Load Specifications
Load data in caliber .257 Roberts with .257 | 100gr | CutEdge MTH bullet and 57 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 60, ReloadSwiss RS 70 and Alliant Reloder-17.
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% | 45,266 psi | 88% | 2884 fps | 100% |
| Accurate 4064 | <<locked>> | 86% | 45,542 psi | 88% | 2927 fps | 100% |
| Accurate 4350 | <<locked>> | 94% | 44,962 psi | 87% | 2982 fps | 97.7% |
| ADI AR 2206H | <<locked>> | 82% | 46,514 psi | 90% | 2953 fps | 98.9% |
| ADI AR 2208 | <<locked>> | 86% | 44,831 psi | 87% | 2904 fps | 98.1% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 45,498 psi | 88% | 3048 fps | 98.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 44,324 psi | 86% | 2923 fps | 99.2% |
| Alliant Reloder-15 | <<locked>> | 84% | 44,686 psi | 87% | 2936 fps | 98.2% |
| Alliant Reloder-16 | <<locked>> | 94% | 44,164 psi | 86% | 2992 fps | 97.8% |
| Alliant Reloder-17 | <<locked>> | 90% | 44,541 psi | 87% | 3028 fps | 99.2% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 37,913 psi | 74% | 2871 fps | 97.6% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 42,496 psi | 83% | 3038 fps | 96.7% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 46,122 psi | 90% | 2959 fps | 98% |
| Bofors RP3 | <<locked>> | 86% | 44,150 psi | 86% | 2927 fps | 99.2% |
| Hodgdon H380 | <<locked>> | 86% | 45,382 psi | 88% | 2936 fps | 97.3% |
| Hodgdon Hybrid 100V | <<locked>> | 98% | 46,557 psi | 90% | 2986 fps | 99.3% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 45,948 psi | 89% | 2992 fps | 99.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,099 psi | 68% | 1916 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 45,266 psi | 88% | 2917 fps | 99.1% |
| IMR 4064 | <<locked>> | 84% | 44,295 psi | 86% | 2884 fps | 98.2% |
| IMR 4831 | <<locked>> | 96% | 45,847 psi | 89% | 2982 fps | 98% |
| IMR 4895 | <<locked>> | 84% | 45,803 psi | 89% | 2969 fps | 98.9% |
| Lovex D073.6 | <<locked>> | 82% | 45,672 psi | 89% | 2933 fps | 100% |
| Lovex S060 | <<locked>> | 82% | 46,441 psi | 90% | 2887 fps | 98.9% |
| Lovex S062 | <<locked>> | 84% | 44,034 psi | 86% | 2884 fps | 99.4% |
| Lovex S065 | <<locked>> | 92% | 46,296 psi | 90% | 2927 fps | 96.6% |
| Norma 201 | <<locked>> | 82% | 45,179 psi | 88% | 2897 fps | 99.5% |
| Norma 202 | <<locked>> | 82% | 45,934 psi | 89% | 2913 fps | 100% |
| Norma 203B | <<locked>> | 84% | 43,976 psi | 85% | 2920 fps | 98.5% |
| Norma URP | <<locked>> | 94% | 44,817 psi | 87% | 2979 fps | 97.6% |
| Ramshot Big Game | <<locked>> | 84% | 43,947 psi | 85% | 2940 fps | 98.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,447 psi | 69% | 1959 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 44,527 psi | 86% | 2995 fps | 98.1% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 44,324 psi | 86% | 3035 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 44,701 psi | 87% | 3002 fps | 97.4% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 44,933 psi | 87% | 3022 fps | 96.9% |
| Rottweil R 902 | <<locked>> | 84% | 45,861 psi | 89% | 2904 fps | 99.6% |
| Rottweil R 903 | <<locked>> | 88% | 44,338 psi | 86% | 2923 fps | 99.1% |
| Shooters World Long Rifle | <<locked>> | 92% | 46,296 psi | 90% | 2927 fps | 96.6% |
| Shooters World Match Rifle | <<locked>> | 82% | 45,672 psi | 89% | 2933 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 44,034 psi | 86% | 2884 fps | 99.4% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 45,977 psi | 89% | 2986 fps | 98.8% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 45,165 psi | 88% | 2920 fps | 98.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 44,367 psi | 86% | 2808 fps | 100% |
| Somchem S335 | <<locked>> | 82% | 46,282 psi | 90% | 2851 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 44,918 psi | 87% | 2927 fps | 99% |
| Somchem S365 | <<locked>> | 98% | 45,701 psi | 89% | 3041 fps | 99.9% |
| Vihtavuori N135 | <<locked>> | 84% | 45,556 psi | 88% | 2884 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 46,282 psi | 90% | 2894 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 46,064 psi | 89% | 2910 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 92% | 43,845 psi | 85% | 2920 fps | 97.3% |
| Vihtavuori N540 | <<locked>> | 84% | 44,643 psi | 87% | 2881 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 46,340 psi | 90% | 2986 fps | 97.7% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 41,321 psi | 80% | 2953 fps | 97.5% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 44,324 psi | 86% | 2904 fps | 99.2% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 33,895 psi | 66% | 2848 fps | 96.8% |
| Winchester StaBALL Match | <<locked>> | 82% | 44,556 psi | 87% | 2923 fps | 99% |
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% | 39,392 psi | 77% | 2772 fps | 100% |
| Accurate 4064 | <<locked>> | 80% | 37,246 psi | 72% | 2762 fps | 99.8% |
| Accurate 4350 | <<locked>> | 88% | 36,085 psi | 70% | 2789 fps | 95.1% |
| ADI AR 2206H | <<locked>> | 80% | 43,424 psi | 84% | 2890 fps | 98.4% |
| ADI AR 2208 | <<locked>> | 80% | 36,956 psi | 72% | 2726 fps | 96% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 39,566 psi | 77% | 2913 fps | 96.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 36,419 psi | 71% | 2746 fps | 97.6% |
| Alliant Reloder-15 | <<locked>> | 80% | 39,131 psi | 76% | 2815 fps | 96.9% |
| Alliant Reloder-16 | <<locked>> | 88% | 36,419 psi | 71% | 2805 fps | 95.2% |
| Alliant Reloder-17 | 40.9 gr | 82% | 33,707 psi | 65% | 2762 fps | 96% |
| Alliant Reloder-23 | <<locked>> | 96% | 33,301 psi | 65% | 2746 fps | 95.8% |
| Alliant Reloder-26 | <<locked>> | 98% | 39,566 psi | 77% | 2966 fps | 95.6% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 42,801 psi | 83% | 2890 fps | 97.3% |
| Bofors RP3 | <<locked>> | 80% | 35,795 psi | 70% | 2743 fps | 97.5% |
| Hodgdon H380 | <<locked>> | 82% | 39,436 psi | 77% | 2812 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 31,386 psi | 61% | 2638 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 39,914 psi | 78% | 2867 fps | 98.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,034 psi | 51% | 1713 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 42,221 psi | 82% | 2854 fps | 98.6% |
| IMR 4064 | <<locked>> | 80% | 38,754 psi | 75% | 2766 fps | 96.9% |
| IMR 4831 | <<locked>> | 90% | 37,521 psi | 73% | 2805 fps | 95.7% |
| IMR 4895 | <<locked>> | 80% | 40,103 psi | 78% | 2848 fps | 97.7% |
| Lovex D073.6 | <<locked>> | 80% | 42,540 psi | 83% | 2871 fps | 99.9% |
| Lovex S060 | <<locked>> | 80% | 43,700 psi | 85% | 2831 fps | 98.5% |
| Lovex S062 | <<locked>> | 80% | 38,566 psi | 75% | 2769 fps | 98.5% |
| Lovex S065 | <<locked>> | 88% | 40,698 psi | 79% | 2808 fps | 95% |
| Norma 201 | <<locked>> | 80% | 42,438 psi | 82% | 2841 fps | 99.1% |
| Norma 202 | <<locked>> | 80% | 42,844 psi | 83% | 2854 fps | 100% |
| Norma 203B | <<locked>> | 80% | 38,493 psi | 75% | 2802 fps | 97.3% |
| Norma URP | <<locked>> | 88% | 36,666 psi | 71% | 2795 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 80% | 38,203 psi | 74% | 2815 fps | 97% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,440 psi | 51% | 1755 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 41,350 psi | 80% | 2930 fps | 97.4% |
| ReloadSwiss RS 60 | 39.9 gr | 80% | 33,547 psi | 65% | 2772 fps | 98.4% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 38,725 psi | 75% | 2874 fps | 95.6% |
| ReloadSwiss RS 70 | 46.6 gr | 92% | 41,945 psi | 81% | 2956 fps | 95.9% |
| Rottweil R 902 | <<locked>> | 80% | 40,466 psi | 79% | 2792 fps | 98.8% |
| Rottweil R 903 | <<locked>> | 80% | 33,649 psi | 65% | 2680 fps | 96.5% |
| Shooters World Long Rifle | <<locked>> | 88% | 40,698 psi | 79% | 2808 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 42,540 psi | 83% | 2871 fps | 99.9% |
| Shooters World Precision | <<locked>> | 80% | 38,566 psi | 75% | 2769 fps | 98.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 34,969 psi | 68% | 2740 fps | 96% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 42,177 psi | 82% | 2861 fps | 98.1% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 36,579 psi | 71% | 2654 fps | 99.9% |
| Somchem S335 | <<locked>> | 80% | 43,526 psi | 85% | 2802 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 34,650 psi | 67% | 2694 fps | 96.6% |
| Somchem S365 | <<locked>> | 84% | 28,485 psi | 55% | 2612 fps | 95.3% |
| Vihtavuori N135 | <<locked>> | 80% | 39,914 psi | 78% | 2782 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 40,553 psi | 79% | 2785 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 32,924 psi | 64% | 2628 fps | 97.4% |
| Vihtavuori N160 | <<locked>> | 88% | 38,276 psi | 74% | 2799 fps | 95.6% |
| Vihtavuori N540 | <<locked>> | 80% | 39,204 psi | 76% | 2769 fps | 99.8% |
| Vihtavuori N550 | <<locked>> | 88% | 37,623 psi | 73% | 2795 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 96% | 35,926 psi | 70% | 2831 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 31,546 psi | 61% | 2602 fps | 95.4% |
| Winchester StaBALL HD | <<locked>> | 98% | 31,662 psi | 61% | 2769 fps | 95.4% |
| Winchester StaBALL Match | <<locked>> | 80% | 41,553 psi | 81% | 2861 fps | 98.5% |
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 57 powders for .257 Roberts loaded with the .257 | 100gr | CutEdge MTH. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,048 fps; across all powders the maximum-charge window runs from 1,916 fps to 3,048 fps. Alliant Reloder-23 gives the best case fill at 100 %, and 57 of the 57 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (355 MPa), the top charges use 66–90 %, leaving at least 10 % headroom. The 100.0 gr projectile in 0.257" calls for a 1:9.5 twist; slower twists will usually not stabilise this weight. Alliant Reloder-23, Alliant Reloder-26, Hodgdon TrailBoss 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, ReloadSwiss RS 70, Alliant Reloder-17 rank at the top here: for .257 Roberts with the .257 | 100gr | CutEdge MTH 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.