Load Specifications
Load data in caliber 6.5-300 Weatherby Mag. with .264 | 123gr | Warner Tool Co. Flat Line bullet and 51 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N570, Alliant Reloder-33 and Hodgdon Retumbo.
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 3100 | <<locked>> | 88% | 58,624 psi | 90% | 3117 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 57,638 psi | 89% | 3222 fps | 99% |
| ADI AR 2209 | <<locked>> | 84% | 55,854 psi | 86% | 3146 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 88% | 58,363 psi | 90% | 3225 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 96% | 57,334 psi | 88% | 3202 fps | 99.8% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 58,088 psi | 89% | 3323 fps | 98% |
| ADI AR 2225 | <<locked>> | 98% | 56,289 psi | 87% | 3219 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 56,115 psi | 86% | 3146 fps | 99.9% |
| Alliant Reloder-19 | <<locked>> | 84% | 55,535 psi | 85% | 3136 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 88% | 58,798 psi | 90% | 3219 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 56,811 psi | 87% | 3120 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 57,363 psi | 88% | 3196 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 57,711 psi | 89% | 3212 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 55,680 psi | 86% | 3222 fps | 97.3% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 55,434 psi | 85% | 3205 fps | 96.7% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 58,639 psi | 90% | 3179 fps | 98.1% |
| Bofors RP15 | <<locked>> | 90% | 58,204 psi | 90% | 3209 fps | 99.9% |
| Bofors RP30 | <<locked>> | 94% | 57,261 psi | 88% | 3212 fps | 99.8% |
| Bofors RP5 | <<locked>> | 88% | 58,798 psi | 90% | 3219 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 54,868 psi | 84% | 3159 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 86% | 57,246 psi | 88% | 3153 fps | 99.2% |
| Hodgdon H4831 SC | <<locked>> | 86% | 56,101 psi | 86% | 3133 fps | 99.1% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 56,144 psi | 86% | 3058 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 56,507 psi | 87% | 3284 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,840 psi | 58% | 2047 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 58,030 psi | 89% | 3123 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 57,508 psi | 89% | 3130 fps | 99.3% |
| IMR 7828 SSC | <<locked>> | 88% | 56,724 psi | 87% | 3202 fps | 99.5% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 55,448 psi | 85% | 3196 fps | 99.6% |
| Lovex S071 | <<locked>> | 92% | 56,797 psi | 87% | 3091 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 56,652 psi | 87% | 3222 fps | 100% |
| Norma MRP | <<locked>> | 84% | 55,042 psi | 85% | 3169 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 58,349 psi | 90% | 3232 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 90% | 56,666 psi | 87% | 3153 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,769 psi | 60% | 2093 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 57,653 psi | 89% | 3274 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 57,000 psi | 88% | 3232 fps | 99.1% |
| Rottweil R 904 | <<locked>> | 84% | 56,318 psi | 87% | 3114 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 84% | 55,390 psi | 85% | 3130 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 58,682 psi | 90% | 3186 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 57,740 psi | 89% | 3107 fps | 99.3% |
| Somchem S365 | <<locked>> | 82% | 58,508 psi | 90% | 3120 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 55,506 psi | 85% | 3094 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 55,637 psi | 86% | 3081 fps | 100% |
| Vihtavuori N555 | <<locked>> | 84% | 54,969 psi | 85% | 3097 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 58,508 psi | 90% | 3238 fps | 99.4% |
| Vihtavuori N565 | <<locked>> | 90% | 55,651 psi | 86% | 3163 fps | 99.3% |
| Vihtavuori N568 | <<locked>> | 94% | 57,377 psi | 88% | 3235 fps | 98.8% |
| Vihtavuori N570 | <<locked>> | 96% | 58,740 psi | 90% | 3301 fps | 97.5% |
| Winchester StaBALL HD | <<locked>> | 88% | 57,421 psi | 88% | 3215 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 55,492 psi | 85% | 3091 fps | 99.8% |
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% | 44,846 psi | 69% | 2881 fps | 99.8% |
| Accurate MAGPRO | <<locked>> | 80% | 46,731 psi | 72% | 3012 fps | 96.9% |
| ADI AR 2209 | <<locked>> | 80% | 48,805 psi | 75% | 3018 fps | 99.1% |
| ADI AR 2213 | <<locked>> | 80% | 44,106 psi | 68% | 2953 fps | 97.3% |
| ADI AR 2217 | <<locked>> | 84% | 37,666 psi | 58% | 2795 fps | 95.6% |
| ADI AR 2218 | <<locked>> | 96% | 49,879 psi | 77% | 3156 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 30,197 psi | 46% | 2621 fps | 95.2% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 49,211 psi | 76% | 3018 fps | 99.2% |
| Alliant Reloder-19 | <<locked>> | 80% | 48,762 psi | 75% | 3012 fps | 99.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 44,889 psi | 69% | 2956 fps | 98.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 43,540 psi | 67% | 2894 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 37,811 psi | 58% | 2822 fps | 99.4% |
| Alliant Reloder-26 | <<locked>> | 80% | 49,835 psi | 77% | 3081 fps | 100% |
| Alliant Reloder-33 | 82.8 gr | 92% | 47,834 psi | 74% | 3068 fps | 95.1% |
| Alliant Reloder-50 | <<locked>> | 98% | 51,372 psi | 79% | 3127 fps | 95.6% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 48,327 psi | 74% | 2986 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 41,829 psi | 64% | 2887 fps | 97.7% |
| Bofors RP30 | <<locked>> | 82% | 37,869 psi | 58% | 2812 fps | 95.7% |
| Bofors RP5 | <<locked>> | 80% | 44,889 psi | 69% | 2956 fps | 98.5% |
| Hodgdon H1000 | <<locked>> | 80% | 35,708 psi | 55% | 2746 fps | 95.4% |
| Hodgdon H4831 | <<locked>> | 80% | 46,572 psi | 72% | 2953 fps | 97.4% |
| Hodgdon H4831 SC | <<locked>> | 80% | 45,803 psi | 70% | 2936 fps | 97.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 52,634 psi | 81% | 3002 fps | 100% |
| Hodgdon Retumbo | 66.7 gr | 80% | 36,898 psi | 57% | 2861 fps | 97.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,413 psi | 44% | 1834 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 54,360 psi | 84% | 3061 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,442 psi | 73% | 2943 fps | 97.8% |
| IMR 7828 SSC | <<locked>> | 80% | 42,917 psi | 66% | 2933 fps | 97% |
| IMR 8133 Enduron | <<locked>> | 88% | 36,637 psi | 56% | 2795 fps | 95% |
| Lovex S071 | <<locked>> | 80% | 38,667 psi | 60% | 2746 fps | 99% |
| Norma 217 | <<locked>> | 84% | 32,155 psi | 49% | 2690 fps | 95.3% |
| Norma MRP | <<locked>> | 80% | 47,892 psi | 74% | 3038 fps | 99.7% |
| Ramshot Grand | <<locked>> | 80% | 43,149 psi | 66% | 2946 fps | 97.5% |
| Ramshot Magnum | <<locked>> | 80% | 38,957 psi | 60% | 2812 fps | 97.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,124 psi | 45% | 1873 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 36,318 psi | 56% | 2835 fps | 98% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 42,003 psi | 65% | 2930 fps | 95.5% |
| Rottweil R 904 | <<locked>> | 80% | 49,414 psi | 76% | 2989 fps | 98.6% |
| Rottweil R 905 | <<locked>> | 80% | 48,443 psi | 75% | 3002 fps | 99.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 48,095 psi | 74% | 2995 fps | 99.1% |
| Somchem S361 | <<locked>> | 80% | 50,575 psi | 78% | 2979 fps | 98.3% |
| Somchem S365 | <<locked>> | 80% | 54,607 psi | 84% | 3061 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 48,791 psi | 75% | 2972 fps | 99.6% |
| Vihtavuori N165 | <<locked>> | 80% | 42,728 psi | 66% | 2841 fps | 98.6% |
| Vihtavuori N555 | <<locked>> | 80% | 48,341 psi | 74% | 2982 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 47,456 psi | 73% | 3031 fps | 97.7% |
| Vihtavuori N565 | <<locked>> | 80% | 39,494 psi | 61% | 2828 fps | 95.5% |
| Vihtavuori N568 | <<locked>> | 86% | 42,946 psi | 66% | 2949 fps | 95.2% |
| Vihtavuori N570 | 79.6 gr | 92% | 50,749 psi | 78% | 3150 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 80% | 42,279 psi | 65% | 2953 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,078 psi | 69% | 2900 fps | 98.6% |
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 51 powders for 6.5-300 Weatherby Mag. loaded with the .264 | 123gr | Warner Tool Co. Flat Line. ADI AR 2218 delivers the highest muzzle velocity at 3,323 fps; across all powders the maximum-charge window runs from 2,047 fps to 3,323 fps. ADI AR 2218 gives the best case fill at 100 %, and 51 of the 51 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 123.0 gr projectile in 0.264" calls for a 1:7.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, Alliant Reloder-50, 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. Vihtavuori N570, Alliant Reloder-33, Hodgdon Retumbo rank at the top here: for 6.5-300 Weatherby Mag. with the .264 | 123gr | Warner Tool Co. Flat Line 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.