Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 220gr | Woodleigh RN SN bullet and 52 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ADI AR 2218, Hodgdon Retumbo and Vihtavuori N570.
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>> | 86% | 57,014 psi | 88% | 2598 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 48,225 psi | 74% | 2572 fps | 97.3% |
| Accurate MAGPRO | <<locked>> | 86% | 57,101 psi | 88% | 2713 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 84% | 57,957 psi | 89% | 2677 fps | 100% |
| ADI AR 2213 | <<locked>> | 86% | 56,724 psi | 87% | 2697 fps | 100% |
| ADI AR 2217 | <<locked>> | 94% | 55,941 psi | 86% | 2680 fps | 100% |
| ADI AR 2218 | <<locked>> | 98% | 56,449 psi | 87% | 2802 fps | 99.4% |
| ADI AR 2225 | <<locked>> | 96% | 55,245 psi | 85% | 2700 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 57,696 psi | 89% | 2671 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 86% | 57,246 psi | 88% | 2690 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 86% | 55,579 psi | 86% | 2605 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 90% | 56,043 psi | 86% | 2674 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 82% | 56,101 psi | 86% | 2680 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 58,392 psi | 90% | 2776 fps | 99.4% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 58,465 psi | 90% | 2772 fps | 99.1% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 57,000 psi | 88% | 2661 fps | 99.2% |
| Bofors RP15 | <<locked>> | 88% | 56,637 psi | 87% | 2684 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 55,825 psi | 86% | 2694 fps | 100% |
| Bofors RP5 | <<locked>> | 86% | 57,246 psi | 88% | 2690 fps | 100% |
| Hodgdon H1000 | <<locked>> | 92% | 57,392 psi | 88% | 2697 fps | 100% |
| Hodgdon H4831 | <<locked>> | 84% | 55,477 psi | 85% | 2635 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 86% | 58,305 psi | 90% | 2671 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 58,305 psi | 90% | 2582 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 55,405 psi | 85% | 2756 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,985 psi | 58% | 1696 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 55,709 psi | 86% | 2612 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 86% | 55,361 psi | 85% | 2684 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 92% | 57,957 psi | 89% | 2618 fps | 96.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 58,030 psi | 89% | 2740 fps | 100% |
| Lovex S071 | <<locked>> | 90% | 55,448 psi | 85% | 2579 fps | 100% |
| Norma 217 | <<locked>> | 98% | 55,709 psi | 86% | 2707 fps | 100% |
| Norma MRP | <<locked>> | 84% | 57,537 psi | 89% | 2703 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 56,608 psi | 87% | 2703 fps | 100% |
| Ramshot Magnum | <<locked>> | 88% | 55,129 psi | 85% | 2638 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,986 psi | 60% | 1739 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 56,304 psi | 87% | 2743 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 92% | 55,579 psi | 86% | 2720 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 84% | 58,218 psi | 90% | 2648 fps | 100% |
| Rottweil R 905 | <<locked>> | 84% | 57,551 psi | 89% | 2664 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 50,372 psi | 78% | 2585 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 57,174 psi | 88% | 2661 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 55,985 psi | 86% | 2592 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 57,696 psi | 89% | 2631 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 57,798 psi | 89% | 2621 fps | 100% |
| Vihtavuori N170 | <<locked>> | 92% | 57,101 psi | 88% | 2654 fps | 98.1% |
| Vihtavuori N555 | <<locked>> | 84% | 57,261 psi | 88% | 2628 fps | 100% |
| Vihtavuori N560 | <<locked>> | 84% | 56,826 psi | 87% | 2713 fps | 100% |
| Vihtavuori N565 | <<locked>> | 90% | 58,088 psi | 89% | 2707 fps | 100% |
| Vihtavuori N568 | <<locked>> | 92% | 56,043 psi | 86% | 2723 fps | 99.8% |
| Vihtavuori N570 | <<locked>> | 94% | 57,261 psi | 88% | 2782 fps | 99% |
| Winchester StaBALL HD | <<locked>> | 86% | 56,318 psi | 87% | 2690 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 57,653 psi | 89% | 2631 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% | 46,702 psi | 72% | 2457 fps | 100% |
| Accurate 8700 | <<locked>> | 96% | 41,669 psi | 64% | 2457 fps | 95.3% |
| Accurate MAGPRO | <<locked>> | 80% | 46,180 psi | 71% | 2543 fps | 98.2% |
| ADI AR 2209 | <<locked>> | 80% | 50,778 psi | 78% | 2579 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 45,992 psi | 71% | 2533 fps | 99.4% |
| ADI AR 2217 | <<locked>> | 80% | 34,374 psi | 53% | 2306 fps | 97% |
| ADI AR 2218 | 89.8 gr | 90% | 42,003 psi | 65% | 2543 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 31,691 psi | 49% | 2283 fps | 98.8% |
| Alliant Reloder-19 | <<locked>> | 80% | 50,589 psi | 78% | 2569 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 46,775 psi | 72% | 2536 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 45,629 psi | 70% | 2470 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 39,755 psi | 61% | 2431 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 52,127 psi | 80% | 2628 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 40,234 psi | 62% | 2474 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 92% | 43,366 psi | 67% | 2530 fps | 95.9% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 43,932 psi | 68% | 2454 fps | 96.8% |
| Bofors RP15 | <<locked>> | 80% | 43,613 psi | 67% | 2480 fps | 99.6% |
| Bofors RP30 | <<locked>> | 80% | 37,144 psi | 57% | 2379 fps | 97.9% |
| Bofors RP5 | <<locked>> | 80% | 46,775 psi | 72% | 2536 fps | 99.9% |
| Hodgdon H1000 | <<locked>> | 80% | 37,362 psi | 57% | 2372 fps | 98.5% |
| Hodgdon H4831 | <<locked>> | 80% | 48,472 psi | 75% | 2530 fps | 99.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 47,601 psi | 73% | 2513 fps | 99.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 54,723 psi | 84% | 2539 fps | 100% |
| Hodgdon Retumbo | 75.3 gr | 80% | 38,827 psi | 60% | 2484 fps | 99.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,427 psi | 44% | 1516 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 49,095 psi | 76% | 2513 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 80% | 44,802 psi | 69% | 2520 fps | 99.2% |
| IMR 7977 Enduron | <<locked>> | 88% | 50,981 psi | 78% | 2516 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 82% | 31,357 psi | 48% | 2264 fps | 95.6% |
| Lovex S071 | <<locked>> | 80% | 40,277 psi | 62% | 2352 fps | 100% |
| Norma 217 | <<locked>> | 80% | 29,602 psi | 46% | 2234 fps | 97.1% |
| Norma MRP | <<locked>> | 80% | 50,009 psi | 77% | 2602 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 45,339 psi | 70% | 2536 fps | 99.5% |
| Ramshot Magnum | <<locked>> | 80% | 40,930 psi | 63% | 2421 fps | 99.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,240 psi | 45% | 1555 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 38,290 psi | 59% | 2461 fps | 99.9% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 35,273 psi | 54% | 2362 fps | 95.8% |
| Rottweil R 904 | <<locked>> | 80% | 51,372 psi | 79% | 2552 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 80% | 50,270 psi | 77% | 2562 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 43,772 psi | 67% | 2477 fps | 95.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 49,922 psi | 77% | 2559 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 52,373 psi | 81% | 2543 fps | 99.7% |
| Somchem S385 | <<locked>> | 80% | 50,647 psi | 78% | 2536 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 44,425 psi | 68% | 2428 fps | 99.9% |
| Vihtavuori N170 | <<locked>> | 86% | 46,601 psi | 72% | 2490 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 50,270 psi | 77% | 2536 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 49,501 psi | 76% | 2602 fps | 99.5% |
| Vihtavuori N565 | <<locked>> | 80% | 41,278 psi | 64% | 2441 fps | 98.3% |
| Vihtavuori N568 | <<locked>> | 80% | 36,405 psi | 56% | 2379 fps | 95.6% |
| Vihtavuori N570 | 84 gr | 86% | 42,975 psi | 66% | 2543 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 44,918 psi | 69% | 2536 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 46,818 psi | 72% | 2480 fps | 99.9% |
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 59 powders for .300 Rem. Ultra Mag. loaded with the .308 | 220gr | Woodleigh RN SN. ADI AR 2218 delivers the highest muzzle velocity at 2,802 fps; across all powders the maximum-charge window runs from 1,696 fps to 2,802 fps. Accurate 8700 gives the best case fill at 100 %, and 59 of the 59 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 220.0 gr projectile in 0.308" calls for a 1:14.5 twist; slower twists will usually not stabilise this weight. Accurate 8700, 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. ADI AR 2218, Hodgdon Retumbo, Vihtavuori N570 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 220gr | Woodleigh RN SN they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Hodgdon 50BMG, Hodgdon US 869, Vihtavuori 20N29 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.