Load Specifications
Load data in caliber .257 Roberts with .257 | 90gr | Prvi Partizan HP bullet and 58 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 60, Alliant Reloder-17 and SNPE Vectan SP 11.
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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 84% | 44,295 psi | 86% | 3002 fps | 100% |
| Accurate 4064 | <<locked>> | 86% | 44,657 psi | 87% | 3048 fps | 100% |
| Accurate 4350 | <<locked>> | 94% | 43,497 psi | 84% | 3081 fps | 96.3% |
| ADI AR 2206H | <<locked>> | 82% | 45,223 psi | 88% | 3061 fps | 97.9% |
| ADI AR 2208 | <<locked>> | 88% | 46,412 psi | 90% | 3064 fps | 97.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 44,295 psi | 86% | 3150 fps | 96.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 46,166 psi | 90% | 3091 fps | 98.9% |
| Alliant Reloder-15 | <<locked>> | 86% | 46,572 psi | 90% | 3107 fps | 97.8% |
| Alliant Reloder-16 | <<locked>> | 96% | 45,905 psi | 89% | 3159 fps | 97.2% |
| Alliant Reloder-17 | <<locked>> | 92% | 46,122 psi | 90% | 3189 fps | 98.7% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 44,715 psi | 87% | 3061 fps | 96.8% |
| Bofors RP3 | <<locked>> | 88% | 45,992 psi | 89% | 3097 fps | 98.9% |
| Hodgdon BL-C2 | <<locked>> | 82% | 46,224 psi | 90% | 3094 fps | 99.4% |
| Hodgdon H380 | <<locked>> | 86% | 44,135 psi | 86% | 3038 fps | 95.8% |
| Hodgdon H4895 | <<locked>> | 82% | 45,600 psi | 89% | 3074 fps | 98.5% |
| Hodgdon Hybrid 100V | <<locked>> | 98% | 45,020 psi | 87% | 3087 fps | 98.4% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 44,411 psi | 86% | 3097 fps | 98.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,215 psi | 68% | 2024 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 43,918 psi | 85% | 3022 fps | 98.1% |
| IMR 3031 | <<locked>> | 82% | 45,179 psi | 88% | 3081 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 45,977 psi | 89% | 3048 fps | 97.7% |
| IMR 4831 | <<locked>> | 96% | 44,628 psi | 87% | 3084 fps | 96.7% |
| IMR 4895 | <<locked>> | 84% | 44,628 psi | 87% | 3081 fps | 97.9% |
| Lovex D073.6 | <<locked>> | 82% | 44,527 psi | 86% | 3045 fps | 99.7% |
| Lovex S060 | <<locked>> | 82% | 45,585 psi | 89% | 2999 fps | 98.1% |
| Lovex S062 | <<locked>> | 86% | 45,818 psi | 89% | 3054 fps | 99.1% |
| Norma 201 | <<locked>> | 82% | 44,469 psi | 86% | 3015 fps | 98.8% |
| Norma 202 | <<locked>> | 82% | 44,686 psi | 87% | 3025 fps | 99.9% |
| Norma 203B | <<locked>> | 86% | 45,818 psi | 89% | 3091 fps | 98.1% |
| Norma URP | <<locked>> | 96% | 46,485 psi | 90% | 3143 fps | 97% |
| Ramshot Big Game | <<locked>> | 86% | 45,658 psi | 89% | 3104 fps | 97.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,549 psi | 69% | 2070 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 46,209 psi | 90% | 3166 fps | 97.6% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 46,006 psi | 89% | 3205 fps | 99.9% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 46,398 psi | 90% | 3163 fps | 96.8% |
| Rottweil R 902 | <<locked>> | 84% | 44,759 psi | 87% | 3012 fps | 98.9% |
| Rottweil R 903 | <<locked>> | 90% | 46,180 psi | 90% | 3091 fps | 98.7% |
| Shooters World Match Rifle | <<locked>> | 82% | 44,527 psi | 86% | 3045 fps | 99.7% |
| Shooters World Precision | <<locked>> | 86% | 45,818 psi | 89% | 3054 fps | 99.1% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 44,628 psi | 87% | 3087 fps | 97.8% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 46,006 psi | 89% | 3045 fps | 96.2% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 43,743 psi | 85% | 3022 fps | 97.6% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 45,977 psi | 89% | 2976 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 45,832 psi | 89% | 2972 fps | 100% |
| Somchem S335 | <<locked>> | 82% | 45,484 psi | 88% | 2972 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 45,542 psi | 88% | 3041 fps | 97.9% |
| Somchem S355 | <<locked>> | 88% | 43,787 psi | 85% | 3031 fps | 98.1% |
| Somchem S365 | <<locked>> | 98% | 44,295 psi | 86% | 3143 fps | 99.4% |
| Vihtavuori N133 | <<locked>> | 82% | 46,166 psi | 90% | 2969 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 44,280 psi | 86% | 3002 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 45,194 psi | 88% | 3009 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 44,962 psi | 87% | 3022 fps | 99.3% |
| Vihtavuori N160 | <<locked>> | 94% | 45,542 psi | 88% | 3081 fps | 96.6% |
| Vihtavuori N540 | <<locked>> | 86% | 46,514 psi | 90% | 3051 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 44,831 psi | 87% | 3081 fps | 96.3% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 40,001 psi | 78% | 3048 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 46,122 psi | 90% | 3061 fps | 98.8% |
| Winchester StaBALL Match | <<locked>> | 84% | 46,267 psi | 90% | 3087 fps | 98.6% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 38,812 psi | 75% | 2894 fps | 100% |
| Accurate 4064 | <<locked>> | 80% | 36,637 psi | 71% | 2871 fps | 99.2% |
| Accurate 4350 | <<locked>> | 92% | 40,437 psi | 79% | 3012 fps | 95.4% |
| ADI AR 2206H | <<locked>> | 80% | 42,598 psi | 83% | 3002 fps | 97.3% |
| ADI AR 2208 | <<locked>> | 82% | 38,580 psi | 75% | 2887 fps | 95.4% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 41,162 psi | 80% | 3071 fps | 95.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 35,505 psi | 69% | 2848 fps | 96.2% |
| Alliant Reloder-15 | <<locked>> | 80% | 38,392 psi | 75% | 2920 fps | 95.5% |
| Alliant Reloder-16 | <<locked>> | 92% | 40,248 psi | 78% | 3022 fps | 95.3% |
| Alliant Reloder-17 | 43 gr | 84% | 35,157 psi | 68% | 2913 fps | 95.2% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 41,597 psi | 81% | 2989 fps | 95.9% |
| Bofors RP3 | <<locked>> | 80% | 35,157 psi | 68% | 2848 fps | 96.2% |
| Hodgdon BL-C2 | <<locked>> | 80% | 43,221 psi | 84% | 3031 fps | 99% |
| Hodgdon H380 | <<locked>> | 84% | 41,292 psi | 80% | 2976 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 43,004 psi | 84% | 3018 fps | 97.9% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 34,737 psi | 67% | 2841 fps | 95.3% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 38,783 psi | 75% | 2969 fps | 97.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,150 psi | 51% | 1811 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 41,060 psi | 80% | 2959 fps | 97.4% |
| IMR 3031 | <<locked>> | 80% | 42,061 psi | 82% | 3018 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 37,855 psi | 74% | 2864 fps | 95.4% |
| IMR 4831 | <<locked>> | 94% | 41,655 psi | 81% | 3022 fps | 95.9% |
| IMR 4895 | <<locked>> | 80% | 39,320 psi | 76% | 2956 fps | 96.5% |
| Lovex D073.6 | <<locked>> | 80% | 41,597 psi | 81% | 2982 fps | 99.4% |
| Lovex S060 | <<locked>> | 80% | 42,714 psi | 83% | 2940 fps | 97.4% |
| Lovex S062 | <<locked>> | 80% | 37,782 psi | 73% | 2874 fps | 97.4% |
| Norma 201 | <<locked>> | 80% | 41,626 psi | 81% | 2953 fps | 98.3% |
| Norma 202 | <<locked>> | 80% | 41,785 psi | 81% | 2966 fps | 99.7% |
| Norma 203B | <<locked>> | 80% | 37,782 psi | 73% | 2907 fps | 95.9% |
| Norma URP | <<locked>> | 92% | 40,509 psi | 79% | 3012 fps | 95.2% |
| Ramshot Big Game | <<locked>> | 80% | 37,159 psi | 72% | 2910 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,295 psi | 51% | 1850 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 39,827 psi | 77% | 3022 fps | 95.9% |
| ReloadSwiss RS 60 | 41 gr | 80% | 32,822 psi | 64% | 2864 fps | 96.9% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 43,279 psi | 84% | 3097 fps | 95.9% |
| Rottweil R 902 | <<locked>> | 80% | 39,726 psi | 77% | 2900 fps | 97.8% |
| Rottweil R 903 | <<locked>> | 82% | 35,273 psi | 69% | 2841 fps | 95.9% |
| Shooters World Match Rifle | <<locked>> | 80% | 41,597 psi | 81% | 2982 fps | 99.4% |
| Shooters World Precision | <<locked>> | 80% | 37,782 psi | 73% | 2874 fps | 97.4% |
| SNPE Vectan SP 11 | 41.3 gr | 82% | 36,289 psi | 70% | 2894 fps | 95.2% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 42,728 psi | 83% | 2976 fps | 95.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 40,973 psi | 80% | 2959 fps | 96.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 42,960 psi | 83% | 2913 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 35,563 psi | 69% | 2756 fps | 99.4% |
| Somchem S335 | <<locked>> | 80% | 42,641 psi | 83% | 2917 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 42,395 psi | 82% | 2976 fps | 97.2% |
| Somchem S355 | <<locked>> | 80% | 33,939 psi | 66% | 2795 fps | 95.1% |
| Somchem S365 | <<locked>> | 88% | 31,763 psi | 62% | 2822 fps | 95.6% |
| Vihtavuori N133 | <<locked>> | 80% | 43,149 psi | 84% | 2913 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 38,725 psi | 75% | 2890 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 39,494 psi | 77% | 2894 fps | 99.6% |
| Vihtavuori N150 | <<locked>> | 80% | 32,169 psi | 62% | 2723 fps | 96.1% |
| Vihtavuori N160 | <<locked>> | 92% | 42,540 psi | 83% | 3018 fps | 95.8% |
| Vihtavuori N540 | <<locked>> | 80% | 38,174 psi | 74% | 2874 fps | 99.2% |
| Vihtavuori N550 | <<locked>> | 92% | 41,959 psi | 81% | 3018 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 98% | 37,275 psi | 72% | 2982 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 35,244 psi | 68% | 2812 fps | 95.7% |
| Winchester StaBALL Match | <<locked>> | 80% | 40,509 psi | 79% | 2966 fps | 97.4% |
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 81 powders for .257 Roberts loaded with the .257 | 90gr | Prvi Partizan HP. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,205 fps; across all powders the maximum-charge window runs from 2,024 fps to 3,205 fps. Accurate 3100 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 (355 MPa), the top charges use 64–90 %, leaving at least 10 % headroom. The 90.0 gr projectile in 0.257" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-23, Alliant Reloder-26 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. ReloadSwiss RS 60, Alliant Reloder-17, SNPE Vectan SP 11 rank at the top here: for .257 Roberts with the .257 | 90gr | Prvi Partizan HP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 2700, Accurate 3100, Alliant Reloder-26 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.