Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 200gr | Speer Grand Slam bullet and 56 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 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>> | 88% | 57,667 psi | 89% | 2717 fps | 100% |
| Accurate MAGPRO | <<locked>> | 86% | 56,594 psi | 87% | 2818 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 84% | 55,013 psi | 85% | 2749 fps | 100% |
| ADI AR 2213 | <<locked>> | 88% | 57,319 psi | 88% | 2818 fps | 99.9% |
| ADI AR 2217 | <<locked>> | 96% | 56,159 psi | 86% | 2792 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 56,623 psi | 87% | 2904 fps | 98.8% |
| ADI AR 2225 | <<locked>> | 98% | 55,143 psi | 85% | 2815 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 55,187 psi | 85% | 2746 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 55,187 psi | 85% | 2746 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 58,291 psi | 90% | 2789 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 88% | 57,769 psi | 89% | 2808 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 88% | 55,898 psi | 86% | 2723 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 92% | 56,188 psi | 86% | 2789 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 84% | 56,623 psi | 87% | 2805 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 58,552 psi | 90% | 2884 fps | 98.9% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 54,099 psi | 83% | 2808 fps | 97.7% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 57,725 psi | 89% | 2776 fps | 98.8% |
| Bofors RP15 | <<locked>> | 90% | 57,145 psi | 88% | 2802 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 56,086 psi | 86% | 2805 fps | 100% |
| Bofors RP5 | <<locked>> | 88% | 57,769 psi | 89% | 2808 fps | 100% |
| Hodgdon H1000 | <<locked>> | 94% | 57,798 psi | 89% | 2815 fps | 100% |
| Hodgdon H4831 | <<locked>> | 86% | 56,260 psi | 87% | 2749 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 86% | 55,303 psi | 85% | 2736 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 55,347 psi | 85% | 2661 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 92% | 55,434 psi | 85% | 2871 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,666 psi | 58% | 1772 fps | 100% |
| IMR 4350 | <<locked>> | 82% | 57,145 psi | 88% | 2723 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 57,943 psi | 89% | 2723 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 56,681 psi | 87% | 2733 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 88% | 55,796 psi | 86% | 2802 fps | 99.9% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 54,114 psi | 83% | 2792 fps | 99.9% |
| Lovex S071 | <<locked>> | 92% | 55,680 psi | 86% | 2690 fps | 100% |
| Norma 204 | <<locked>> | 82% | 58,494 psi | 90% | 2779 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 55,303 psi | 85% | 2812 fps | 100% |
| Norma MRP | <<locked>> | 86% | 57,870 psi | 89% | 2822 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 57,043 psi | 88% | 2818 fps | 100% |
| Ramshot Hunter | <<locked>> | 82% | 58,508 psi | 90% | 2772 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 55,463 psi | 85% | 2749 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,783 psi | 60% | 1818 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 92% | 56,260 psi | 87% | 2858 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 55,550 psi | 85% | 2828 fps | 99.6% |
| Rottweil R 904 | <<locked>> | 84% | 55,564 psi | 86% | 2720 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 86% | 58,160 psi | 90% | 2785 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 57,769 psi | 89% | 2779 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 56,971 psi | 88% | 2710 fps | 99.7% |
| Somchem S365 | <<locked>> | 82% | 57,493 psi | 88% | 2717 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 58,479 psi | 90% | 2753 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 58,450 psi | 90% | 2736 fps | 100% |
| Vihtavuori N170 | <<locked>> | 94% | 57,827 psi | 89% | 2762 fps | 97.4% |
| Vihtavuori N555 | <<locked>> | 86% | 57,711 psi | 89% | 2746 fps | 100% |
| Vihtavuori N560 | <<locked>> | 86% | 57,246 psi | 88% | 2828 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 92% | 58,508 psi | 90% | 2822 fps | 99.9% |
| Vihtavuori N568 | <<locked>> | 94% | 56,057 psi | 86% | 2828 fps | 99.4% |
| Vihtavuori N570 | <<locked>> | 96% | 57,363 psi | 88% | 2890 fps | 98.4% |
| Winchester StaBALL HD | <<locked>> | 88% | 56,072 psi | 86% | 2805 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 58,407 psi | 90% | 2749 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% | 44,005 psi | 68% | 2516 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 45,759 psi | 70% | 2641 fps | 97.9% |
| ADI AR 2209 | <<locked>> | 80% | 48,051 psi | 74% | 2641 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 80% | 43,236 psi | 67% | 2585 fps | 98.2% |
| ADI AR 2217 | <<locked>> | 82% | 34,606 psi | 53% | 2402 fps | 95.9% |
| ADI AR 2218 | <<locked>> | 94% | 45,411 psi | 70% | 2700 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 29,617 psi | 46% | 2313 fps | 96.8% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 48,356 psi | 74% | 2641 fps | 99.7% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 48,356 psi | 74% | 2641 fps | 99.7% |
| Alliant Reloder-19 | <<locked>> | 80% | 47,921 psi | 74% | 2635 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 43,990 psi | 68% | 2592 fps | 99.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 42,844 psi | 66% | 2533 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 37,072 psi | 57% | 2480 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 48,718 psi | 75% | 2694 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 43,265 psi | 67% | 2628 fps | 95.4% |
| Alliant Reloder-50 | <<locked>> | 96% | 46,485 psi | 72% | 2680 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 41,756 psi | 64% | 2503 fps | 95% |
| Bofors RP15 | <<locked>> | 80% | 41,002 psi | 63% | 2533 fps | 98.6% |
| Bofors RP30 | <<locked>> | 80% | 34,592 psi | 53% | 2415 fps | 96.1% |
| Bofors RP5 | <<locked>> | 80% | 43,990 psi | 68% | 2592 fps | 99.2% |
| Hodgdon H1000 | <<locked>> | 80% | 35,143 psi | 54% | 2415 fps | 96.8% |
| Hodgdon H4831 | <<locked>> | 80% | 45,803 psi | 70% | 2585 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 80% | 44,991 psi | 69% | 2569 fps | 98% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 51,735 psi | 80% | 2615 fps | 100% |
| Hodgdon Retumbo | 76.2 gr | 80% | 36,172 psi | 56% | 2520 fps | 98.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,253 psi | 43% | 1588 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 53,606 psi | 83% | 2674 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 54,317 psi | 84% | 2674 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 46,746 psi | 72% | 2575 fps | 98.5% |
| IMR 7828 SSC | <<locked>> | 80% | 41,974 psi | 65% | 2569 fps | 98% |
| IMR 8133 Enduron | <<locked>> | 86% | 33,388 psi | 51% | 2405 fps | 95.4% |
| Lovex S071 | <<locked>> | 80% | 37,956 psi | 58% | 2405 fps | 99.5% |
| Norma 204 | <<locked>> | 80% | 54,752 psi | 84% | 2726 fps | 100% |
| Norma 217 | <<locked>> | 82% | 29,254 psi | 45% | 2316 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 46,847 psi | 72% | 2657 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 42,293 psi | 65% | 2585 fps | 98.4% |
| Ramshot Hunter | <<locked>> | 80% | 54,853 psi | 84% | 2723 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,029 psi | 59% | 2467 fps | 98.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,008 psi | 45% | 1627 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 35,607 psi | 55% | 2497 fps | 99.1% |
| ReloadSwiss RS 80 | 86.4 gr | 84% | 38,014 psi | 59% | 2516 fps | 95.8% |
| Rottweil R 904 | <<locked>> | 80% | 48,689 psi | 75% | 2612 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 80% | 47,514 psi | 73% | 2625 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 47,181 psi | 73% | 2618 fps | 99.6% |
| Somchem S361 | <<locked>> | 80% | 49,893 psi | 77% | 2605 fps | 98.9% |
| Somchem S365 | <<locked>> | 80% | 53,708 psi | 83% | 2671 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 47,935 psi | 74% | 2598 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 80% | 41,945 psi | 65% | 2487 fps | 99.2% |
| Vihtavuori N170 | <<locked>> | 90% | 50,401 psi | 78% | 2648 fps | 95.7% |
| Vihtavuori N555 | <<locked>> | 80% | 47,413 psi | 73% | 2605 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 46,470 psi | 72% | 2654 fps | 98.5% |
| Vihtavuori N565 | <<locked>> | 80% | 38,725 psi | 60% | 2484 fps | 96.7% |
| Vihtavuori N568 | <<locked>> | 84% | 39,146 psi | 60% | 2530 fps | 95.5% |
| Vihtavuori N570 | 89 gr | 90% | 46,180 psi | 71% | 2703 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 41,292 psi | 64% | 2592 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 44,193 psi | 68% | 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 56 powders for .300 Rem. Ultra Mag. loaded with the .308 | 200gr | Speer Grand Slam. ADI AR 2218 delivers the highest muzzle velocity at 2,904 fps; across all powders the maximum-charge window runs from 1,772 fps to 2,904 fps. ADI AR 2218 gives the best case fill at 100 %, and 56 of the 56 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 1:14.5 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, Vihtavuori N570, ReloadSwiss RS 80 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 200gr | Speer Grand Slam 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.