 96% | 56,057 psi | 88% | 3507 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 55,666 psi | 87% | 3343 fps | 99.1% |
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% | 52,779 psi | 83% | 3219 fps | 99.2% |
| Accurate 3100 | <<locked>> | 80% | 34,896 psi | 55% | 2894 fps | 96.6% |
| Accurate 4350 | <<locked>> | 80% | 46,717 psi | 73% | 3196 fps | 99.9% |
| Accurate MAGPRO | <<locked>> | 92% | 52,228 psi | 82% | 3376 fps | 95.9% |
| ADI AR 2209 | <<locked>> | 80% | 38,885 psi | 61% | 3038 fps | 95% |
| ADI AR 2213 | <<locked>> | 88% | 45,847 psi | 72% | 3235 fps | 96% |
| ADI AR 2217 | <<locked>> | 96% | 44,266 psi | 69% | 3186 fps | 95.9% |
| ADI AR 2225 | <<locked>> | 92% | 34,766 psi | 54% | 2989 fps | 95.6% |
| Alliant Reloder-16 | <<locked>> | 80% | 44,570 psi | 70% | 3202 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 80% | 51,779 psi | 81% | 3337 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 38,928 psi | 61% | 3035 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 84% | 40,118 psi | 63% | 3104 fps | 95.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 33,518 psi | 53% | 2927 fps | 99.2% |
| Alliant Reloder-25 | <<locked>> | 82% | 31,140 psi | 49% | 2874 fps | 95.6% |
| Alliant Reloder-26 | 61.8 gr | 80% | 36,840 psi | 58% | 3077 fps | 98.5% |
| Bofors RP15 | <<locked>> | 86% | 39,798 psi | 62% | 3091 fps | 95.4% |
| Bofors RP30 | <<locked>> | 94% | 43,221 psi | 68% | 3199 fps | 96% |
| Bofors RP5 | <<locked>> | 84% | 40,118 psi | 63% | 3104 fps | 95.7% |
| Bofors RP7 | <<locked>> | 80% | 49,342 psi | 77% | 3202 fps | 98.8% |
| Hodgdon H1000 | <<locked>> | 94% | 42,322 psi | 66% | 3143 fps | 95.9% |
| Hodgdon H414 | <<locked>> | 80% | 52,489 psi | 82% | 3333 fps | 99.5% |
| Hodgdon H4350 | <<locked>> | 80% | 46,717 psi | 73% | 3182 fps | 97.7% |
| Hodgdon H4831 | <<locked>> | 90% | 45,658 psi | 72% | 3169 fps | 95.2% |
| Hodgdon H4831 SC | <<locked>> | 86% | 44,802 psi | 70% | 3150 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 42,032 psi | 66% | 3068 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 37,217 psi | 58% | 3107 fps | 95.1% |
| Hodgdon Superformance | <<locked>> | 80% | 48,312 psi | 76% | 3274 fps | 98.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,746 psi | 43% | 1955 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 53,417 psi | 84% | 3264 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 52,069 psi | 82% | 3241 fps | 99.4% |
| IMR 4350 | <<locked>> | 80% | 44,657 psi | 70% | 3117 fps | 97.9% |
| IMR 4451 Enduron | <<locked>> | 80% | 50,502 psi | 79% | 3228 fps | 99.2% |
| IMR 4831 | <<locked>> | 80% | 40,321 psi | 63% | 3041 fps | 99.3% |
| IMR 4955 Enduron | <<locked>> | 84% | 44,237 psi | 69% | 3107 fps | 95% |
| IMR 7828 SSC | <<locked>> | 86% | 43,903 psi | 69% | 3205 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 48,225 psi | 76% | 3176 fps | 99.6% |
| Lovex S070 | <<locked>> | 80% | 46,528 psi | 73% | 3159 fps | 98.8% |
| Lovex S071 | <<locked>> | 82% | 32,126 psi | 50% | 2812 fps | 95.4% |
| Norma 204 | <<locked>> | 80% | 44,846 psi | 70% | 3159 fps | 96.8% |
| Norma 217 | <<locked>> | 96% | 35,737 psi | 56% | 3048 fps | 95.4% |
| Norma MRP | <<locked>> | 80% | 36,492 psi | 57% | 3038 fps | 95.9% |
| Norma URP | <<locked>> | 80% | 45,774 psi | 72% | 3182 fps | 99.8% |
| Ramshot Grand | 65 gr | 84% | 42,989 psi | 67% | 3192 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 44,686 psi | 70% | 3173 fps | 99% |
| Ramshot Magnum | <<locked>> | 84% | 37,594 psi | 59% | 3025 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,398 psi | 45% | 2001 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 46,862 psi | 73% | 3219 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 45,049 psi | 71% | 3235 fps | 99.7% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 34,113 psi | 53% | 3002 fps | 95% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 48,283 psi | 76% | 3333 fps | 95.9% |
| Rottweil R 903 | <<locked>> | 80% | 53,708 psi | 84% | 3274 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 42,931 psi | 67% | 3087 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 80% | 38,290 psi | 60% | 3018 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 49,342 psi | 77% | 3202 fps | 98.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 48,225 psi | 76% | 3176 fps | 99.6% |
| Shooters World SW4350 | <<locked>> | 80% | 46,528 psi | 73% | 3159 fps | 98.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 53,432 psi | 84% | 3136 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 47,094 psi | 74% | 3110 fps | 98.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 40,611 psi | 64% | 3077 fps | 95.9% |
| Somchem S355 | <<locked>> | 80% | 53,447 psi | 84% | 3271 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 46,992 psi | 74% | 3136 fps | 95.7% |
| Somchem S365 | <<locked>> | 80% | 42,772 psi | 67% | 3130 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 38,827 psi | 61% | 2999 fps | 96.2% |
| Unknown powder | <<locked>> | 80% | 48,892 psi | 77% | 3241 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 80% | 45,963 psi | 72% | 3091 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 49,139 psi | 77% | 3209 fps | 100% |
| Vihtavuori N165 | <<locked>> | 84% | 37,318 psi | 58% | 2949 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 49,879 psi | 78% | 3261 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 37,579 psi | 59% | 3015 fps | 99.1% |
| Vihtavuori N560 | <<locked>> | 88% | 46,035 psi | 72% | 3261 fps | 95.6% |
| Vihtavuori N565 | <<locked>> | 92% | 45,614 psi | 71% | 3222 fps | 95.8% |
| Vihtavuori N568 | <<locked>> | 98% | 49,414 psi | 77% | 3346 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 46,499 psi | 73% | 3127 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 52,489 psi | 82% | 3333 fps | 99.5% |
| Winchester StaBALL HD | 59.4 gr | 80% | 29,863 psi | 47% | 2933 fps | 99.3% |
| Winchester Supreme 780 | <<locked>> | 80% | 38,696 psi | 61% | 2992 fps | 95.1% |
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 | 100gr | Reichenberg HDB Universal. Hodgdon Retumbo delivers the highest muzzle velocity at 3,560 fps; across all powders the maximum-charge window runs from 2,178 fps to 3,560 fps. ADI AR 2217 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 58–90 %, leaving at least 10 % headroom. The 100.0 gr projectile in 0.257" calls for a 1:11.0 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. Alliant Reloder-26, Ramshot Grand, Winchester StaBALL HD rank at the top here: for .257 Weath. Mag. with the .257 | 100gr | Reichenberg HDB Universal they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-33, IMR 7977 Enduron, IMR 8133 Enduron 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.