Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 190gr | Sierra MatchKing 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, ReloadSwiss RS 80 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>> | 90% | 58,334 psi | 90% | 2785 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 58,581 psi | 90% | 2805 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 57,290 psi | 88% | 2890 fps | 99.3% |
| ADI AR 2209 | <<locked>> | 86% | 55,738 psi | 86% | 2818 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 90% | 58,015 psi | 89% | 2887 fps | 99.8% |
| ADI AR 2217 | <<locked>> | 98% | 56,405 psi | 87% | 2854 fps | 99.9% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 53,084 psi | 82% | 2894 fps | 97.5% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 55,042 psi | 85% | 2874 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 55,840 psi | 86% | 2808 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 55,303 psi | 85% | 2805 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 90% | 58,363 psi | 90% | 2881 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 56,130 psi | 86% | 2789 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 56,376 psi | 87% | 2854 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 56,869 psi | 88% | 2874 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 58,798 psi | 90% | 2946 fps | 98.5% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 49,966 psi | 77% | 2799 fps | 96.2% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 58,653 psi | 90% | 2844 fps | 98.5% |
| Bofors RP15 | <<locked>> | 92% | 57,522 psi | 89% | 2867 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 56,304 psi | 87% | 2871 fps | 99.9% |
| Bofors RP5 | <<locked>> | 90% | 58,363 psi | 90% | 2881 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 58,044 psi | 89% | 2877 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 57,101 psi | 88% | 2818 fps | 99.5% |
| Hodgdon H4831 SC | <<locked>> | 88% | 56,072 psi | 86% | 2805 fps | 99.4% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 56,014 psi | 86% | 2730 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 55,376 psi | 85% | 2936 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,550 psi | 58% | 1808 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 57,986 psi | 89% | 2792 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 55,100 psi | 85% | 2746 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 57,609 psi | 89% | 2802 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 90% | 56,130 psi | 86% | 2864 fps | 99.7% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 50,459 psi | 78% | 2795 fps | 99.4% |
| Lovex S065 | <<locked>> | 82% | 58,146 psi | 89% | 2769 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 56,768 psi | 87% | 2772 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,086 psi | 86% | 2756 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,666 psi | 86% | 2799 fps | 99.9% |
| Norma 217ᴾ | <<locked>> | 100% | 51,343 psi | 79% | 2822 fps | 100% |
| Norma MRP | <<locked>> | 88% | 58,566 psi | 90% | 2894 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,681 psi | 87% | 2789 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 57,508 psi | 89% | 2887 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 82% | 55,651 psi | 86% | 2795 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 56,043 psi | 86% | 2818 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,479 psi | 59% | 1850 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 57,493 psi | 88% | 2854 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 56,449 psi | 87% | 2927 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 55,695 psi | 86% | 2887 fps | 99.4% |
| Rottweil R 904 | <<locked>> | 86% | 56,376 psi | 87% | 2789 fps | 99.7% |
| Rottweil R 905 | <<locked>> | 86% | 54,984 psi | 85% | 2799 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 82% | 58,146 psi | 89% | 2769 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 56,768 psi | 87% | 2772 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,290 psi | 88% | 2726 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 58,450 psi | 90% | 2848 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 58,059 psi | 89% | 2779 fps | 99.5% |
| Somchem S365 | <<locked>> | 84% | 57,986 psi | 89% | 2789 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,434 psi | 85% | 2769 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 58,160 psi | 90% | 2776 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 55,434 psi | 85% | 2756 fps | 100% |
| Vihtavuori N170 | <<locked>> | 96% | 58,276 psi | 90% | 2822 fps | 96.8% |
| Vihtavuori N550 | <<locked>> | 82% | 57,522 psi | 89% | 2782 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 58,175 psi | 90% | 2818 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 58,015 psi | 89% | 2897 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 92% | 54,998 psi | 85% | 2831 fps | 99.5% |
| Vihtavuori N568 | <<locked>> | 96% | 56,260 psi | 87% | 2890 fps | 99.1% |
| Vihtavuori N570 | <<locked>> | 98% | 57,522 psi | 89% | 2949 fps | 98% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 57,769 psi | 89% | 2726 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 55,985 psi | 86% | 2874 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 55,390 psi | 85% | 2766 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% | 41,452 psi | 64% | 2530 fps | 99.7% |
| Accurate 4350 | <<locked>> | 80% | 54,636 psi | 84% | 2753 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 42,902 psi | 66% | 2644 fps | 96.5% |
| ADI AR 2209 | <<locked>> | 80% | 45,426 psi | 70% | 2654 fps | 99% |
| ADI AR 2213 | <<locked>> | 80% | 40,872 psi | 63% | 2595 fps | 97% |
| ADI AR 2217 | <<locked>> | 84% | 34,795 psi | 54% | 2454 fps | 95.2% |
| ADI AR 2218 | <<locked>> | 96% | 45,730 psi | 70% | 2753 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 82% | 29,718 psi | 46% | 2362 fps | 96.1% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,257 psi | 80% | 2759 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,368 psi | 70% | 2644 fps | 99% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,553 psi | 64% | 2602 fps | 98.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,176 psi | 62% | 2549 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,664 psi | 53% | 2484 fps | 99.3% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,353 psi | 70% | 2703 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 46,659 psi | 72% | 2749 fps | 95.8% |
| Alliant Reloder-50 | <<locked>> | 98% | 46,296 psi | 71% | 2733 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 84% | 45,324 psi | 70% | 2621 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 38,551 psi | 59% | 2536 fps | 97.4% |
| Bofors RP30 | <<locked>> | 82% | 34,606 psi | 53% | 2470 fps | 95.4% |
| Bofors RP5 | <<locked>> | 80% | 41,553 psi | 64% | 2602 fps | 98.4% |
| Hodgdon H1000 | <<locked>> | 80% | 33,054 psi | 51% | 2411 fps | 95.1% |
| Hodgdon H4831 | <<locked>> | 80% | 43,337 psi | 67% | 2592 fps | 97.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,714 psi | 66% | 2582 fps | 96.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,153 psi | 76% | 2641 fps | 100% |
| Hodgdon Retumbo | 75 gr | 80% | 33,968 psi | 52% | 2513 fps | 96.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,137 psi | 43% | 1621 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,082 psi | 79% | 2694 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 51,692 psi | 80% | 2700 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,498 psi | 68% | 2589 fps | 97.5% |
| IMR 7828 SSC | <<locked>> | 80% | 39,552 psi | 61% | 2575 fps | 96.7% |
| IMR 8133 Enduron | <<locked>> | 90% | 35,592 psi | 55% | 2510 fps | 95.7% |
| Lovex S065 | <<locked>> | 80% | 54,679 psi | 84% | 2723 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,156 psi | 82% | 2723 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,752 psi | 55% | 2415 fps | 98.8% |
| Norma 204 | <<locked>> | 80% | 52,040 psi | 80% | 2743 fps | 99.7% |
| Norma 217 | <<locked>> | 84% | 29,153 psi | 45% | 2362 fps | 95% |
| Norma MRP | <<locked>> | 80% | 44,019 psi | 68% | 2667 fps | 99.6% |
| Norma URP | <<locked>> | 80% | 52,982 psi | 82% | 2736 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,378 psi | 61% | 2582 fps | 97.1% |
| Ramshot Hunter | <<locked>> | 80% | 52,098 psi | 80% | 2746 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,462 psi | 55% | 2464 fps | 97.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,877 psi | 44% | 1660 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,447 psi | 82% | 2799 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 33,141 psi | 51% | 2484 fps | 97.7% |
| ReloadSwiss RS 80 | 86.9 gr | 86% | 37,840 psi | 58% | 2566 fps | 95% |
| Rottweil R 904 | <<locked>> | 80% | 46,427 psi | 71% | 2628 fps | 98.4% |
| Rottweil R 905 | <<locked>> | 80% | 45,049 psi | 69% | 2635 fps | 99% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,679 psi | 84% | 2723 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,156 psi | 82% | 2723 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,621 psi | 83% | 2677 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,701 psi | 69% | 2631 fps | 99% |
| Somchem S361 | <<locked>> | 80% | 47,384 psi | 73% | 2615 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 50,633 psi | 78% | 2694 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,571 psi | 70% | 2615 fps | 99.5% |
| Vihtavuori N160 | <<locked>> | 80% | 54,389 psi | 84% | 2726 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,595 psi | 61% | 2493 fps | 98.3% |
| Vihtavuori N170 | <<locked>> | 92% | 51,010 psi | 79% | 2710 fps | 95.2% |
| Vihtavuori N550 | <<locked>> | 80% | 53,882 psi | 83% | 2733 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,744 psi | 69% | 2621 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,787 psi | 67% | 2661 fps | 97.4% |
| Vihtavuori N565 | <<locked>> | 80% | 36,289 psi | 56% | 2487 fps | 95.2% |
| Vihtavuori N568 | <<locked>> | 88% | 42,119 psi | 65% | 2648 fps | 95.9% |
| Vihtavuori N570 | 89.5 gr | 92% | 46,238 psi | 71% | 2759 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,896 psi | 83% | 2677 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 38,014 psi | 59% | 2598 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,771 psi | 64% | 2546 fps | 98.4% |
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 72 powders for .300 Rem. Ultra Mag. loaded with the .308 | 190gr | Sierra MatchKing. Vihtavuori N570 delivers the highest muzzle velocity at 2,949 fps; across all powders the maximum-charge window runs from 1,808 fps to 2,949 fps. Accurate 8700 gives the best case fill at 100 %, and 72 of the 72 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 190.0 gr projectile in 0.308" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2218, ADI AR 2225 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 80, Vihtavuori N570 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 190gr | Sierra MatchKing they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 8700, IMR 7977 Enduron, Lovex D100 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.