Load Specifications
Load data in caliber 6.5-300 Weatherby Mag. with .264 | 140gr | Speer Grand Slam bullet and 42 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Vihtavuori N570 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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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 82% | 55,013 psi | 85% | 2890 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 55,434 psi | 85% | 3002 fps | 98.1% |
| Accurate MAGPRO | <<locked>> | 82% | 58,160 psi | 90% | 3064 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 84% | 58,740 psi | 90% | 3058 fps | 100% |
| ADI AR 2217 | <<locked>> | 92% | 58,494 psi | 90% | 3048 fps | 100% |
| ADI AR 2218 | <<locked>> | 94% | 55,390 psi | 85% | 3114 fps | 98.9% |
| ADI AR 2225 | <<locked>> | 94% | 58,682 psi | 90% | 3071 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 55,390 psi | 85% | 2989 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 84% | 57,566 psi | 89% | 2949 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 88% | 58,639 psi | 90% | 3031 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 57,566 psi | 89% | 3091 fps | 98.9% |
| Alliant Reloder-50 | <<locked>> | 96% | 58,059 psi | 89% | 3087 fps | 98.5% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 58,537 psi | 90% | 3018 fps | 99.2% |
| Bofors RP15 | <<locked>> | 86% | 58,711 psi | 90% | 3041 fps | 100% |
| Bofors RP30 | <<locked>> | 90% | 58,653 psi | 90% | 3061 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 55,390 psi | 85% | 2989 fps | 100% |
| Hodgdon H1000 | <<locked>> | 88% | 55,956 psi | 86% | 3005 fps | 100% |
| Hodgdon H4831 | <<locked>> | 82% | 57,000 psi | 88% | 2986 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 82% | 55,941 psi | 86% | 2969 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 86% | 54,752 psi | 84% | 3068 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,174 psi | 59% | 1946 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 56,942 psi | 88% | 2959 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 84% | 57,406 psi | 88% | 3045 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 55,564 psi | 86% | 2917 fps | 95.9% |
| IMR 8133 Enduron | <<locked>> | 96% | 57,551 psi | 89% | 3054 fps | 100% |
| Lovex S071 | <<locked>> | 88% | 57,348 psi | 88% | 2927 fps | 100% |
| Norma 217 | <<locked>> | 94% | 55,332 psi | 85% | 3018 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 54,955 psi | 85% | 3005 fps | 100% |
| Ramshot Magnum | <<locked>> | 86% | 57,406 psi | 88% | 2992 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,320 psi | 61% | 1991 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 55,448 psi | 85% | 3051 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 58,668 psi | 90% | 3087 fps | 99.9% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 56,971 psi | 88% | 3005 fps | 98.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 58,697 psi | 90% | 3015 fps | 100% |
| Vihtavuori N165 | <<locked>> | 84% | 55,782 psi | 86% | 2920 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 55,361 psi | 85% | 2953 fps | 97.3% |
| Vihtavuori N560 | <<locked>> | 82% | 58,682 psi | 90% | 3071 fps | 99.9% |
| Vihtavuori N565 | <<locked>> | 86% | 56,463 psi | 87% | 3012 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 88% | 54,926 psi | 85% | 3025 fps | 99.3% |
| Vihtavuori N570 | <<locked>> | 90% | 56,579 psi | 87% | 3094 fps | 98.4% |
| Winchester StaBALL HD | <<locked>> | 82% | 55,419 psi | 85% | 2989 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 82% | 55,303 psi | 85% | 2927 fps | 100% |
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% | 51,532 psi | 79% | 2838 fps | 100% |
| Accurate 8700 | <<locked>> | 94% | 44,469 psi | 68% | 2799 fps | 95.3% |
| Accurate MAGPRO | <<locked>> | 80% | 54,302 psi | 84% | 2999 fps | 99.4% |
| ADI AR 2213 | <<locked>> | 80% | 51,169 psi | 79% | 2933 fps | 99.6% |
| ADI AR 2217 | <<locked>> | 80% | 38,493 psi | 59% | 2671 fps | 97.6% |
| ADI AR 2218 | 81.2 gr | 88% | 44,164 psi | 68% | 2881 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 35,810 psi | 55% | 2641 fps | 99.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 51,895 psi | 80% | 2930 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 50,517 psi | 78% | 2844 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 44,657 psi | 69% | 2802 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 84% | 42,830 psi | 66% | 2802 fps | 95.2% |
| Alliant Reloder-50 | <<locked>> | 90% | 46,383 psi | 71% | 2867 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 48,138 psi | 74% | 2835 fps | 97.3% |
| Bofors RP15 | <<locked>> | 80% | 48,356 psi | 74% | 2864 fps | 99.8% |
| Bofors RP30 | <<locked>> | 80% | 41,785 psi | 64% | 2749 fps | 98.4% |
| Bofors RP5 | <<locked>> | 80% | 51,895 psi | 80% | 2930 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 41,959 psi | 65% | 2749 fps | 99% |
| Hodgdon H4831 | <<locked>> | 80% | 53,214 psi | 82% | 2923 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 52,402 psi | 81% | 2907 fps | 99.5% |
| Hodgdon Retumbo | <<locked>> | 80% | 44,106 psi | 68% | 2871 fps | 99.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,776 psi | 44% | 1742 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 53,287 psi | 82% | 2900 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 80% | 49,951 psi | 77% | 2917 fps | 99.5% |
| IMR 7977 Enduron | <<locked>> | 86% | 52,156 psi | 80% | 2858 fps | 95% |
| IMR 8133 Enduron | <<locked>> | 80% | 33,373 psi | 51% | 2556 fps | 95.2% |
| Lovex S071 | <<locked>> | 80% | 44,483 psi | 68% | 2713 fps | 100% |
| Norma 217 | <<locked>> | 80% | 34,069 psi | 52% | 2585 fps | 97.8% |
| Ramshot Grand | <<locked>> | 80% | 51,010 psi | 79% | 2936 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 80% | 46,180 psi | 71% | 2805 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,544 psi | 45% | 1781 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 43,976 psi | 68% | 2848 fps | 100% |
| ReloadSwiss RS 80 | 75.2 gr | 80% | 40,379 psi | 62% | 2736 fps | 96.6% |
| SNPE Vectan SP 13 | <<locked>> | 94% | 46,412 psi | 71% | 2815 fps | 95.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 54,998 psi | 85% | 2956 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 48,878 psi | 75% | 2805 fps | 100% |
| Vihtavuori N170 | <<locked>> | 84% | 48,211 psi | 74% | 2822 fps | 95.5% |
| Vihtavuori N560 | <<locked>> | 80% | 54,795 psi | 84% | 3005 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 80% | 46,166 psi | 71% | 2825 fps | 98.8% |
| Vihtavuori N568 | <<locked>> | 80% | 41,249 psi | 63% | 2749 fps | 96.3% |
| Vihtavuori N570 | 75.9 gr | 84% | 45,513 psi | 70% | 2877 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 80% | 51,372 psi | 79% | 2927 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 51,605 psi | 79% | 2867 fps | 100% |
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 42 powders for 6.5-300 Weatherby Mag. loaded with the .264 | 140gr | Speer Grand Slam. ADI AR 2218 delivers the highest muzzle velocity at 3,114 fps; across all powders the maximum-charge window runs from 1,946 fps to 3,114 fps. Accurate 8700 gives the best case fill at 100 %, and 42 of the 42 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 140.0 gr projectile in 0.264" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, 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. ADI AR 2218, Vihtavuori N570, ReloadSwiss RS 80 rank at the top here: for 6.5-300 Weatherby Mag. with the .264 | 140gr | Speer Grand Slam 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.