Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 170gr | Impala RNFP KO bullet and 64 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>> | 90% | 58,233 psi | 90% | 2897 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 58,494 psi | 90% | 2927 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 56,376 psi | 87% | 2986 fps | 98.5% |
| ADI AR 2209 | <<locked>> | 88% | 58,523 psi | 90% | 2976 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 90% | 56,637 psi | 87% | 2982 fps | 99.2% |
| ADI AR 2217 | <<locked>> | 98% | 55,274 psi | 85% | 2946 fps | 99.4% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 53,925 psi | 83% | 2972 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 58,595 psi | 90% | 2972 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 58,247 psi | 90% | 2966 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 90% | 57,363 psi | 88% | 2982 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 90% | 55,506 psi | 85% | 2904 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 55,187 psi | 85% | 2963 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 56,144 psi | 86% | 2986 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 57,305 psi | 88% | 3035 fps | 97.3% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 57,493 psi | 88% | 2933 fps | 97.3% |
| Bofors RP15 | <<locked>> | 92% | 56,826 psi | 87% | 2972 fps | 99.8% |
| Bofors RP30 | <<locked>> | 96% | 55,361 psi | 85% | 2969 fps | 99.4% |
| Bofors RP5 | <<locked>> | 90% | 57,363 psi | 88% | 2982 fps | 99.8% |
| Hodgdon H1000 | <<locked>> | 96% | 56,782 psi | 87% | 2972 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 88% | 56,275 psi | 87% | 2920 fps | 98.7% |
| Hodgdon H4831 SC | <<locked>> | 88% | 55,332 psi | 85% | 2904 fps | 98.6% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 55,579 psi | 86% | 2848 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 57,769 psi | 89% | 3094 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,608 psi | 58% | 1900 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 57,435 psi | 88% | 2900 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 58,378 psi | 90% | 2910 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 56,782 psi | 87% | 2900 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 90% | 55,056 psi | 85% | 2963 fps | 99.1% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,821 psi | 77% | 2894 fps | 98.7% |
| Lovex S065 | <<locked>> | 82% | 58,044 psi | 89% | 2884 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 56,536 psi | 87% | 2884 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,260 psi | 87% | 2871 fps | 100% |
| Norma 204 | <<locked>> | 84% | 58,784 psi | 90% | 2959 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 50,575 psi | 78% | 2923 fps | 99.9% |
| Norma MRP | <<locked>> | 88% | 57,522 psi | 89% | 3002 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,159 psi | 86% | 2904 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 56,159 psi | 86% | 2986 fps | 99.5% |
| Ramshot Hunter | <<locked>> | 84% | 58,740 psi | 90% | 2956 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 55,027 psi | 85% | 2920 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,566 psi | 59% | 1942 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 58,378 psi | 90% | 2940 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 56,318 psi | 87% | 2963 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 55,100 psi | 85% | 3028 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 54,911 psi | 85% | 2986 fps | 98.6% |
| Rottweil R 904 | <<locked>> | 86% | 55,608 psi | 86% | 2887 fps | 99.1% |
| Rottweil R 905 | <<locked>> | 88% | 58,001 psi | 89% | 2956 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 82% | 58,044 psi | 89% | 2884 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 56,536 psi | 87% | 2884 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,043 psi | 88% | 2835 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 57,609 psi | 89% | 2953 fps | 99.8% |
| Somchem S361 | <<locked>> | 86% | 57,319 psi | 88% | 2874 fps | 98.8% |
| Somchem S365 | <<locked>> | 84% | 57,493 psi | 88% | 2907 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,259 psi | 85% | 2877 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 82% | 57,522 psi | 89% | 2887 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 58,334 psi | 90% | 2907 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 57,101 psi | 88% | 2897 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 57,841 psi | 89% | 2933 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 56,913 psi | 88% | 2999 fps | 99% |
| Vihtavuori N565 | <<locked>> | 94% | 58,262 psi | 90% | 2989 fps | 99.3% |
| Vihtavuori N568 | <<locked>> | 96% | 55,187 psi | 85% | 2986 fps | 98.1% |
| Vihtavuori N570 | <<locked>> | 98% | 56,217 psi | 87% | 3041 fps | 96.6% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 57,072 psi | 88% | 2835 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 58,798 psi | 90% | 3038 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 58,552 psi | 90% | 2923 fps | 99.8% |
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% | 42,409 psi | 65% | 2648 fps | 99.4% |
| Accurate 4350 | <<locked>> | 80% | 54,940 psi | 85% | 2874 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 43,004 psi | 66% | 2746 fps | 95.3% |
| ADI AR 2209 | <<locked>> | 80% | 45,194 psi | 70% | 2753 fps | 98.1% |
| ADI AR 2213 | <<locked>> | 80% | 40,741 psi | 63% | 2690 fps | 95.8% |
| ADI AR 2217 | <<locked>> | 88% | 40,001 psi | 62% | 2664 fps | 95.9% |
| ADI AR 2225 | <<locked>> | 82% | 30,603 psi | 47% | 2470 fps | 95% |
| Alliant Reloder-16 | <<locked>> | 80% | 51,488 psi | 79% | 2867 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,310 psi | 70% | 2749 fps | 98.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,597 psi | 64% | 2703 fps | 97.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,277 psi | 62% | 2661 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,157 psi | 54% | 2592 fps | 98.7% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,252 psi | 70% | 2815 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 49,719 psi | 77% | 2907 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 50,894 psi | 78% | 2822 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 38,870 psi | 60% | 2644 fps | 96.5% |
| Bofors RP30 | <<locked>> | 84% | 37,449 psi | 58% | 2635 fps | 95.3% |
| Bofors RP5 | <<locked>> | 80% | 41,597 psi | 64% | 2703 fps | 97.4% |
| Hodgdon H1000 | <<locked>> | 84% | 38,145 psi | 59% | 2625 fps | 95.9% |
| Hodgdon H4831 | <<locked>> | 80% | 43,337 psi | 67% | 2694 fps | 95.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,583 psi | 66% | 2677 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,907 psi | 75% | 2749 fps | 100% |
| Hodgdon Retumbo | 75.3 gr | 80% | 34,360 psi | 53% | 2615 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,311 psi | 44% | 1706 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,865 psi | 78% | 2799 fps | 99.6% |
| IMR 4831 | <<locked>> | 80% | 51,634 psi | 79% | 2815 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,498 psi | 68% | 2687 fps | 96.4% |
| IMR 7828 SSC | <<locked>> | 80% | 39,508 psi | 61% | 2671 fps | 95.4% |
| IMR 8133 Enduron | <<locked>> | 92% | 38,348 psi | 59% | 2671 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 54,592 psi | 84% | 2835 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,301 psi | 82% | 2835 fps | 99.9% |
| Lovex S071 | <<locked>> | 80% | 36,869 psi | 57% | 2533 fps | 98.3% |
| Norma 204 | <<locked>> | 80% | 51,474 psi | 79% | 2844 fps | 99.1% |
| Norma 217 | <<locked>> | 86% | 32,068 psi | 49% | 2533 fps | 95.2% |
| Norma MRP | <<locked>> | 80% | 43,859 psi | 68% | 2772 fps | 99% |
| Norma URP | <<locked>> | 80% | 52,823 psi | 81% | 2854 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,450 psi | 61% | 2680 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 51,605 psi | 79% | 2851 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,810 psi | 55% | 2569 fps | 96.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,066 psi | 45% | 1749 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,766 psi | 84% | 2890 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 52,678 psi | 81% | 2907 fps | 100% |
| ReloadSwiss RS 76 | 80.6 gr | 80% | 33,808 psi | 52% | 2592 fps | 96.7% |
| ReloadSwiss RS 80 | 91.4 gr | 90% | 44,048 psi | 68% | 2799 fps | 96.1% |
| Rottweil R 904 | <<locked>> | 80% | 46,195 psi | 71% | 2726 fps | 97.4% |
| Rottweil R 905 | <<locked>> | 80% | 44,976 psi | 69% | 2743 fps | 98.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,592 psi | 84% | 2835 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,301 psi | 82% | 2835 fps | 99.9% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,534 psi | 82% | 2785 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,628 psi | 69% | 2736 fps | 98.2% |
| Somchem S361 | <<locked>> | 80% | 47,442 psi | 73% | 2717 fps | 97.1% |
| Somchem S365 | <<locked>> | 80% | 50,575 psi | 78% | 2812 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,730 psi | 70% | 2723 fps | 99% |
| Vihtavuori N160 | <<locked>> | 80% | 54,128 psi | 83% | 2841 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,929 psi | 61% | 2598 fps | 97.5% |
| Vihtavuori N550 | <<locked>> | 80% | 53,635 psi | 83% | 2844 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,121 psi | 69% | 2740 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,540 psi | 67% | 2759 fps | 96.2% |
| Vihtavuori N565 | <<locked>> | 82% | 39,378 psi | 61% | 2651 fps | 95.1% |
| Vihtavuori N568 | <<locked>> | 90% | 44,933 psi | 69% | 2805 fps | 95.6% |
| Vihtavuori N570 | <<locked>> | 96% | 52,533 psi | 81% | 2979 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,388 psi | 82% | 2789 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,681 psi | 58% | 2713 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,989 psi | 65% | 2648 fps | 97.5% |
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 71 powders for .300 Rem. Ultra Mag. loaded with the .308 | 170gr | Impala RNFP KO. Hodgdon Retumbo delivers the highest muzzle velocity at 3,094 fps; across all powders the maximum-charge window runs from 1,900 fps to 3,094 fps. ADI AR 2218 gives the best case fill at 100 %, and 71 of the 71 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 170.0 gr projectile in 0.308" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, Alliant Reloder-33 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 | 170gr | Impala RNFP KO they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-50, 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.