Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 170gr | Speer Deep Curl Flat Points bullet and 70 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% | 55,405 psi | 85% | 2871 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 55,898 psi | 86% | 2904 fps | 100% |
| Accurate MAGPRO | <<locked>> | 90% | 58,363 psi | 90% | 3028 fps | 98.9% |
| ADI AR 2209 | <<locked>> | 88% | 56,942 psi | 88% | 2963 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 90% | 55,114 psi | 85% | 2969 fps | 99.1% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 57,493 psi | 88% | 2992 fps | 99.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 51,895 psi | 80% | 2949 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 56,898 psi | 88% | 2959 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 56,405 psi | 87% | 2949 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 90% | 55,521 psi | 85% | 2963 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 92% | 56,971 psi | 88% | 2933 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 57,145 psi | 88% | 2995 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 57,914 psi | 89% | 3018 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 55,230 psi | 85% | 3009 fps | 97% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 56,101 psi | 86% | 2920 fps | 97.2% |
| Bofors RP15 | <<locked>> | 94% | 58,450 psi | 90% | 3005 fps | 99.9% |
| Bofors RP30 | <<locked>> | 98% | 56,956 psi | 88% | 3002 fps | 99.6% |
| Bofors RP5 | <<locked>> | 90% | 55,521 psi | 85% | 2963 fps | 99.8% |
| Bofors RP7 | <<locked>> | 82% | 57,159 psi | 88% | 2900 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 55,100 psi | 85% | 2956 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 82% | 57,261 psi | 88% | 2953 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 58,363 psi | 90% | 2959 fps | 99.1% |
| Hodgdon H4831 SC | <<locked>> | 90% | 57,319 psi | 88% | 2946 fps | 99% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 57,072 psi | 88% | 2877 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 55,985 psi | 86% | 3074 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 58,407 psi | 90% | 2989 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,376 psi | 58% | 1909 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 55,637 psi | 86% | 2887 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 82% | 58,494 psi | 90% | 2920 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 56,260 psi | 87% | 2894 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 55,274 psi | 85% | 2887 fps | 98.8% |
| IMR 7828 SSC | <<locked>> | 92% | 57,058 psi | 88% | 3005 fps | 99.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 47,297 psi | 73% | 2858 fps | 98.3% |
| Lovex S065 | <<locked>> | 82% | 56,043 psi | 86% | 2871 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 57,928 psi | 89% | 2920 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 56,971 psi | 88% | 2894 fps | 100% |
| Norma 204 | <<locked>> | 84% | 57,000 psi | 88% | 2943 fps | 99.7% |
| Norma 217ᴾ | <<locked>> | 100% | 47,906 psi | 74% | 2884 fps | 99.7% |
| Norma MRP | <<locked>> | 88% | 55,535 psi | 85% | 2982 fps | 100% |
| Norma URP | <<locked>> | 84% | 57,754 psi | 89% | 2936 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 58,407 psi | 90% | 3025 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 84% | 56,826 psi | 87% | 2940 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 57,145 psi | 88% | 2956 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,232 psi | 59% | 1952 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 56,014 psi | 86% | 2920 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 58,653 psi | 90% | 3002 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 57,261 psi | 88% | 3064 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 56,797 psi | 87% | 3022 fps | 98.9% |
| Rottweil R 904 | <<locked>> | 88% | 57,566 psi | 89% | 2930 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 88% | 56,130 psi | 86% | 2943 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 82% | 57,159 psi | 88% | 2900 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 56,043 psi | 86% | 2871 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 57,928 psi | 89% | 2920 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 54,955 psi | 85% | 2822 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 55,724 psi | 86% | 2936 fps | 99.7% |
| Somchem S361 | <<locked>> | 86% | 55,637 psi | 86% | 2864 fps | 98.7% |
| Somchem S365 | <<locked>> | 84% | 55,129 psi | 85% | 2887 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 56,492 psi | 87% | 2910 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 55,695 psi | 86% | 2877 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 56,333 psi | 87% | 2890 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 84% | 58,682 psi | 90% | 2930 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 55,361 psi | 85% | 2913 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 55,071 psi | 85% | 2976 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 94% | 55,695 psi | 86% | 2959 fps | 99.1% |
| Vihtavuori N568 | <<locked>> | 98% | 57,203 psi | 88% | 3025 fps | 98.6% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 58,305 psi | 90% | 3081 fps | 97.2% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 55,216 psi | 85% | 2822 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 57,450 psi | 88% | 2956 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 56,434 psi | 87% | 3012 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 56,550 psi | 87% | 2907 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% | 39,276 psi | 60% | 2598 fps | 98.9% |
| Accurate 4350 | <<locked>> | 80% | 52,011 psi | 80% | 2848 fps | 100% |
| Accurate MAGPRO | <<locked>> | 82% | 43,656 psi | 67% | 2769 fps | 95.6% |
| ADI AR 2209 | <<locked>> | 80% | 43,221 psi | 67% | 2726 fps | 97.8% |
| ADI AR 2213 | <<locked>> | 80% | 38,740 psi | 60% | 2657 fps | 95.1% |
| ADI AR 2217 | <<locked>> | 88% | 37,855 psi | 58% | 2628 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 86% | 32,126 psi | 49% | 2530 fps | 96% |
| Alliant Reloder-16 | <<locked>> | 80% | 49,588 psi | 76% | 2851 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 43,207 psi | 66% | 2720 fps | 97.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 39,276 psi | 60% | 2667 fps | 96.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 37,971 psi | 58% | 2625 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 32,750 psi | 50% | 2539 fps | 97.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 42,656 psi | 66% | 2776 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 51,184 psi | 79% | 2940 fps | 96% |
| Baschieri & Pellagri 109 | <<locked>> | 88% | 49,472 psi | 76% | 2808 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 36,477 psi | 56% | 2602 fps | 95.6% |
| Bofors RP30 | <<locked>> | 86% | 37,478 psi | 58% | 2641 fps | 95.3% |
| Bofors RP5 | <<locked>> | 80% | 39,276 psi | 60% | 2667 fps | 96.8% |
| Bofors RP7 | <<locked>> | 80% | 53,563 psi | 82% | 2848 fps | 99.8% |
| Hodgdon H1000 | <<locked>> | 84% | 36,027 psi | 55% | 2589 fps | 95.1% |
| Hodgdon H414 | <<locked>> | 80% | 53,447 psi | 82% | 2897 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 41,336 psi | 64% | 2664 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 80% | 40,596 psi | 62% | 2648 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 46,731 psi | 72% | 2730 fps | 100% |
| Hodgdon Retumbo | 79 gr | 82% | 34,316 psi | 53% | 2625 fps | 95.5% |
| Hodgdon Superformance | <<locked>> | 80% | 54,230 psi | 83% | 2930 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,949 psi | 43% | 1713 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 48,950 psi | 75% | 2779 fps | 99.5% |
| IMR 4451 Enduron | <<locked>> | 80% | 54,882 psi | 84% | 2867 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 49,139 psi | 76% | 2789 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 42,612 psi | 66% | 2664 fps | 96% |
| IMR 7828 SSC | <<locked>> | 82% | 40,118 psi | 62% | 2697 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 94% | 38,392 psi | 59% | 2677 fps | 95.6% |
| Lovex S065 | <<locked>> | 80% | 52,562 psi | 81% | 2818 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 50,981 psi | 78% | 2815 fps | 99.9% |
| Lovex S071 | <<locked>> | 80% | 33,794 psi | 52% | 2477 fps | 97.4% |
| Norma 204 | <<locked>> | 80% | 49,588 psi | 76% | 2825 fps | 98.9% |
| Norma 217 | <<locked>> | 90% | 33,562 psi | 52% | 2582 fps | 96% |
| Norma MRP | <<locked>> | 80% | 41,539 psi | 64% | 2736 fps | 98.6% |
| Norma URP | <<locked>> | 80% | 50,604 psi | 78% | 2831 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 37,144 psi | 57% | 2638 fps | 95% |
| Ramshot Hunter | <<locked>> | 80% | 49,545 psi | 76% | 2828 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 33,359 psi | 51% | 2520 fps | 95.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,631 psi | 44% | 1752 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 52,257 psi | 80% | 2864 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 50,589 psi | 78% | 2887 fps | 100% |
| ReloadSwiss RS 76 | 82.5 gr | 80% | 31,285 psi | 48% | 2530 fps | 95.3% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 41,379 psi | 64% | 2749 fps | 95.2% |
| Rottweil R 904 | <<locked>> | 80% | 44,382 psi | 68% | 2707 fps | 97% |
| Rottweil R 905 | <<locked>> | 80% | 42,801 psi | 66% | 2710 fps | 97.8% |
| Rottweil R 907 | <<locked>> | 80% | 53,563 psi | 82% | 2848 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 52,562 psi | 81% | 2818 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 50,981 psi | 78% | 2815 fps | 99.9% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 51,474 psi | 79% | 2769 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 42,467 psi | 65% | 2707 fps | 97.7% |
| Somchem S361 | <<locked>> | 80% | 45,281 psi | 70% | 2687 fps | 96.6% |
| Somchem S365 | <<locked>> | 80% | 48,051 psi | 74% | 2782 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 43,323 psi | 67% | 2690 fps | 98.6% |
| Vihtavuori N160 | <<locked>> | 80% | 51,982 psi | 80% | 2822 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 37,579 psi | 58% | 2562 fps | 96.9% |
| Vihtavuori N550 | <<locked>> | 80% | 51,445 psi | 79% | 2825 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 42,264 psi | 65% | 2700 fps | 100% |
| Vihtavuori N560 | 80 gr | 80% | 41,423 psi | 64% | 2726 fps | 95.6% |
| Vihtavuori N565 | <<locked>> | 84% | 39,407 psi | 61% | 2664 fps | 95.2% |
| Vihtavuori N568 | <<locked>> | 92% | 45,905 psi | 71% | 2831 fps | 96% |
| Vihtavuori N570 | <<locked>> | 96% | 50,285 psi | 77% | 2946 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 51,590 psi | 79% | 2772 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 53,635 psi | 83% | 2900 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 35,027 psi | 54% | 2657 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 39,784 psi | 61% | 2615 fps | 96.9% |
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 76 powders for .300 Rem. Ultra Mag. loaded with the .308 | 170gr | Speer Deep Curl Flat Points. Vihtavuori N570 delivers the highest muzzle velocity at 3,081 fps; across all powders the maximum-charge window runs from 1,909 fps to 3,081 fps. ADI AR 2217 gives the best case fill at 100 %, and 76 of the 76 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 1:14.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, 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 76, Vihtavuori N560 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 170gr | Speer Deep Curl Flat Points 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.