Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 180gr | Speer RN bullet and 66 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Vihtavuori N570 and ReloadSwiss RS 76.
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>> | 90% | 58,363 psi | 90% | 2848 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 58,697 psi | 90% | 2874 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 57,348 psi | 88% | 2949 fps | 99.1% |
| ADI AR 2209 | <<locked>> | 86% | 55,825 psi | 86% | 2881 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 90% | 58,204 psi | 90% | 2949 fps | 99.7% |
| ADI AR 2217 | <<locked>> | 98% | 56,637 psi | 87% | 2917 fps | 99.8% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 53,345 psi | 82% | 2953 fps | 97.2% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 55,288 psi | 85% | 2936 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 55,985 psi | 86% | 2877 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 82% | 55,854 psi | 86% | 2874 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 55,376 psi | 85% | 2871 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 90% | 58,581 psi | 90% | 2943 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 56,333 psi | 87% | 2854 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 56,608 psi | 87% | 2920 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 57,261 psi | 88% | 2940 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 54,824 psi | 84% | 2943 fps | 97.5% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 55,013 psi | 85% | 2848 fps | 97.6% |
| Bofors RP15 | <<locked>> | 92% | 57,725 psi | 89% | 2930 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 56,391 psi | 87% | 2930 fps | 99.8% |
| Bofors RP5 | <<locked>> | 90% | 58,581 psi | 90% | 2943 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 58,320 psi | 90% | 2940 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 57,348 psi | 88% | 2884 fps | 99.3% |
| Hodgdon H4831 SC | <<locked>> | 88% | 56,173 psi | 86% | 2867 fps | 99.2% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 56,159 psi | 86% | 2799 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 55,564 psi | 86% | 2999 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,565 psi | 58% | 1867 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 58,247 psi | 90% | 2861 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 55,230 psi | 85% | 2812 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 57,609 psi | 89% | 2864 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 90% | 56,347 psi | 87% | 2930 fps | 99.6% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 50,647 psi | 78% | 2854 fps | 99.2% |
| Lovex S065 | <<locked>> | 82% | 58,189 psi | 90% | 2835 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 56,724 psi | 87% | 2838 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,202 psi | 86% | 2818 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,854 psi | 86% | 2861 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 51,503 psi | 79% | 2877 fps | 100% |
| Norma MRP | <<locked>> | 88% | 58,769 psi | 90% | 2963 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,681 psi | 87% | 2854 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 57,580 psi | 89% | 2949 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 82% | 55,796 psi | 86% | 2858 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 56,231 psi | 87% | 2881 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,450 psi | 59% | 1906 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 57,522 psi | 89% | 2920 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 56,695 psi | 87% | 2989 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 56,173 psi | 86% | 2953 fps | 99.2% |
| Rottweil R 904 | <<locked>> | 86% | 56,507 psi | 87% | 2854 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 86% | 55,100 psi | 85% | 2864 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 82% | 58,189 psi | 90% | 2835 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 56,724 psi | 87% | 2838 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,217 psi | 88% | 2792 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 58,465 psi | 90% | 2913 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 58,189 psi | 90% | 2841 fps | 99.4% |
| Somchem S365 | <<locked>> | 84% | 58,218 psi | 90% | 2854 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,492 psi | 85% | 2831 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 58,305 psi | 90% | 2844 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 55,463 psi | 85% | 2815 fps | 100% |
| Vihtavuori N170 | <<locked>> | 96% | 58,523 psi | 90% | 2884 fps | 96.6% |
| Vihtavuori N550 | <<locked>> | 82% | 57,551 psi | 89% | 2848 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 58,233 psi | 90% | 2881 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 58,146 psi | 89% | 2959 fps | 99.5% |
| Vihtavuori N565 | <<locked>> | 92% | 55,172 psi | 85% | 2890 fps | 99.4% |
| Vihtavuori N568 | <<locked>> | 96% | 56,478 psi | 87% | 2953 fps | 98.9% |
| Vihtavuori N570 | <<locked>> | 98% | 57,885 psi | 89% | 3012 fps | 97.7% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 57,899 psi | 89% | 2789 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 56,115 psi | 86% | 2936 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 55,390 psi | 85% | 2828 fps | 99.9% |
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% | 41,510 psi | 64% | 2585 fps | 99.6% |
| Accurate 4350 | <<locked>> | 80% | 54,694 psi | 84% | 2818 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 43,018 psi | 66% | 2700 fps | 96.1% |
| ADI AR 2209 | <<locked>> | 80% | 45,484 psi | 70% | 2710 fps | 98.7% |
| ADI AR 2213 | <<locked>> | 80% | 40,857 psi | 63% | 2648 fps | 96.6% |
| ADI AR 2217 | <<locked>> | 86% | 37,289 psi | 57% | 2562 fps | 95.8% |
| ADI AR 2218 | <<locked>> | 98% | 49,443 psi | 76% | 2881 fps | 96.1% |
| ADI AR 2225 | <<locked>> | 82% | 29,791 psi | 46% | 2408 fps | 95.5% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 45,847 psi | 71% | 2710 fps | 98.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,228 psi | 80% | 2822 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,411 psi | 70% | 2703 fps | 98.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,539 psi | 64% | 2654 fps | 98% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,292 psi | 62% | 2605 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,737 psi | 53% | 2536 fps | 99% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,440 psi | 70% | 2759 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 46,978 psi | 72% | 2805 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 45,426 psi | 70% | 2677 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 38,638 psi | 59% | 2592 fps | 97.1% |
| Bofors RP30 | <<locked>> | 84% | 37,217 psi | 57% | 2579 fps | 96% |
| Bofors RP5 | <<locked>> | 80% | 41,539 psi | 64% | 2654 fps | 98% |
| Hodgdon H1000 | <<locked>> | 82% | 35,389 psi | 54% | 2520 fps | 95.7% |
| Hodgdon H4831 | <<locked>> | 80% | 43,468 psi | 67% | 2651 fps | 96.8% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,714 psi | 66% | 2635 fps | 96.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,153 psi | 76% | 2700 fps | 100% |
| Hodgdon Retumbo | 77.8 gr | 80% | 33,968 psi | 52% | 2562 fps | 96.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,195 psi | 43% | 1673 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,155 psi | 79% | 2756 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 51,590 psi | 79% | 2759 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,570 psi | 69% | 2648 fps | 97.2% |
| IMR 7828 SSC | <<locked>> | 80% | 39,566 psi | 61% | 2628 fps | 96.3% |
| IMR 8133 Enduron | <<locked>> | 90% | 35,708 psi | 55% | 2559 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 54,824 psi | 84% | 2789 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,258 psi | 82% | 2785 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,665 psi | 55% | 2464 fps | 98.5% |
| Norma 204 | <<locked>> | 80% | 52,141 psi | 80% | 2805 fps | 99.5% |
| Norma 217 | <<locked>> | 86% | 31,328 psi | 48% | 2467 fps | 95.6% |
| Norma MRP | <<locked>> | 80% | 44,048 psi | 68% | 2723 fps | 99.4% |
| Norma URP | <<locked>> | 80% | 53,084 psi | 82% | 2802 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,421 psi | 61% | 2635 fps | 96.7% |
| Ramshot Hunter | <<locked>> | 80% | 52,199 psi | 80% | 2805 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,476 psi | 55% | 2516 fps | 97.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,906 psi | 44% | 1713 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,577 psi | 82% | 2864 fps | 100% |
| ReloadSwiss RS 76 | 83.2 gr | 80% | 33,199 psi | 51% | 2533 fps | 97.2% |
| ReloadSwiss RS 80 | <<locked>> | 88% | 41,147 psi | 63% | 2687 fps | 95.8% |
| Rottweil R 904 | <<locked>> | 80% | 46,340 psi | 71% | 2687 fps | 98.1% |
| Rottweil R 905 | <<locked>> | 80% | 45,107 psi | 69% | 2697 fps | 98.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,824 psi | 84% | 2789 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,258 psi | 82% | 2785 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,664 psi | 83% | 2740 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,759 psi | 69% | 2690 fps | 98.7% |
| Somchem S361 | <<locked>> | 80% | 47,500 psi | 73% | 2674 fps | 97.8% |
| Somchem S365 | <<locked>> | 80% | 50,734 psi | 78% | 2756 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,542 psi | 70% | 2671 fps | 99.4% |
| Vihtavuori N160 | <<locked>> | 80% | 54,447 psi | 84% | 2792 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,624 psi | 61% | 2549 fps | 98% |
| Vihtavuori N170 | <<locked>> | 94% | 54,694 psi | 84% | 2825 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 53,853 psi | 83% | 2795 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,686 psi | 69% | 2680 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,801 psi | 67% | 2717 fps | 97% |
| Vihtavuori N565 | <<locked>> | 82% | 38,899 psi | 60% | 2595 fps | 95.7% |
| Vihtavuori N568 | <<locked>> | 88% | 42,192 psi | 65% | 2700 fps | 95.5% |
| Vihtavuori N570 | 94.8 gr | 94% | 49,850 psi | 77% | 2881 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,969 psi | 83% | 2740 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 38,029 psi | 59% | 2651 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,887 psi | 64% | 2602 fps | 98.1% |
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 66 powders for .300 Rem. Ultra Mag. loaded with the .308 | 180gr | Speer RN. Vihtavuori N570 delivers the highest muzzle velocity at 3,012 fps; across all powders the maximum-charge window runs from 1,867 fps to 3,012 fps. ADI AR 2218 gives the best case fill at 100 %, and 66 of the 66 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 180.0 gr projectile in 0.308" calls for a 1:16.0 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, 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, Vihtavuori N570, ReloadSwiss RS 76 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 180gr | Speer 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.