Load Specifications
Load data in caliber .257 Roberts with .257 | 90gr | Winchester Soft-Point bullet and 62 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 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.
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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 86% | 45,803 psi | 89% | 3025 fps | 100% |
| Accurate 4064 | <<locked>> | 88% | 45,832 psi | 89% | 3064 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 44,672 psi | 87% | 3097 fps | 96.4% |
| ADI AR 2206H | <<locked>> | 82% | 44,063 psi | 86% | 3028 fps | 97.5% |
| ADI AR 2208 | <<locked>> | 88% | 45,107 psi | 88% | 3025 fps | 97.1% |
| ADI Benchmark 8208 | <<locked>> | 82% | 46,209 psi | 90% | 3045 fps | 98.9% |
| Alliant AR-Comp | <<locked>> | 82% | 45,818 psi | 89% | 3041 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 46,093 psi | 90% | 3179 fps | 97.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 44,730 psi | 87% | 3054 fps | 98.5% |
| Alliant Reloder-15 | <<locked>> | 86% | 45,136 psi | 88% | 3068 fps | 97.3% |
| Alliant Reloder-16 | <<locked>> | 96% | 44,483 psi | 86% | 3114 fps | 96.5% |
| Alliant Reloder-17 | <<locked>> | 92% | 44,715 psi | 87% | 3150 fps | 98.3% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 46,427 psi | 90% | 3087 fps | 97% |
| Bofors RP3 | <<locked>> | 88% | 44,570 psi | 87% | 3058 fps | 98.5% |
| Hodgdon BL-C2 | <<locked>> | 82% | 44,802 psi | 87% | 3058 fps | 99.1% |
| Hodgdon H380 | <<locked>> | 88% | 45,847 psi | 89% | 3064 fps | 96.1% |
| Hodgdon H4895 | <<locked>> | 82% | 44,411 psi | 86% | 3038 fps | 98.1% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 46,369 psi | 90% | 3104 fps | 98.5% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 46,093 psi | 90% | 3123 fps | 98.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,983 psi | 68% | 2008 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 45,484 psi | 88% | 3045 fps | 98.2% |
| IMR 3031 | <<locked>> | 82% | 43,729 psi | 85% | 3048 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 44,570 psi | 87% | 3009 fps | 97.2% |
| IMR 4831 | <<locked>> | 98% | 45,934 psi | 89% | 3104 fps | 96.8% |
| IMR 4895 | <<locked>> | 86% | 46,253 psi | 90% | 3104 fps | 98.1% |
| IMR 8208 XBR | <<locked>> | 82% | 46,209 psi | 90% | 3045 fps | 98.9% |
| Lovex D073.6 | <<locked>> | 84% | 46,093 psi | 90% | 3068 fps | 99.8% |
| Lovex S060 | <<locked>> | 82% | 44,179 psi | 86% | 2959 fps | 97.6% |
| Lovex S062 | <<locked>> | 86% | 44,324 psi | 86% | 3015 fps | 98.7% |
| Norma 201 | <<locked>> | 84% | 45,992 psi | 89% | 3038 fps | 98.9% |
| Norma 202 | <<locked>> | 84% | 46,253 psi | 90% | 3051 fps | 99.9% |
| Norma 203B | <<locked>> | 86% | 44,440 psi | 86% | 3054 fps | 97.6% |
| Norma URP | <<locked>> | 96% | 44,556 psi | 87% | 3094 fps | 96.3% |
| Ramshot Big Game | <<locked>> | 86% | 44,367 psi | 86% | 3071 fps | 97.5% |
| Ramshot Wild Boar | <<locked>> | 82% | 45,716 psi | 89% | 3064 fps | 97.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,317 psi | 69% | 2054 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 44,237 psi | 86% | 3117 fps | 97% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 44,556 psi | 87% | 3163 fps | 99.8% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 44,570 psi | 87% | 3117 fps | 96% |
| Rottweil R 902 | <<locked>> | 86% | 46,354 psi | 90% | 3035 fps | 99% |
| Rottweil R 903 | <<locked>> | 90% | 44,396 psi | 86% | 3048 fps | 98.3% |
| Shooters World Match Rifle | <<locked>> | 84% | 46,093 psi | 90% | 3068 fps | 99.8% |
| Shooters World Precision | <<locked>> | 86% | 44,324 psi | 86% | 3015 fps | 98.7% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 46,093 psi | 90% | 3110 fps | 97.9% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 45,324 psi | 88% | 3048 fps | 97.8% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 44,701 psi | 87% | 2943 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 44,701 psi | 87% | 2943 fps | 100% |
| Somchem S335 | <<locked>> | 82% | 44,338 psi | 86% | 2943 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 44,266 psi | 86% | 3009 fps | 97.5% |
| Somchem S355 | <<locked>> | 90% | 45,411 psi | 88% | 3058 fps | 98.3% |
| Somchem S365ᴾ | <<locked>> | 100% | 45,629 psi | 89% | 3166 fps | 99.4% |
| Vihtavuori N133 | <<locked>> | 82% | 44,904 psi | 87% | 2940 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 45,759 psi | 89% | 3022 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 43,729 psi | 85% | 2976 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 92% | 46,485 psi | 90% | 3041 fps | 99.3% |
| Vihtavuori N160 | <<locked>> | 94% | 44,005 psi | 85% | 3041 fps | 96% |
| Vihtavuori N530 | <<locked>> | 82% | 46,296 psi | 90% | 3038 fps | 99% |
| Vihtavuori N540 | <<locked>> | 86% | 45,165 psi | 88% | 3015 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 96% | 46,151 psi | 90% | 3100 fps | 96.4% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 44,701 psi | 87% | 3025 fps | 98.3% |
| Winchester 748 | <<locked>> | 82% | 45,687 psi | 89% | 3087 fps | 99.4% |
| Winchester StaBALL Match | <<locked>> | 84% | 44,933 psi | 87% | 3054 fps | 98.3% |
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% | 37,420 psi | 73% | 2858 fps | 100% |
| Accurate 4064 | <<locked>> | 80% | 35,346 psi | 69% | 2835 fps | 98.9% |
| Accurate 4350 | <<locked>> | 94% | 41,771 psi | 81% | 3038 fps | 95.6% |
| ADI AR 2206H | <<locked>> | 80% | 41,452 psi | 81% | 2969 fps | 96.8% |
| ADI AR 2208 | <<locked>> | 84% | 39,929 psi | 78% | 2910 fps | 95.6% |
| ADI Benchmark 8208 | <<locked>> | 80% | 43,482 psi | 84% | 2986 fps | 98.4% |
| Alliant AR-Comp | <<locked>> | 80% | 42,873 psi | 83% | 2992 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 39,958 psi | 78% | 3031 fps | 95.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 34,389 psi | 67% | 2808 fps | 95.6% |
| Alliant Reloder-15 | <<locked>> | 82% | 39,653 psi | 77% | 2943 fps | 95.7% |
| Alliant Reloder-16 | 43.4 gr | 94% | 41,553 psi | 81% | 3045 fps | 95.5% |
| Alliant Reloder-17 | 42.8 gr | 86% | 36,492 psi | 71% | 2946 fps | 95.6% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 40,321 psi | 78% | 2953 fps | 95.2% |
| Bofors RP3 | <<locked>> | 80% | 33,982 psi | 66% | 2808 fps | 95.5% |
| Hodgdon BL-C2 | <<locked>> | 80% | 41,843 psi | 81% | 2995 fps | 98.6% |
| Hodgdon H380 | <<locked>> | 86% | 42,801 psi | 83% | 3002 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 41,771 psi | 81% | 2982 fps | 97.5% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 35,781 psi | 69% | 2864 fps | 95.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 37,449 psi | 73% | 2930 fps | 96.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,976 psi | 50% | 1798 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 39,943 psi | 78% | 2923 fps | 96.9% |
| IMR 3031 | <<locked>> | 80% | 40,959 psi | 80% | 2992 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 39,378 psi | 76% | 2894 fps | 95.7% |
| IMR 4831 | <<locked>> | 94% | 40,103 psi | 78% | 2979 fps | 95.1% |
| IMR 4895 | <<locked>> | 80% | 38,116 psi | 74% | 2920 fps | 95.9% |
| IMR 8208 XBR | <<locked>> | 80% | 43,482 psi | 84% | 2986 fps | 98.4% |
| Lovex D073.6 | <<locked>> | 80% | 40,074 psi | 78% | 2943 fps | 99.1% |
| Lovex S060 | <<locked>> | 80% | 41,611 psi | 81% | 2904 fps | 96.9% |
| Lovex S062 | <<locked>> | 80% | 36,608 psi | 71% | 2838 fps | 96.8% |
| Norma 201 | <<locked>> | 80% | 40,408 psi | 78% | 2917 fps | 97.9% |
| Norma 202 | <<locked>> | 80% | 40,538 psi | 79% | 2933 fps | 99.5% |
| Norma 203B | <<locked>> | 80% | 36,622 psi | 71% | 2871 fps | 95.3% |
| Norma URP | <<locked>> | 94% | 41,843 psi | 81% | 3035 fps | 95.4% |
| Ramshot Big Game | <<locked>> | 82% | 38,479 psi | 75% | 2933 fps | 95.7% |
| Ramshot Wild Boar | <<locked>> | 80% | 42,801 psi | 83% | 3002 fps | 97.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,107 psi | 51% | 1837 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 38,566 psi | 75% | 2986 fps | 95.2% |
| ReloadSwiss RS 60 | 39.8 gr | 80% | 31,720 psi | 62% | 2818 fps | 96.1% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 41,510 psi | 81% | 3048 fps | 95.1% |
| Rottweil R 902 | <<locked>> | 80% | 38,537 psi | 75% | 2864 fps | 97.4% |
| Rottweil R 903 | <<locked>> | 82% | 34,142 psi | 66% | 2808 fps | 95.2% |
| Shooters World Match Rifle | <<locked>> | 80% | 40,074 psi | 78% | 2943 fps | 99.1% |
| Shooters World Precision | <<locked>> | 80% | 36,608 psi | 71% | 2838 fps | 96.8% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 37,550 psi | 73% | 2920 fps | 95.5% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 39,885 psi | 77% | 2927 fps | 96.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 42,003 psi | 82% | 2887 fps | 99.6% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 34,693 psi | 67% | 2726 fps | 99.2% |
| Somchem S335 | <<locked>> | 80% | 41,481 psi | 81% | 2884 fps | 99.9% |
| Somchem S341 | <<locked>> | 80% | 41,075 psi | 80% | 2940 fps | 96.6% |
| Somchem S355 | <<locked>> | 82% | 35,186 psi | 68% | 2822 fps | 95.4% |
| Somchem S365 | <<locked>> | 90% | 32,866 psi | 64% | 2848 fps | 95.9% |
| Vihtavuori N133 | <<locked>> | 80% | 42,177 psi | 82% | 2890 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 37,637 psi | 73% | 2861 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 38,319 psi | 74% | 2861 fps | 99.4% |
| Vihtavuori N150 | <<locked>> | 80% | 31,125 psi | 60% | 2687 fps | 95.4% |
| Vihtavuori N160 | <<locked>> | 92% | 41,031 psi | 80% | 2976 fps | 95.1% |
| Vihtavuori N530 | <<locked>> | 80% | 43,468 psi | 84% | 2982 fps | 98.5% |
| Vihtavuori N540 | <<locked>> | 80% | 37,115 psi | 72% | 2844 fps | 98.9% |
| Vihtavuori N550 | <<locked>> | 94% | 43,395 psi | 84% | 3045 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 36,463 psi | 71% | 2831 fps | 95.9% |
| Winchester 748 | <<locked>> | 80% | 42,583 psi | 83% | 3022 fps | 99% |
| Winchester StaBALL Match | <<locked>> | 80% | 39,175 psi | 76% | 2927 fps | 96.8% |
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 62 powders for .257 Roberts loaded with the .257 | 90gr | Winchester Soft-Point. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,179 fps; across all powders the maximum-charge window runs from 2,008 fps to 3,179 fps. Hodgdon Hybrid 100V gives the best case fill at 100 %, and 62 of the 62 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (355 MPa), the top charges use 68–90 %, leaving at least 10 % headroom. The 90.0 gr projectile in 0.257" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Hodgdon Hybrid 100V, Hodgdon TrailBoss, ReloadSwiss RS 14 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, Alliant Reloder-16 rank at the top here: for .257 Roberts with the .257 | 90gr | Winchester Soft-Point 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.