Load Specifications
Load data in caliber .257 Roberts with .257 | 86gr | Winchester SPRN 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 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 2015 | <<locked>> | 82% | 46,253 psi | 90% | 3054 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 44,019 psi | 85% | 3058 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 45,643 psi | 89% | 3110 fps | 99.6% |
| Accurate 4064 | <<locked>> | 88% | 44,063 psi | 86% | 3091 fps | 99.8% |
| Accurate 4350 | <<locked>> | 98% | 46,035 psi | 89% | 3186 fps | 96.2% |
| ADI AR 2206H | <<locked>> | 84% | 45,295 psi | 88% | 3110 fps | 97.3% |
| ADI AR 2208 | <<locked>> | 90% | 46,398 psi | 90% | 3110 fps | 96.9% |
| ADI Benchmark 8208 | <<locked>> | 82% | 44,773 psi | 87% | 3071 fps | 98.3% |
| Alliant AR-Comp | <<locked>> | 82% | 44,063 psi | 86% | 3077 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 45,890 psi | 89% | 3136 fps | 98.3% |
| Alliant Reloder-15 | <<locked>> | 88% | 46,325 psi | 90% | 3150 fps | 97.1% |
| Alliant Reloder-16 | <<locked>> | 98% | 45,614 psi | 89% | 3192 fps | 96.2% |
| Alliant Reloder-17 | <<locked>> | 94% | 46,166 psi | 90% | 3235 fps | 98.1% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 44,831 psi | 87% | 3110 fps | 96.1% |
| Bofors RP3 | <<locked>> | 90% | 46,006 psi | 89% | 3146 fps | 98.4% |
| Hodgdon BL-C2 | <<locked>> | 84% | 46,253 psi | 90% | 3146 fps | 99% |
| Hodgdon H4895 | <<locked>> | 84% | 45,687 psi | 89% | 3127 fps | 97.9% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 44,628 psi | 87% | 3123 fps | 97.7% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 44,382 psi | 86% | 3146 fps | 98.1% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,766 psi | 68% | 2047 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 44,034 psi | 86% | 3071 fps | 97.5% |
| IMR 3031 | <<locked>> | 84% | 44,933 psi | 87% | 3136 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 45,847 psi | 89% | 3094 fps | 97% |
| IMR 4895 | <<locked>> | 86% | 44,643 psi | 87% | 3127 fps | 97.3% |
| IMR 8208 XBR | <<locked>> | 82% | 44,773 psi | 87% | 3071 fps | 98.3% |
| Lovex D073.6 | <<locked>> | 84% | 44,382 psi | 86% | 3094 fps | 99.4% |
| Lovex S060 | <<locked>> | 84% | 45,890 psi | 89% | 3051 fps | 97.5% |
| Lovex S062 | <<locked>> | 88% | 45,571 psi | 89% | 3097 fps | 98.6% |
| Norma 201 | <<locked>> | 84% | 44,512 psi | 86% | 3064 fps | 98.3% |
| Norma 202 | <<locked>> | 84% | 44,701 psi | 87% | 3081 fps | 99.7% |
| Norma 203B | <<locked>> | 88% | 45,556 psi | 88% | 3136 fps | 97.4% |
| Norma URP | <<locked>> | 98% | 45,963 psi | 89% | 3182 fps | 96.1% |
| Ramshot Big Game | <<locked>> | 88% | 45,788 psi | 89% | 3156 fps | 97.3% |
| Ramshot Wild Boar | <<locked>> | 82% | 44,179 psi | 86% | 3087 fps | 97% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,085 psi | 68% | 2093 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 45,643 psi | 89% | 3209 fps | 96.8% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 45,977 psi | 89% | 3251 fps | 99.7% |
| Rottweil R 901 | <<locked>> | 82% | 45,759 psi | 89% | 3071 fps | 99.7% |
| Rottweil R 902 | <<locked>> | 86% | 44,846 psi | 87% | 3064 fps | 98.4% |
| Rottweil R 903 | <<locked>> | 92% | 45,818 psi | 89% | 3136 fps | 98.1% |
| Shooters World Match Rifle | <<locked>> | 84% | 44,382 psi | 86% | 3094 fps | 99.4% |
| Shooters World Precision | <<locked>> | 88% | 45,571 psi | 89% | 3097 fps | 98.6% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 44,411 psi | 86% | 3133 fps | 97.1% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 43,816 psi | 85% | 3071 fps | 97% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 46,195 psi | 90% | 3031 fps | 99.8% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 46,079 psi | 89% | 3028 fps | 100% |
| Somchem S335 | <<locked>> | 84% | 45,629 psi | 89% | 3028 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 45,716 psi | 89% | 3094 fps | 97.3% |
| Somchem S355 | <<locked>> | 92% | 46,586 psi | 90% | 3140 fps | 98.1% |
| Somchem S365ᴾ | <<locked>> | 100% | 43,801 psi | 85% | 3182 fps | 98.8% |
| Vihtavuori N133 | <<locked>> | 84% | 46,311 psi | 90% | 3028 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 44,106 psi | 86% | 3054 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 45,266 psi | 88% | 3064 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 92% | 44,817 psi | 87% | 3071 fps | 98.8% |
| Vihtavuori N530 | <<locked>> | 82% | 44,802 psi | 87% | 3068 fps | 98.4% |
| Vihtavuori N540 | <<locked>> | 86% | 43,642 psi | 85% | 3045 fps | 99.6% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 46,180 psi | 90% | 3107 fps | 98.2% |
| Winchester 748 | <<locked>> | 82% | 44,034 psi | 86% | 3110 fps | 98.9% |
| Winchester StaBALL Match | <<locked>> | 86% | 46,398 psi | 90% | 3140 fps | 98.1% |
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% | 43,439 psi | 84% | 2999 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 35,940 psi | 70% | 2884 fps | 99.9% |
| Accurate 2520 | <<locked>> | 80% | 42,554 psi | 83% | 3045 fps | 99.2% |
| Accurate 4064 | <<locked>> | 80% | 33,939 psi | 66% | 2854 fps | 98.2% |
| Accurate 4350 | <<locked>> | 96% | 42,714 psi | 83% | 3114 fps | 95.3% |
| ADI AR 2206H | <<locked>> | 80% | 40,089 psi | 78% | 2992 fps | 95.9% |
| ADI AR 2208 | <<locked>> | 86% | 41,075 psi | 80% | 2992 fps | 95.4% |
| ADI Benchmark 8208 | <<locked>> | 80% | 42,105 psi | 82% | 3015 fps | 97.7% |
| Alliant AR-Comp | <<locked>> | 80% | 41,220 psi | 80% | 3025 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 35,520 psi | 69% | 2894 fps | 95.4% |
| Alliant Reloder-15 | <<locked>> | 84% | 40,683 psi | 79% | 3025 fps | 95.5% |
| Alliant Reloder-16 | <<locked>> | 96% | 42,960 psi | 83% | 3130 fps | 95.3% |
| Alliant Reloder-17 | 43.8 gr | 88% | 37,623 psi | 73% | 3028 fps | 95.4% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 41,887 psi | 81% | 3045 fps | 95.2% |
| Bofors RP3 | <<locked>> | 82% | 34,838 psi | 68% | 2887 fps | 95.3% |
| Hodgdon BL-C2 | <<locked>> | 80% | 40,335 psi | 78% | 3018 fps | 97.9% |
| Hodgdon H4895 | <<locked>> | 80% | 40,379 psi | 78% | 3009 fps | 96.6% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 36,709 psi | 71% | 2936 fps | 95.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 36,085 psi | 70% | 2946 fps | 95.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,802 psi | 50% | 1834 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 38,653 psi | 75% | 2946 fps | 96% |
| IMR 3031 | <<locked>> | 80% | 39,392 psi | 77% | 3018 fps | 99.9% |
| IMR 4064 | <<locked>> | 84% | 40,524 psi | 79% | 2976 fps | 95.5% |
| IMR 4895 | <<locked>> | 82% | 39,146 psi | 76% | 3002 fps | 95.7% |
| IMR 8208 XBR | <<locked>> | 80% | 42,105 psi | 82% | 3015 fps | 97.7% |
| Lovex D073.6 | <<locked>> | 80% | 38,551 psi | 75% | 2966 fps | 98.4% |
| Lovex S060 | <<locked>> | 80% | 40,408 psi | 78% | 2930 fps | 96.1% |
| Lovex S062 | <<locked>> | 80% | 35,346 psi | 69% | 2861 fps | 95.9% |
| Norma 201 | <<locked>> | 80% | 39,088 psi | 76% | 2943 fps | 97.1% |
| Norma 202 | <<locked>> | 80% | 39,160 psi | 76% | 2959 fps | 99% |
| Norma 203B | <<locked>> | 82% | 37,594 psi | 73% | 2949 fps | 95.1% |
| Norma URP | <<locked>> | 96% | 42,844 psi | 83% | 3110 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 84% | 39,682 psi | 77% | 3018 fps | 95.5% |
| Ramshot Wild Boar | <<locked>> | 80% | 41,350 psi | 80% | 3025 fps | 96.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,889 psi | 50% | 1873 fps | 100% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 39,827 psi | 77% | 3074 fps | 95.1% |
| ReloadSwiss RS 60 | 40.8 gr | 82% | 32,764 psi | 64% | 2900 fps | 95.9% |
| Rottweil R 901 | <<locked>> | 80% | 43,076 psi | 84% | 3015 fps | 99.4% |
| Rottweil R 902 | <<locked>> | 80% | 37,275 psi | 72% | 2890 fps | 96.5% |
| Rottweil R 903 | <<locked>> | 84% | 34,998 psi | 68% | 2884 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 38,551 psi | 75% | 2966 fps | 98.4% |
| Shooters World Precision | <<locked>> | 80% | 35,346 psi | 69% | 2861 fps | 95.9% |
| SNPE Vectan SP 11 | 42.1 gr | 86% | 38,769 psi | 75% | 3002 fps | 95.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 38,551 psi | 75% | 2949 fps | 95.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 40,727 psi | 79% | 2917 fps | 99.2% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 33,547 psi | 65% | 2753 fps | 98.6% |
| Somchem S335 | <<locked>> | 80% | 40,190 psi | 78% | 2917 fps | 99.6% |
| Somchem S341 | <<locked>> | 80% | 39,639 psi | 77% | 2959 fps | 95.6% |
| Somchem S355 | <<locked>> | 84% | 36,114 psi | 70% | 2897 fps | 95.1% |
| Somchem S365 | <<locked>> | 92% | 33,634 psi | 65% | 2920 fps | 95.5% |
| Vihtavuori N133 | <<locked>> | 80% | 40,857 psi | 79% | 2923 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 36,230 psi | 70% | 2890 fps | 99.9% |
| Vihtavuori N140 | <<locked>> | 80% | 37,014 psi | 72% | 2884 fps | 98.9% |
| Vihtavuori N150 | <<locked>> | 82% | 32,198 psi | 63% | 2769 fps | 95.3% |
| Vihtavuori N530 | <<locked>> | 80% | 42,061 psi | 82% | 3009 fps | 97.8% |
| Vihtavuori N540 | <<locked>> | 80% | 35,839 psi | 70% | 2867 fps | 98.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 37,623 psi | 73% | 2910 fps | 95.7% |
| Winchester 748 | <<locked>> | 80% | 41,031 psi | 80% | 3045 fps | 98.3% |
| Winchester StaBALL Match | <<locked>> | 80% | 37,768 psi | 73% | 2949 fps | 95.9% |
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 | 86gr | Winchester SPRN. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,251 fps; across all powders the maximum-charge window runs from 2,047 fps to 3,251 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 68–90 %, leaving at least 10 % headroom. The 86.0 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, 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, SNPE Vectan SP 11 rank at the top here: for .257 Roberts with the .257 | 86gr | Winchester SPRN 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.