Load Specifications
Load data in caliber .257 Roberts with .257 | 85gr | Lehigh Defense Controlled Chaos bullet and 59 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 Norma 203B.
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 2015 | <<locked>> | 82% | 46,006 psi | 89% | 3068 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 43,714 psi | 85% | 3068 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 45,382 psi | 88% | 3120 fps | 99.5% |
| Accurate 4064 | <<locked>> | 88% | 43,743 psi | 85% | 3100 fps | 99.8% |
| Accurate 4350 | <<locked>> | 98% | 45,658 psi | 89% | 3189 fps | 96% |
| ADI AR 2206H | <<locked>> | 84% | 45,063 psi | 88% | 3120 fps | 97.1% |
| ADI AR 2208 | <<locked>> | 90% | 46,151 psi | 90% | 3120 fps | 96.7% |
| ADI Benchmark 8208 | <<locked>> | 82% | 44,541 psi | 87% | 3084 fps | 98.2% |
| Alliant AR-Comp | <<locked>> | 82% | 43,801 psi | 85% | 3091 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 45,629 psi | 89% | 3146 fps | 98.2% |
| Alliant Reloder-15 | <<locked>> | 88% | 46,079 psi | 89% | 3159 fps | 96.9% |
| Alliant Reloder-16 | <<locked>> | 98% | 45,339 psi | 88% | 3202 fps | 96% |
| Alliant Reloder-17 | <<locked>> | 94% | 45,861 psi | 89% | 3245 fps | 97.9% |
| Bofors RP3 | <<locked>> | 90% | 45,339 psi | 88% | 3150 fps | 98.2% |
| Hodgdon Benchmark | <<locked>> | 82% | 46,528 psi | 90% | 3084 fps | 99% |
| Hodgdon BL-C2 | <<locked>> | 84% | 45,992 psi | 89% | 3156 fps | 98.9% |
| Hodgdon H4895 | <<locked>> | 84% | 45,440 psi | 88% | 3136 fps | 97.8% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 44,295 psi | 86% | 3133 fps | 97.5% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 44,077 psi | 86% | 3156 fps | 98% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,621 psi | 67% | 2057 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 46,586 psi | 90% | 3143 fps | 98% |
| IMR 3031 | <<locked>> | 84% | 44,701 psi | 87% | 3150 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 45,629 psi | 89% | 3104 fps | 96.8% |
| IMR 4831ᴾ | <<locked>> | 100% | 46,572 psi | 90% | 3189 fps | 96.4% |
| IMR 4895 | <<locked>> | 86% | 44,338 psi | 86% | 3140 fps | 97.1% |
| IMR 8208 XBR | <<locked>> | 82% | 44,541 psi | 87% | 3084 fps | 98.2% |
| Lovex D073.6 | <<locked>> | 84% | 43,830 psi | 85% | 3097 fps | 99.3% |
| Lovex S060 | <<locked>> | 84% | 45,368 psi | 88% | 3058 fps | 97.3% |
| Lovex S062 | <<locked>> | 88% | 45,310 psi | 88% | 3107 fps | 98.4% |
| Norma 201 | <<locked>> | 84% | 44,324 psi | 86% | 3077 fps | 98.2% |
| Norma 202 | <<locked>> | 84% | 44,440 psi | 86% | 3094 fps | 99.7% |
| Norma 203B | <<locked>> | 88% | 45,310 psi | 88% | 3146 fps | 97.3% |
| Ramshot Big Game | <<locked>> | 88% | 45,469 psi | 88% | 3166 fps | 97.1% |
| Ramshot Wild Boar | <<locked>> | 82% | 43,947 psi | 85% | 3100 fps | 96.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 34,911 psi | 68% | 2103 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 45,353 psi | 88% | 3215 fps | 96.6% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 45,672 psi | 89% | 3258 fps | 99.6% |
| Rottweil R 901 | <<locked>> | 82% | 45,208 psi | 88% | 3077 fps | 99.6% |
| Rottweil R 902 | <<locked>> | 86% | 44,585 psi | 87% | 3074 fps | 98.2% |
| Rottweil R 903 | <<locked>> | 92% | 45,527 psi | 88% | 3143 fps | 98% |
| Shooters World Match Rifle | <<locked>> | 84% | 43,830 psi | 85% | 3097 fps | 99.3% |
| Shooters World Precision | <<locked>> | 88% | 45,310 psi | 88% | 3107 fps | 98.4% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 44,121 psi | 86% | 3143 fps | 96.9% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 46,586 psi | 90% | 3146 fps | 97.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 45,992 psi | 89% | 3041 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 45,861 psi | 89% | 3038 fps | 100% |
| Somchem S335 | <<locked>> | 84% | 45,455 psi | 88% | 3041 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 45,455 psi | 88% | 3107 fps | 97.2% |
| Somchem S355 | <<locked>> | 92% | 46,282 psi | 90% | 3150 fps | 97.9% |
| Somchem S365ᴾ | <<locked>> | 100% | 43,439 psi | 84% | 3189 fps | 98.7% |
| Vihtavuori N133 | <<locked>> | 84% | 46,108 psi | 90% | 3041 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 43,816 psi | 85% | 3068 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 44,701 psi | 87% | 3071 fps | 99.8% |
| Vihtavuori N150 | <<locked>> | 92% | 44,556 psi | 87% | 3077 fps | 98.7% |
| Vihtavuori N530 | <<locked>> | 82% | 44,541 psi | 87% | 3077 fps | 98.3% |
| Vihtavuori N540 | <<locked>> | 88% | 46,093 psi | 90% | 3110 fps | 99.8% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 45,890 psi | 89% | 3114 fps | 98% |
| Winchester 748 | <<locked>> | 82% | 43,787 psi | 85% | 3123 fps | 98.8% |
| Winchester StaBALL Match | <<locked>> | 86% | 46,122 psi | 90% | 3150 fps | 98% |
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 2015 | <<locked>> | 80% | 43,221 psi | 84% | 3012 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 35,708 psi | 69% | 2894 fps | 99.9% |
| Accurate 2520 | <<locked>> | 80% | 42,322 psi | 82% | 3058 fps | 99.1% |
| Accurate 4064 | <<locked>> | 80% | 33,750 psi | 66% | 2864 fps | 98% |
| Accurate 4350 | <<locked>> | 96% | 42,380 psi | 82% | 3120 fps | 95% |
| ADI AR 2206H | <<locked>> | 80% | 39,639 psi | 77% | 2995 fps | 95.6% |
| ADI AR 2208 | <<locked>> | 86% | 40,886 psi | 79% | 3005 fps | 95.2% |
| ADI Benchmark 8208 | <<locked>> | 80% | 41,626 psi | 81% | 3018 fps | 97.5% |
| Alliant AR-Comp | <<locked>> | 80% | 40,944 psi | 80% | 3038 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 35,099 psi | 68% | 2897 fps | 95.1% |
| Alliant Reloder-15 | <<locked>> | 84% | 40,451 psi | 79% | 3031 fps | 95.2% |
| Alliant Reloder-16 | <<locked>> | 96% | 42,380 psi | 82% | 3130 fps | 95% |
| Alliant Reloder-17 | 43.9 gr | 88% | 37,405 psi | 73% | 3035 fps | 95.1% |
| Bofors RP3 | <<locked>> | 82% | 34,650 psi | 67% | 2897 fps | 95.1% |
| Hodgdon Benchmark | <<locked>> | 80% | 43,816 psi | 85% | 3025 fps | 98.5% |
| Hodgdon BL-C2 | <<locked>> | 80% | 40,118 psi | 78% | 3031 fps | 97.8% |
| Hodgdon H4895 | <<locked>> | 80% | 39,914 psi | 78% | 3012 fps | 96.4% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 38,798 psi | 75% | 3005 fps | 95.8% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 35,882 psi | 70% | 2956 fps | 95.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,686 psi | 50% | 1844 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 38,479 psi | 75% | 2956 fps | 95.8% |
| IMR 3031 | <<locked>> | 80% | 38,827 psi | 75% | 3022 fps | 99.8% |
| IMR 4064 | <<locked>> | 84% | 40,335 psi | 78% | 2986 fps | 95.3% |
| IMR 4831 | <<locked>> | 98% | 43,671 psi | 85% | 3130 fps | 95.6% |
| IMR 4895 | <<locked>> | 82% | 38,914 psi | 76% | 3012 fps | 95.5% |
| IMR 8208 XBR | <<locked>> | 80% | 41,626 psi | 81% | 3018 fps | 97.5% |
| Lovex D073.6 | <<locked>> | 80% | 38,290 psi | 74% | 2976 fps | 98.3% |
| Lovex S060 | <<locked>> | 80% | 40,234 psi | 78% | 2943 fps | 95.9% |
| Lovex S062 | <<locked>> | 80% | 35,172 psi | 68% | 2871 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 38,870 psi | 75% | 2953 fps | 96.9% |
| Norma 202 | <<locked>> | 80% | 38,957 psi | 76% | 2972 fps | 98.9% |
| Norma 203B | 39.9 gr | 84% | 39,769 psi | 77% | 3022 fps | 95.7% |
| Ramshot Big Game | <<locked>> | 84% | 39,450 psi | 77% | 3028 fps | 95.3% |
| Ramshot Wild Boar | <<locked>> | 80% | 40,799 psi | 79% | 3028 fps | 95.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,049 psi | 51% | 1890 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 42,177 psi | 82% | 3146 fps | 95.7% |
| ReloadSwiss RS 60 | 40.9 gr | 82% | 32,576 psi | 63% | 2907 fps | 95.6% |
| Rottweil R 901 | <<locked>> | 80% | 42,540 psi | 83% | 3022 fps | 99.3% |
| Rottweil R 902 | <<locked>> | 80% | 37,086 psi | 72% | 2897 fps | 96.3% |
| Rottweil R 903 | <<locked>> | 86% | 37,057 psi | 72% | 2953 fps | 95.6% |
| Shooters World Match Rifle | <<locked>> | 80% | 38,290 psi | 74% | 2976 fps | 98.3% |
| Shooters World Precision | <<locked>> | 80% | 35,172 psi | 68% | 2871 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 38,537 psi | 75% | 3012 fps | 95.1% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 38,363 psi | 75% | 2959 fps | 95.2% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 40,553 psi | 79% | 2930 fps | 99.2% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 33,402 psi | 65% | 2766 fps | 98.5% |
| Somchem S335 | <<locked>> | 80% | 40,016 psi | 78% | 2927 fps | 99.5% |
| Somchem S341 | <<locked>> | 80% | 39,378 psi | 76% | 2969 fps | 95.4% |
| Somchem S355 | <<locked>> | 86% | 38,203 psi | 74% | 2966 fps | 95.8% |
| Somchem S365 | <<locked>> | 92% | 33,417 psi | 65% | 2927 fps | 95.3% |
| Vihtavuori N133 | <<locked>> | 80% | 40,683 psi | 79% | 2933 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 36,027 psi | 70% | 2900 fps | 99.8% |
| Vihtavuori N140 | <<locked>> | 80% | 36,840 psi | 72% | 2897 fps | 98.8% |
| Vihtavuori N150 | <<locked>> | 82% | 31,995 psi | 62% | 2779 fps | 95.1% |
| Vihtavuori N530 | <<locked>> | 80% | 41,524 psi | 81% | 3012 fps | 97.6% |
| Vihtavuori N540 | <<locked>> | 80% | 35,650 psi | 69% | 2877 fps | 98.1% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 37,391 psi | 73% | 2920 fps | 95.4% |
| Winchester 748 | <<locked>> | 80% | 40,814 psi | 79% | 3054 fps | 98.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 37,521 psi | 73% | 2956 fps | 95.6% |
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 59 powders for .257 Roberts loaded with the .257 | 85gr | Lehigh Defense Controlled Chaos. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,258 fps; across all powders the maximum-charge window runs from 2,057 fps to 3,258 fps. Hodgdon Hybrid 100V gives the best case fill at 100 %, and 59 of the 59 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (355 MPa), the top charges use 67–90 %, leaving at least 10 % headroom. The 85.0 gr projectile in 0.257" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Hodgdon Hybrid 100V, Hodgdon TrailBoss, IMR 4831 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, Norma 203B rank at the top here: for .257 Roberts with the .257 | 85gr | Lehigh Defense Controlled Chaos 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.