Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 165gr | Barnes X FN 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 Vihtavuori N560.
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% | 58,436 psi | 90% | 2936 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 58,566 psi | 90% | 2963 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 56,637 psi | 87% | 3022 fps | 98.4% |
| ADI AR 2209 | <<locked>> | 88% | 58,595 psi | 90% | 3012 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 90% | 56,840 psi | 87% | 3018 fps | 99.2% |
| ADI AR 2217 | <<locked>> | 98% | 55,463 psi | 85% | 2982 fps | 99.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,244 psi | 83% | 3012 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 58,682 psi | 90% | 3009 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 58,363 psi | 90% | 3002 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 90% | 57,566 psi | 89% | 3022 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 90% | 55,608 psi | 86% | 2940 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 55,347 psi | 85% | 2999 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 56,289 psi | 87% | 3025 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 57,624 psi | 89% | 3068 fps | 97.2% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 57,638 psi | 89% | 2969 fps | 97.2% |
| Bofors RP15 | <<locked>> | 92% | 56,811 psi | 87% | 3005 fps | 99.7% |
| Bofors RP30 | <<locked>> | 96% | 55,622 psi | 86% | 3005 fps | 99.4% |
| Bofors RP5 | <<locked>> | 90% | 57,566 psi | 89% | 3022 fps | 99.8% |
| Hodgdon H1000 | <<locked>> | 96% | 56,971 psi | 88% | 3009 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 88% | 56,347 psi | 87% | 2953 fps | 98.6% |
| Hodgdon H4831 SC | <<locked>> | 88% | 55,347 psi | 85% | 2936 fps | 98.5% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 55,463 psi | 85% | 2881 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 58,001 psi | 89% | 3130 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,666 psi | 58% | 1932 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 57,435 psi | 88% | 2936 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 58,436 psi | 90% | 2946 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 56,840 psi | 87% | 2936 fps | 98.8% |
| IMR 7828 SSC | <<locked>> | 90% | 55,259 psi | 85% | 3002 fps | 99% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,966 psi | 77% | 2930 fps | 98.6% |
| Lovex S065 | <<locked>> | 82% | 57,986 psi | 89% | 2920 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 56,608 psi | 87% | 2923 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 56,333 psi | 87% | 2907 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,100 psi | 85% | 2936 fps | 99.4% |
| Norma 217ᴾ | <<locked>> | 100% | 50,734 psi | 78% | 2956 fps | 99.8% |
| Norma MRP | <<locked>> | 88% | 57,696 psi | 89% | 3038 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,275 psi | 87% | 2940 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 56,231 psi | 87% | 3022 fps | 99.4% |
| Ramshot Hunter | <<locked>> | 82% | 55,143 psi | 85% | 2940 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 55,230 psi | 85% | 2956 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,580 psi | 59% | 1978 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 58,465 psi | 90% | 2979 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 56,623 psi | 87% | 3002 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 55,187 psi | 85% | 3061 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 55,071 psi | 85% | 3022 fps | 98.5% |
| Rottweil R 904 | <<locked>> | 86% | 55,782 psi | 86% | 2927 fps | 99% |
| Rottweil R 905 | <<locked>> | 88% | 58,117 psi | 89% | 2995 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 82% | 57,986 psi | 89% | 2920 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 56,608 psi | 87% | 2923 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 57,087 psi | 88% | 2874 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 57,696 psi | 89% | 2989 fps | 99.8% |
| Somchem S361 | <<locked>> | 86% | 57,464 psi | 88% | 2910 fps | 98.7% |
| Somchem S365 | <<locked>> | 84% | 57,508 psi | 89% | 2943 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 55,361 psi | 85% | 2917 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 82% | 57,595 psi | 89% | 2927 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 58,465 psi | 90% | 2943 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 82% | 57,276 psi | 88% | 2936 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 57,957 psi | 89% | 2972 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 57,072 psi | 88% | 3035 fps | 98.9% |
| Vihtavuori N565 | <<locked>> | 94% | 58,479 psi | 90% | 3028 fps | 99.2% |
| Vihtavuori N568 | <<locked>> | 96% | 55,521 psi | 85% | 3025 fps | 98.1% |
| Vihtavuori N570 | <<locked>> | 98% | 56,463 psi | 87% | 3077 fps | 96.5% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 57,101 psi | 88% | 2871 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 54,926 psi | 85% | 3025 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 58,682 psi | 90% | 2959 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% | 42,366 psi | 65% | 2677 fps | 99.3% |
| Accurate 4350 | <<locked>> | 80% | 54,897 psi | 84% | 2910 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 43,149 psi | 66% | 2779 fps | 95.1% |
| ADI AR 2209 | <<locked>> | 80% | 45,194 psi | 70% | 2785 fps | 98% |
| ADI AR 2213 | <<locked>> | 80% | 40,843 psi | 63% | 2723 fps | 95.5% |
| ADI AR 2217 | <<locked>> | 88% | 40,074 psi | 62% | 2697 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 84% | 32,561 psi | 50% | 2556 fps | 95.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 51,503 psi | 79% | 2904 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,252 psi | 70% | 2782 fps | 98% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,640 psi | 64% | 2736 fps | 97.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,408 psi | 62% | 2697 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,143 psi | 54% | 2621 fps | 98.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,411 psi | 70% | 2851 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 96% | 49,908 psi | 77% | 2940 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 51,111 psi | 79% | 2854 fps | 95.6% |
| Bofors RP15 | <<locked>> | 80% | 38,885 psi | 60% | 2677 fps | 96.2% |
| Bofors RP30 | <<locked>> | 84% | 37,594 psi | 58% | 2667 fps | 95.1% |
| Bofors RP5 | <<locked>> | 80% | 41,640 psi | 64% | 2736 fps | 97.3% |
| Hodgdon H1000 | <<locked>> | 84% | 38,145 psi | 59% | 2654 fps | 95.7% |
| Hodgdon H4831 | <<locked>> | 80% | 43,381 psi | 67% | 2726 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,685 psi | 66% | 2710 fps | 95.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,907 psi | 75% | 2785 fps | 100% |
| Hodgdon Retumbo | 76.9 gr | 80% | 34,432 psi | 53% | 2644 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,398 psi | 44% | 1739 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,792 psi | 78% | 2831 fps | 99.5% |
| IMR 4831 | <<locked>> | 80% | 51,561 psi | 79% | 2848 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,483 psi | 68% | 2720 fps | 96.3% |
| IMR 7828 SSC | <<locked>> | 80% | 39,639 psi | 61% | 2707 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 92% | 38,522 psi | 59% | 2700 fps | 95.3% |
| Lovex S065 | <<locked>> | 80% | 54,752 psi | 84% | 2874 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,272 psi | 82% | 2871 fps | 99.9% |
| Lovex S071 | <<locked>> | 80% | 36,941 psi | 57% | 2566 fps | 98.2% |
| Norma 204 | <<locked>> | 80% | 51,503 psi | 79% | 2881 fps | 99% |
| Norma 217 | <<locked>> | 88% | 34,171 psi | 53% | 2618 fps | 96% |
| Norma MRP | <<locked>> | 80% | 44,034 psi | 68% | 2808 fps | 98.9% |
| Norma URP | <<locked>> | 80% | 52,808 psi | 81% | 2887 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,523 psi | 61% | 2713 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 51,634 psi | 79% | 2887 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,940 psi | 55% | 2598 fps | 96.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,138 psi | 45% | 1778 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,752 psi | 84% | 2927 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 52,678 psi | 81% | 2943 fps | 100% |
| ReloadSwiss RS 76 | 82.3 gr | 80% | 33,866 psi | 52% | 2621 fps | 96.4% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 44,193 psi | 68% | 2828 fps | 95.9% |
| Rottweil R 904 | <<locked>> | 80% | 46,369 psi | 71% | 2762 fps | 97.3% |
| Rottweil R 905 | <<locked>> | 80% | 45,107 psi | 69% | 2776 fps | 98.1% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,752 psi | 84% | 2874 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,272 psi | 82% | 2871 fps | 99.9% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,664 psi | 83% | 2822 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,744 psi | 69% | 2769 fps | 98% |
| Somchem S361 | <<locked>> | 80% | 47,369 psi | 73% | 2746 fps | 96.9% |
| Somchem S365 | <<locked>> | 80% | 50,488 psi | 78% | 2844 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,832 psi | 71% | 2756 fps | 98.9% |
| Vihtavuori N160 | <<locked>> | 80% | 54,099 psi | 83% | 2877 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,900 psi | 61% | 2628 fps | 97.3% |
| Vihtavuori N550 | <<locked>> | 80% | 53,708 psi | 83% | 2884 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,136 psi | 69% | 2772 fps | 100% |
| Vihtavuori N560 | 79.8 gr | 80% | 43,700 psi | 67% | 2795 fps | 96% |
| Vihtavuori N565 | <<locked>> | 84% | 42,061 psi | 65% | 2740 fps | 95.8% |
| Vihtavuori N568 | <<locked>> | 90% | 45,121 psi | 69% | 2841 fps | 95.5% |
| Vihtavuori N570 | <<locked>> | 96% | 52,620 psi | 81% | 3015 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,534 psi | 82% | 2825 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,768 psi | 58% | 2743 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 42,047 psi | 65% | 2680 fps | 97.3% |
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 64 powders for .300 Rem. Ultra Mag. loaded with the .308 | 165gr | Barnes X FN. Hodgdon Retumbo delivers the highest muzzle velocity at 3,130 fps; across all powders the maximum-charge window runs from 1,932 fps to 3,130 fps. ADI AR 2225 gives the best case fill at 100 %, and 64 of the 64 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 165.0 gr projectile in 0.308" calls for a 1:14.0 twist; slower twists will usually not stabilise this weight. ADI AR 2225, Alliant Reloder-33, 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, Vihtavuori N560 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 165gr | Barnes X FN 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.