Load Specifications
Load data in caliber 6.5-300 Weatherby Mag. with .257 | 115gr | Federal Trophy Bonded bullet and 60 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ReloadSwiss RS 76 and ReloadSwiss RS 80.
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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You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 88% | 55,796 psi | 86% | 3159 fps | 100% |
| Accurate High Country | <<locked>> | 86% | 57,551 psi | 89% | 3317 fps | 99.3% |
| Accurate MAGPRO | <<locked>> | 88% | 58,784 psi | 90% | 3327 fps | 98.7% |
| ADI AR 2209 | <<locked>> | 86% | 56,855 psi | 88% | 3251 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 88% | 55,434 psi | 85% | 3261 fps | 99% |
| ADI AR 2217 | <<locked>> | 98% | 58,088 psi | 89% | 3297 fps | 99.6% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 54,592 psi | 84% | 3323 fps | 96.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 56,826 psi | 87% | 3314 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 57,087 psi | 88% | 3245 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 82% | 56,956 psi | 88% | 3245 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 56,463 psi | 87% | 3235 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 88% | 55,898 psi | 86% | 3255 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 90% | 57,580 psi | 89% | 3222 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 57,914 psi | 89% | 3294 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 58,697 psi | 90% | 3317 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 56,188 psi | 86% | 3310 fps | 96.7% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 56,144 psi | 86% | 3209 fps | 97% |
| Bofors RP15 | <<locked>> | 90% | 55,100 psi | 85% | 3238 fps | 99.5% |
| Bofors RP30 | <<locked>> | 96% | 57,783 psi | 89% | 3304 fps | 99.6% |
| Bofors RP5 | <<locked>> | 88% | 55,898 psi | 86% | 3255 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 94% | 55,521 psi | 85% | 3255 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 88% | 58,305 psi | 90% | 3255 fps | 98.9% |
| Hodgdon H4831 SC | <<locked>> | 88% | 57,348 psi | 88% | 3235 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 57,217 psi | 88% | 3163 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 57,058 psi | 88% | 3386 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,594 psi | 58% | 2103 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 55,463 psi | 85% | 3166 fps | 99.9% |
| IMR 4831 | <<locked>> | 82% | 56,304 psi | 87% | 3176 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 58,697 psi | 90% | 3232 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 90% | 57,725 psi | 89% | 3307 fps | 99.3% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 51,924 psi | 80% | 3212 fps | 98.7% |
| Lovex S070 | <<locked>> | 82% | 57,812 psi | 89% | 3202 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 57,450 psi | 88% | 3186 fps | 100% |
| Norma 204 | <<locked>> | 82% | 56,797 psi | 87% | 3228 fps | 99.6% |
| Norma 217ᴾ | <<locked>> | 100% | 53,113 psi | 82% | 3245 fps | 99.9% |
| Norma MRP | <<locked>> | 86% | 55,883 psi | 86% | 3271 fps | 100% |
| Norma URP | <<locked>> | 82% | 57,856 psi | 89% | 3222 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 54,795 psi | 84% | 3258 fps | 99.2% |
| Ramshot Hunter | <<locked>> | 82% | 56,782 psi | 87% | 3225 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 57,566 psi | 89% | 3251 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,464 psi | 59% | 2152 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 58,798 psi | 90% | 3294 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 58,349 psi | 90% | 3373 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 57,522 psi | 89% | 3327 fps | 98.7% |
| Rottweil R 904 | <<locked>> | 86% | 57,464 psi | 88% | 3219 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 86% | 56,333 psi | 87% | 3228 fps | 99.7% |
| Shooters World SW4350 | <<locked>> | 82% | 57,812 psi | 89% | 3202 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 58,378 psi | 90% | 3153 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 55,941 psi | 86% | 3225 fps | 99.7% |
| Somchem S361 | <<locked>> | 84% | 55,347 psi | 85% | 3143 fps | 98.5% |
| Somchem S365 | <<locked>> | 82% | 55,448 psi | 85% | 3166 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 56,681 psi | 87% | 3196 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 90% | 56,565 psi | 87% | 3179 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 82% | 58,639 psi | 90% | 3215 fps | 100% |
| Vihtavuori N555 | <<locked>> | 86% | 55,724 psi | 86% | 3196 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 55,376 psi | 85% | 3268 fps | 98.6% |
| Vihtavuori N565 | <<locked>> | 92% | 56,463 psi | 87% | 3258 fps | 99% |
| Vihtavuori N568 | <<locked>> | 96% | 58,030 psi | 89% | 3327 fps | 98.4% |
| Winchester StaBALL HD | <<locked>> | 90% | 57,914 psi | 89% | 3317 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 56,478 psi | 87% | 3192 fps | 99.7% |
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 3100 | <<locked>> | 80% | 42,409 psi | 65% | 2907 fps | 99.2% |
| Accurate High Country | <<locked>> | 80% | 46,528 psi | 72% | 3100 fps | 97.3% |
| Accurate MAGPRO | <<locked>> | 80% | 44,019 psi | 68% | 3031 fps | 95.2% |
| ADI AR 2209 | <<locked>> | 80% | 46,514 psi | 72% | 3051 fps | 98.2% |
| ADI AR 2213 | <<locked>> | 80% | 41,814 psi | 64% | 2976 fps | 95.8% |
| ADI AR 2217 | <<locked>> | 88% | 40,973 psi | 63% | 2949 fps | 96% |
| ADI AR 2218 | <<locked>> | 98% | 50,560 psi | 78% | 3238 fps | 95% |
| ADI AR 2225 | <<locked>> | 84% | 32,605 psi | 50% | 2762 fps | 95.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 46,760 psi | 72% | 3051 fps | 98.3% |
| Alliant Reloder-16 | <<locked>> | 80% | 53,330 psi | 82% | 3182 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,325 psi | 71% | 3041 fps | 98.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,540 psi | 65% | 2986 fps | 97.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 41,191 psi | 63% | 2930 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,650 psi | 55% | 2841 fps | 98.4% |
| Alliant Reloder-26 | <<locked>> | 80% | 46,702 psi | 72% | 3107 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 51,996 psi | 80% | 3232 fps | 95.6% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 49,269 psi | 76% | 3081 fps | 95.2% |
| Bofors RP15 | <<locked>> | 80% | 39,479 psi | 61% | 2910 fps | 96.2% |
| Bofors RP30 | <<locked>> | 84% | 38,261 psi | 59% | 2894 fps | 95% |
| Bofors RP5 | <<locked>> | 80% | 42,540 psi | 65% | 2986 fps | 97.4% |
| Hodgdon H1000 | <<locked>> | 84% | 38,841 psi | 60% | 2900 fps | 95.8% |
| Hodgdon H4831 | <<locked>> | 80% | 44,353 psi | 68% | 2982 fps | 96% |
| Hodgdon H4831 SC | <<locked>> | 80% | 43,642 psi | 67% | 2966 fps | 95.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 50,198 psi | 77% | 3051 fps | 100% |
| Hodgdon Retumbo | 66.6 gr | 80% | 34,766 psi | 54% | 2867 fps | 95% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,181 psi | 43% | 1883 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 52,141 psi | 80% | 3107 fps | 99.7% |
| IMR 4831 | <<locked>> | 80% | 52,649 psi | 81% | 3114 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,426 psi | 70% | 2976 fps | 96.5% |
| IMR 7828 SSC | <<locked>> | 80% | 40,408 psi | 62% | 2949 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 92% | 39,334 psi | 61% | 2936 fps | 95.2% |
| Lovex S070 | <<locked>> | 80% | 54,143 psi | 83% | 3140 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 36,492 psi | 56% | 2769 fps | 97.9% |
| Norma 204 | <<locked>> | 80% | 53,055 psi | 82% | 3159 fps | 99.2% |
| Norma 217 | <<locked>> | 88% | 34,621 psi | 53% | 2831 fps | 95.7% |
| Norma MRP | <<locked>> | 80% | 45,092 psi | 69% | 3061 fps | 99% |
| Norma URP | <<locked>> | 80% | 54,056 psi | 83% | 3159 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 40,582 psi | 62% | 2966 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 53,127 psi | 82% | 3163 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 36,434 psi | 56% | 2825 fps | 96.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,008 psi | 45% | 1932 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 54,795 psi | 84% | 3232 fps | 100% |
| ReloadSwiss RS 76 | 71.3 gr | 80% | 34,127 psi | 53% | 2838 fps | 96.2% |
| ReloadSwiss RS 80 | 80.8 gr | 90% | 45,629 psi | 70% | 3091 fps | 95.9% |
| Rottweil R 904 | <<locked>> | 80% | 47,297 psi | 73% | 3025 fps | 97.5% |
| Rottweil R 905 | <<locked>> | 80% | 45,905 psi | 71% | 3028 fps | 98.3% |
| Shooters World SW4350 | <<locked>> | 80% | 54,143 psi | 83% | 3140 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 54,607 psi | 84% | 3094 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 45,585 psi | 70% | 3025 fps | 98.2% |
| Somchem S361 | <<locked>> | 80% | 48,414 psi | 75% | 3012 fps | 97.2% |
| Somchem S365 | <<locked>> | 80% | 51,924 psi | 80% | 3110 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,528 psi | 72% | 3009 fps | 99% |
| Vihtavuori N165 | <<locked>> | 80% | 40,451 psi | 62% | 2864 fps | 97.4% |
| Vihtavuori N550 | <<locked>> | 80% | 54,926 psi | 85% | 3156 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,847 psi | 71% | 3018 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 44,788 psi | 69% | 3051 fps | 96.2% |
| Vihtavuori N565 | <<locked>> | 84% | 42,888 psi | 66% | 2986 fps | 95.9% |
| Vihtavuori N568 | <<locked>> | 90% | 46,731 psi | 72% | 3107 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 80% | 39,247 psi | 60% | 2976 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 42,873 psi | 66% | 2930 fps | 97.5% |
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 60 powders for 6.5-300 Weatherby Mag. loaded with the .257 | 115gr | Federal Trophy Bonded. Hodgdon Retumbo delivers the highest muzzle velocity at 3,386 fps; across all powders the maximum-charge window runs from 2,103 fps to 3,386 fps. ADI AR 2218 gives the best case fill at 100 %, and 60 of the 60 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 58–90 %, leaving at least 10 % headroom. The 115.0 gr projectile in 0.264" calls for a 1:7.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, 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. Hodgdon Retumbo, ReloadSwiss RS 76, ReloadSwiss RS 80 rank at the top here: for 6.5-300 Weatherby Mag. with the .257 | 115gr | Federal Trophy Bonded 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.