Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 200gr | Barnes X S bullet and 52 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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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 86% | 55,216 psi | 85% | 2667 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 57,072 psi | 88% | 2812 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 84% | 55,201 psi | 85% | 2736 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 57,348 psi | 88% | 2802 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 96% | 56,101 psi | 86% | 2779 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 56,724 psi | 87% | 2887 fps | 98.6% |
| ADI AR 2225 | <<locked>> | 98% | 55,013 psi | 85% | 2802 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 55,550 psi | 85% | 2733 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 58,479 psi | 90% | 2776 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 58,117 psi | 89% | 2802 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 56,376 psi | 87% | 2717 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 56,405 psi | 87% | 2782 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 57,174 psi | 88% | 2802 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 58,653 psi | 90% | 2877 fps | 98.7% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 54,810 psi | 84% | 2812 fps | 97.6% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 57,653 psi | 89% | 2759 fps | 98.5% |
| Bofors RP15 | <<locked>> | 90% | 57,580 psi | 89% | 2795 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 56,623 psi | 87% | 2802 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 58,117 psi | 89% | 2802 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 57,638 psi | 89% | 2799 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 56,623 psi | 87% | 2740 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 86% | 55,622 psi | 86% | 2726 fps | 99.5% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 55,869 psi | 86% | 2654 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 55,361 psi | 85% | 2864 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,971 psi | 58% | 1755 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 57,406 psi | 88% | 2707 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 56,811 psi | 87% | 2717 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 88% | 55,869 psi | 86% | 2789 fps | 99.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 54,563 psi | 84% | 2792 fps | 99.9% |
| Lovex S071 | <<locked>> | 92% | 57,174 psi | 88% | 2694 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 55,724 psi | 86% | 2812 fps | 100% |
| Norma MRP | <<locked>> | 86% | 58,378 psi | 90% | 2818 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 57,101 psi | 88% | 2808 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 55,941 psi | 86% | 2746 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 39,015 psi | 60% | 1798 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 56,318 psi | 87% | 2854 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 55,927 psi | 86% | 2822 fps | 99.5% |
| Rottweil R 904 | <<locked>> | 84% | 55,941 psi | 86% | 2707 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 86% | 58,668 psi | 90% | 2772 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 58,262 psi | 90% | 2772 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 57,435 psi | 88% | 2697 fps | 99.6% |
| Somchem S365 | <<locked>> | 82% | 58,117 psi | 89% | 2710 fps | 100% |
| Somchem S385 | <<locked>> | 84% | 55,680 psi | 86% | 2697 fps | 100% |
| Vihtavuori N165 | <<locked>> | 88% | 55,376 psi | 85% | 2680 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 58,189 psi | 90% | 2753 fps | 97.1% |
| Vihtavuori N555 | <<locked>> | 86% | 58,668 psi | 90% | 2746 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 57,638 psi | 89% | 2818 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 90% | 55,492 psi | 85% | 2766 fps | 99.7% |
| Vihtavuori N568 | <<locked>> | 94% | 56,391 psi | 87% | 2822 fps | 99.3% |
| Vihtavuori N570 | <<locked>> | 96% | 57,479 psi | 88% | 2881 fps | 98.2% |
| Winchester StaBALL HD | <<locked>> | 88% | 56,347 psi | 87% | 2805 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 86% | 54,969 psi | 85% | 2687 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% | 45,716 psi | 70% | 2530 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 46,760 psi | 72% | 2648 fps | 97.9% |
| ADI AR 2209 | <<locked>> | 80% | 48,559 psi | 75% | 2631 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 80% | 44,005 psi | 68% | 2585 fps | 98.2% |
| ADI AR 2217 | <<locked>> | 80% | 33,605 psi | 52% | 2359 fps | 95.2% |
| ADI AR 2218 | <<locked>> | 94% | 45,992 psi | 71% | 2697 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 31,125 psi | 48% | 2339 fps | 97.4% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 49,023 psi | 75% | 2635 fps | 99.6% |
| Alliant Reloder-19 | <<locked>> | 80% | 48,573 psi | 75% | 2628 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 45,005 psi | 69% | 2595 fps | 99.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 43,947 psi | 68% | 2539 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 38,159 psi | 59% | 2490 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 49,559 psi | 76% | 2697 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 44,048 psi | 68% | 2635 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 94% | 44,512 psi | 69% | 2638 fps | 95% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 45,136 psi | 69% | 2552 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 42,177 psi | 65% | 2543 fps | 98.7% |
| Bofors RP30 | <<locked>> | 80% | 36,042 psi | 55% | 2438 fps | 96.5% |
| Bofors RP5 | <<locked>> | 80% | 45,005 psi | 69% | 2595 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 80% | 36,187 psi | 56% | 2425 fps | 97% |
| Hodgdon H4831 | <<locked>> | 80% | 46,586 psi | 72% | 2582 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 80% | 45,759 psi | 70% | 2569 fps | 98% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 52,605 psi | 81% | 2608 fps | 100% |
| Hodgdon Retumbo | 72.5 gr | 80% | 37,362 psi | 57% | 2533 fps | 98.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,572 psi | 44% | 1575 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 54,070 psi | 83% | 2661 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 47,326 psi | 73% | 2569 fps | 98.4% |
| IMR 7828 SSC | <<locked>> | 80% | 42,931 psi | 66% | 2575 fps | 98.1% |
| IMR 8133 Enduron | <<locked>> | 84% | 32,779 psi | 50% | 2379 fps | 95% |
| Lovex S071 | <<locked>> | 80% | 39,929 psi | 61% | 2425 fps | 99.7% |
| Norma 217 | <<locked>> | 80% | 29,153 psi | 45% | 2300 fps | 95.7% |
| Norma MRP | <<locked>> | 80% | 47,805 psi | 74% | 2664 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 42,975 psi | 66% | 2582 fps | 98.4% |
| Ramshot Magnum | <<locked>> | 80% | 39,175 psi | 60% | 2477 fps | 98.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,414 psi | 45% | 1614 fps | 100% |
| ReloadSwiss RS 76 | 77.6 gr | 80% | 36,840 psi | 57% | 2513 fps | 99.3% |
| ReloadSwiss RS 80 | 80.2 gr | 82% | 36,535 psi | 56% | 2474 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 49,385 psi | 76% | 2608 fps | 99.1% |
| Rottweil R 905 | <<locked>> | 80% | 48,501 psi | 75% | 2625 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 48,182 psi | 74% | 2618 fps | 99.6% |
| Somchem S361 | <<locked>> | 80% | 50,502 psi | 78% | 2595 fps | 98.8% |
| Somchem S365 | <<locked>> | 80% | 54,491 psi | 84% | 2664 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 49,081 psi | 76% | 2598 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 80% | 42,975 psi | 66% | 2487 fps | 99.2% |
| Vihtavuori N170 | <<locked>> | 90% | 51,329 psi | 79% | 2648 fps | 95.6% |
| Vihtavuori N555 | <<locked>> | 80% | 48,849 psi | 75% | 2612 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 47,297 psi | 73% | 2657 fps | 98.5% |
| Vihtavuori N565 | <<locked>> | 80% | 40,248 psi | 62% | 2503 fps | 97% |
| Vihtavuori N568 | <<locked>> | 84% | 40,161 psi | 62% | 2543 fps | 95.7% |
| Vihtavuori N570 | <<locked>> | 90% | 46,905 psi | 72% | 2707 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 42,380 psi | 65% | 2605 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,252 psi | 70% | 2536 fps | 99.2% |
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 52 powders for .300 Rem. Ultra Mag. loaded with the .308 | 200gr | Barnes X S. ADI AR 2218 delivers the highest muzzle velocity at 2,887 fps; across all powders the maximum-charge window runs from 1,755 fps to 2,887 fps. ADI AR 2218 gives the best case fill at 100 %, and 52 of the 52 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 200.0 gr projectile in 0.308" calls for a 1:11.0 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. Hodgdon Retumbo, ReloadSwiss RS 76, ReloadSwiss RS 80 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 200gr | Barnes X S 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.