Load Specifications
Load data in caliber .257 Roberts with .257 | 75gr | Barnes Solid BT bullet and 52 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 60, Accurate 4064 and Bofors RP3.
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>> | 84% | 44,918 psi | 87% | 3219 fps | 100% |
| Accurate 2460 | <<locked>> | 82% | 46,311 psi | 90% | 3271 fps | 99.1% |
| Accurate 2495 | <<locked>> | 90% | 45,150 psi | 88% | 3268 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 44,382 psi | 86% | 3268 fps | 98.6% |
| Accurate 4064 | <<locked>> | 92% | 44,962 psi | 87% | 3297 fps | 99.4% |
| ADI Benchmark 8208 | <<locked>> | 86% | 46,543 psi | 90% | 3287 fps | 97.5% |
| Alliant AR-Comp | <<locked>> | 86% | 45,469 psi | 88% | 3307 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 44,382 psi | 86% | 3284 fps | 96.7% |
| Alliant Reloder-17 | <<locked>> | 96% | 44,788 psi | 87% | 3369 fps | 96.1% |
| Bofors RP3 | <<locked>> | 92% | 44,193 psi | 86% | 3287 fps | 96.8% |
| Hodgdon Benchmark | <<locked>> | 84% | 46,050 psi | 89% | 3235 fps | 97.9% |
| Hodgdon BL-C2 | <<locked>> | 86% | 45,005 psi | 87% | 3301 fps | 97.8% |
| Hodgdon H4895 | <<locked>> | 86% | 44,469 psi | 86% | 3278 fps | 96.3% |
| Hodgdon LEVERevolution | <<locked>> | 90% | 46,108 psi | 90% | 3363 fps | 97.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,069 psi | 66% | 2178 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 46,064 psi | 89% | 3291 fps | 96.6% |
| IMR 3031 | <<locked>> | 88% | 46,369 psi | 90% | 3363 fps | 100% |
| IMR 4895 | <<locked>> | 90% | 45,977 psi | 89% | 3337 fps | 96.2% |
| IMR 8208 XBR | <<locked>> | 86% | 46,543 psi | 90% | 3287 fps | 97.5% |
| Lovex D073.5 | <<locked>> | 82% | 46,224 psi | 90% | 3268 fps | 98.3% |
| Lovex D073.6 | <<locked>> | 88% | 45,876 psi | 89% | 3307 fps | 98.8% |
| Lovex S060 | <<locked>> | 86% | 44,918 psi | 87% | 3202 fps | 95.8% |
| Lovex S062 | <<locked>> | 90% | 44,280 psi | 86% | 3248 fps | 97.1% |
| Norma 201 | <<locked>> | 88% | 46,195 psi | 90% | 3281 fps | 97.5% |
| Norma 202 | <<locked>> | 88% | 46,282 psi | 90% | 3297 fps | 99.3% |
| Ramshot Wild Boar | <<locked>> | 86% | 45,861 psi | 89% | 3301 fps | 96% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 34,243 psi | 67% | 2228 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 46,195 psi | 90% | 3281 fps | 98.6% |
| ReloadSwiss RS 60 | <<locked>> | 94% | 44,715 psi | 87% | 3389 fps | 98.5% |
| Rottweil R 901 | <<locked>> | 84% | 44,541 psi | 87% | 3232 fps | 98.8% |
| Rottweil R 902 | <<locked>> | 90% | 46,485 psi | 90% | 3274 fps | 97.5% |
| Rottweil R 903 | <<locked>> | 94% | 44,063 psi | 86% | 3274 fps | 96.4% |
| Shooters World Match Rifle | <<locked>> | 88% | 45,876 psi | 89% | 3307 fps | 98.8% |
| Shooters World Precision | <<locked>> | 90% | 44,280 psi | 86% | 3248 fps | 97.1% |
| SNPE Vectan SP 11 | <<locked>> | 94% | 45,832 psi | 89% | 3337 fps | 95.9% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 45,861 psi | 89% | 3291 fps | 96% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 45,194 psi | 88% | 3189 fps | 99.1% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 44,788 psi | 87% | 3182 fps | 99.6% |
| Somchem S321 | <<locked>> | 82% | 44,251 psi | 86% | 3251 fps | 97.3% |
| Somchem S335 | <<locked>> | 86% | 44,411 psi | 86% | 3186 fps | 99.5% |
| Somchem S355 | <<locked>> | 94% | 45,005 psi | 87% | 3284 fps | 96.4% |
| Somchem S365ᴾ | <<locked>> | 100% | 39,363 psi | 76% | 3238 fps | 96.1% |
| Vihtavuori N130 | <<locked>> | 82% | 45,179 psi | 88% | 3186 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 45,136 psi | 88% | 3196 fps | 100% |
| Vihtavuori N135 | <<locked>> | 90% | 45,223 psi | 88% | 3271 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 43,685 psi | 85% | 3215 fps | 99.2% |
| Vihtavuori N150 | <<locked>> | 96% | 46,166 psi | 90% | 3271 fps | 98% |
| Vihtavuori N530 | <<locked>> | 84% | 43,772 psi | 85% | 3222 fps | 96.9% |
| Vihtavuori N540 | <<locked>> | 90% | 45,310 psi | 88% | 3258 fps | 99.1% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 45,049 psi | 87% | 3235 fps | 96.4% |
| Winchester 748 | <<locked>> | 86% | 45,919 psi | 89% | 3333 fps | 98.2% |
| Winchester StaBALL Match | <<locked>> | 88% | 45,165 psi | 88% | 3291 fps | 96.5% |
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% | 39,624 psi | 77% | 3104 fps | 99.7% |
| Accurate 2460 | <<locked>> | 80% | 43,250 psi | 84% | 3205 fps | 98.6% |
| Accurate 2495 | <<locked>> | 80% | 32,068 psi | 62% | 2959 fps | 98.6% |
| Accurate 2520 | <<locked>> | 80% | 38,276 psi | 74% | 3123 fps | 97.1% |
| Accurate 4064 | 37.4 gr | 80% | 30,327 psi | 59% | 2920 fps | 95.4% |
| ADI Benchmark 8208 | <<locked>> | 80% | 38,508 psi | 75% | 3100 fps | 95.2% |
| Alliant AR-Comp | <<locked>> | 80% | 36,883 psi | 72% | 3127 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 38,914 psi | 76% | 3153 fps | 95% |
| Alliant Reloder-17 | <<locked>> | 94% | 41,843 psi | 81% | 3294 fps | 95.1% |
| Bofors RP3 | 43.5 gr | 90% | 41,162 psi | 80% | 3219 fps | 95.9% |
| Hodgdon Benchmark | <<locked>> | 80% | 40,596 psi | 79% | 3110 fps | 96.6% |
| Hodgdon BL-C2 | <<locked>> | 80% | 36,622 psi | 71% | 3097 fps | 95.3% |
| Hodgdon H4895 | <<locked>> | 84% | 41,843 psi | 81% | 3215 fps | 95.5% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 40,248 psi | 78% | 3222 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,266 psi | 49% | 1955 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 43,004 psi | 84% | 3222 fps | 95.8% |
| IMR 3031 | <<locked>> | 80% | 35,302 psi | 69% | 3104 fps | 98.6% |
| IMR 4895 | <<locked>> | 88% | 43,221 psi | 84% | 3274 fps | 95.4% |
| IMR 8208 XBR | <<locked>> | 80% | 38,508 psi | 75% | 3100 fps | 95.2% |
| Lovex D073.5 | <<locked>> | 80% | 42,888 psi | 83% | 3199 fps | 97.6% |
| Lovex D073.6 | <<locked>> | 80% | 34,534 psi | 67% | 3035 fps | 95.8% |
| Lovex S060 | <<locked>> | 84% | 42,308 psi | 82% | 3146 fps | 95% |
| Lovex S062 | <<locked>> | 86% | 38,870 psi | 75% | 3120 fps | 95.5% |
| Norma 201 | <<locked>> | 82% | 38,159 psi | 74% | 3091 fps | 95.2% |
| Norma 202 | <<locked>> | 80% | 35,534 psi | 69% | 3045 fps | 97% |
| Ramshot Wild Boar | <<locked>> | 84% | 42,888 psi | 83% | 3232 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,280 psi | 49% | 1995 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 43,178 psi | 84% | 3215 fps | 98% |
| ReloadSwiss RS 60 | 44.1 gr | 88% | 36,289 psi | 70% | 3159 fps | 95.6% |
| Rottweil R 901 | <<locked>> | 80% | 39,146 psi | 76% | 3107 fps | 97.7% |
| Rottweil R 902 | <<locked>> | 84% | 38,435 psi | 75% | 3087 fps | 95.3% |
| Rottweil R 903 | <<locked>> | 92% | 40,988 psi | 80% | 3202 fps | 95.5% |
| Shooters World Match Rifle | <<locked>> | 80% | 34,534 psi | 67% | 3035 fps | 95.8% |
| Shooters World Precision | <<locked>> | 86% | 38,870 psi | 75% | 3120 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 42,830 psi | 83% | 3268 fps | 95% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 42,902 psi | 83% | 3222 fps | 95.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 37,376 psi | 73% | 3012 fps | 97.5% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 30,574 psi | 59% | 2835 fps | 96.4% |
| Somchem S321 | <<locked>> | 80% | 41,336 psi | 80% | 3186 fps | 96.5% |
| Somchem S335 | <<locked>> | 80% | 36,811 psi | 71% | 3009 fps | 98.1% |
| Somchem S355 | <<locked>> | 92% | 42,032 psi | 82% | 3215 fps | 95.5% |
| Somchem S365 | <<locked>> | 98% | 36,753 psi | 71% | 3163 fps | 95% |
| Vihtavuori N130 | <<locked>> | 80% | 42,467 psi | 82% | 3130 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 37,420 psi | 73% | 3025 fps | 99.4% |
| Vihtavuori N135 | <<locked>> | 80% | 32,590 psi | 63% | 2972 fps | 98.6% |
| Vihtavuori N140 | <<locked>> | 80% | 33,562 psi | 65% | 2966 fps | 96.7% |
| Vihtavuori N150 | <<locked>> | 90% | 37,869 psi | 74% | 3084 fps | 95.8% |
| Vihtavuori N530 | <<locked>> | 80% | 38,319 psi | 74% | 3091 fps | 95.3% |
| Vihtavuori N540 | <<locked>> | 80% | 32,503 psi | 63% | 2943 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 42,192 psi | 82% | 3173 fps | 95.5% |
| Winchester 748 | <<locked>> | 80% | 37,246 psi | 72% | 3127 fps | 95.9% |
| Winchester StaBALL Match | <<locked>> | 86% | 42,192 psi | 82% | 3225 fps | 95.7% |
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 52 powders for .257 Roberts loaded with the .257 | 75gr | Barnes Solid BT. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,389 fps; across all powders the maximum-charge window runs from 2,178 fps to 3,389 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 52 of the 52 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 75.0 gr projectile in 0.257" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Hodgdon TrailBoss, ReloadSwiss RS 14, Somchem S365 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, Accurate 4064, Bofors RP3 rank at the top here: for .257 Roberts with the .257 | 75gr | Barnes Solid BT 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.