Load Specifications
Load data in caliber 6.5-300 Weatherby Mag. with .263 | 156gr | Prvi Partizan SP RN bullet and 39 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 Alliant Reloder-50.
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% | 58,015 psi | 89% | 2799 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 55,230 psi | 85% | 2874 fps | 98.9% |
| ADI AR 2213 | <<locked>> | 82% | 57,943 psi | 89% | 2907 fps | 100% |
| ADI AR 2217 | <<locked>> | 90% | 58,204 psi | 90% | 2904 fps | 100% |
| ADI AR 2218 | <<locked>> | 92% | 55,042 psi | 85% | 2979 fps | 99.5% |
| ADI AR 2225 | <<locked>> | 92% | 58,479 psi | 90% | 2927 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 82% | 58,552 psi | 90% | 2897 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 82% | 56,956 psi | 88% | 2799 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 86% | 58,262 psi | 90% | 2884 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 57,232 psi | 88% | 2953 fps | 99.4% |
| Alliant Reloder-50 | <<locked>> | 94% | 57,812 psi | 89% | 2956 fps | 99.2% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 57,522 psi | 89% | 2871 fps | 99.6% |
| Bofors RP15 | <<locked>> | 84% | 58,204 psi | 90% | 2894 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 58,189 psi | 90% | 2917 fps | 100% |
| Bofors RP5 | <<locked>> | 82% | 58,552 psi | 90% | 2897 fps | 100% |
| Hodgdon H1000 | <<locked>> | 86% | 55,361 psi | 85% | 2858 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 58,682 psi | 90% | 2982 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 38,276 psi | 59% | 1844 fps | 100% |
| IMR 7828 SSC | <<locked>> | 82% | 56,724 psi | 87% | 2894 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 88% | 58,276 psi | 90% | 2838 fps | 97.5% |
| IMR 8133 Enduron | <<locked>> | 94% | 57,464 psi | 88% | 2920 fps | 100% |
| Lovex D100 | <<locked>> | 90% | 56,289 psi | 87% | 2835 fps | 96.1% |
| Lovex S071 | <<locked>> | 86% | 56,913 psi | 88% | 2782 fps | 100% |
| Norma 217 | <<locked>> | 92% | 55,361 psi | 85% | 2881 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 58,436 psi | 90% | 2920 fps | 100% |
| Ramshot LRT | <<locked>> | 94% | 58,465 psi | 90% | 2972 fps | 96.2% |
| Ramshot Magnum | <<locked>> | 84% | 56,927 psi | 88% | 2848 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,479 psi | 61% | 1890 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 84% | 55,042 psi | 85% | 2904 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 58,175 psi | 90% | 2946 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 90% | 56,289 psi | 87% | 2835 fps | 96.1% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 56,753 psi | 87% | 2877 fps | 98.8% |
| Vihtavuori 20N29ᴾ | <<locked>> | 100% | 54,070 psi | 83% | 2854 fps | 97.1% |
| Vihtavuori N165 | <<locked>> | 84% | 58,595 psi | 90% | 2825 fps | 100% |
| Vihtavuori N170 | <<locked>> | 88% | 58,363 psi | 90% | 2874 fps | 98.7% |
| Vihtavuori N565 | <<locked>> | 84% | 56,101 psi | 86% | 2871 fps | 100% |
| Vihtavuori N568 | <<locked>> | 88% | 58,508 psi | 90% | 2953 fps | 100% |
| Vihtavuori N570 | <<locked>> | 88% | 56,362 psi | 87% | 2956 fps | 99.1% |
| Winchester Supreme 780 | <<locked>> | 82% | 58,117 psi | 89% | 2831 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% | 54,331 psi | 84% | 2746 fps | 100% |
| Accurate 8700 | <<locked>> | 90% | 41,278 psi | 64% | 2615 fps | 95.5% |
| ADI AR 2213 | <<locked>> | 80% | 54,128 psi | 83% | 2848 fps | 100% |
| ADI AR 2217 | <<locked>> | 80% | 41,046 psi | 63% | 2608 fps | 99.1% |
| ADI AR 2218 | 75.8 gr | 84% | 40,901 psi | 63% | 2690 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 38,464 psi | 59% | 2582 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 54,810 psi | 84% | 2841 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 80% | 53,505 psi | 82% | 2749 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 47,732 psi | 73% | 2723 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 80% | 39,581 psi | 61% | 2612 fps | 95.3% |
| Alliant Reloder-50 | 78.8 gr | 86% | 43,265 psi | 67% | 2684 fps | 96% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 50,502 psi | 78% | 2753 fps | 98.7% |
| Bofors RP15 | <<locked>> | 80% | 51,068 psi | 79% | 2779 fps | 100% |
| Bofors RP30 | <<locked>> | 80% | 44,512 psi | 69% | 2680 fps | 99.6% |
| Bofors RP5 | <<locked>> | 80% | 54,810 psi | 84% | 2841 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 44,788 psi | 69% | 2680 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 80% | 47,442 psi | 73% | 2802 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,819 psi | 44% | 1650 fps | 100% |
| IMR 7828 SSC | <<locked>> | 80% | 52,953 psi | 81% | 2831 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 82% | 48,167 psi | 74% | 2664 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 80% | 35,940 psi | 55% | 2507 fps | 97.6% |
| Lovex D100 | <<locked>> | 88% | 52,504 psi | 81% | 2772 fps | 95.2% |
| Lovex S071 | <<locked>> | 80% | 47,166 psi | 73% | 2631 fps | 100% |
| Norma 217 | <<locked>> | 80% | 36,724 psi | 57% | 2533 fps | 99.4% |
| Ramshot Grand | <<locked>> | 80% | 54,447 psi | 84% | 2861 fps | 100% |
| Ramshot LRT | <<locked>> | 92% | 54,447 psi | 84% | 2907 fps | 95.3% |
| Ramshot Magnum | <<locked>> | 80% | 49,168 psi | 76% | 2730 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,791 psi | 46% | 1690 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 47,398 psi | 73% | 2779 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 43,366 psi | 67% | 2684 fps | 98.5% |
| Shooters World 50 BMG | <<locked>> | 88% | 52,504 psi | 81% | 2772 fps | 95.2% |
| SNPE Vectan SP 13 | <<locked>> | 90% | 43,337 psi | 67% | 2635 fps | 95.8% |
| Vihtavuori 20N29 | <<locked>> | 96% | 46,847 psi | 72% | 2723 fps | 95.1% |
| Vihtavuori N165 | <<locked>> | 80% | 51,459 psi | 79% | 2720 fps | 100% |
| Vihtavuori N170 | <<locked>> | 80% | 44,643 psi | 69% | 2631 fps | 95.7% |
| Vihtavuori N565 | <<locked>> | 80% | 49,066 psi | 76% | 2749 fps | 99.7% |
| Vihtavuori N568 | <<locked>> | 80% | 44,208 psi | 68% | 2694 fps | 98.2% |
| Vihtavuori N570 | 70.7 gr | 80% | 42,337 psi | 65% | 2687 fps | 95.9% |
| Winchester Supreme 780 | <<locked>> | 80% | 54,375 psi | 84% | 2776 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 39 powders for 6.5-300 Weatherby Mag. loaded with the .263 | 156gr | Prvi Partizan SP RN. Hodgdon Retumbo delivers the highest muzzle velocity at 2,982 fps; across all powders the maximum-charge window runs from 1,844 fps to 2,982 fps. Hodgdon TrailBoss gives the best case fill at 100 %, and 39 of the 39 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 156.0 gr projectile in 0.263" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Hodgdon TrailBoss, ReloadSwiss RS 14, Vihtavuori 20N29 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, Alliant Reloder-50 rank at the top here: for 6.5-300 Weatherby Mag. with the .263 | 156gr | Prvi Partizan SP RN 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.