Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 150gr | Speer Boat-Tail bullet and 75 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Winchester StaBALL HD and ReloadSwiss RS 76.
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>> | 94% | 58,755 psi | 90% | 3061 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 55,332 psi | 85% | 3045 fps | 100% |
| Accurate High Country | <<locked>> | 90% | 56,376 psi | 87% | 3153 fps | 98.7% |
| Accurate MAGPRO | <<locked>> | 92% | 57,638 psi | 89% | 3153 fps | 97.9% |
| ADI AR 2209 | <<locked>> | 90% | 56,347 psi | 87% | 3094 fps | 99.2% |
| ADI AR 2213 | <<locked>> | 94% | 58,523 psi | 90% | 3159 fps | 98.9% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 52,692 psi | 81% | 3048 fps | 98.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 47,413 psi | 73% | 3005 fps | 99.6% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 56,652 psi | 87% | 3091 fps | 99.3% |
| Alliant Reloder-16 | <<locked>> | 86% | 56,260 psi | 87% | 3100 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 57,580 psi | 89% | 3114 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 55,985 psi | 86% | 3081 fps | 99.2% |
| Alliant Reloder-22 | <<locked>> | 94% | 58,653 psi | 90% | 3153 fps | 99.6% |
| Alliant Reloder-23 | <<locked>> | 94% | 56,057 psi | 86% | 3068 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 55,724 psi | 86% | 3127 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 56,811 psi | 87% | 3153 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 56,188 psi | 86% | 3045 fps | 96% |
| Bofors RP15 | <<locked>> | 96% | 57,580 psi | 89% | 3133 fps | 99.4% |
| Bofors RP30ᴾ | <<locked>> | 100% | 55,753 psi | 86% | 3120 fps | 98.9% |
| Bofors RP5 | <<locked>> | 94% | 58,653 psi | 90% | 3153 fps | 99.6% |
| Bofors RP7 | <<locked>> | 84% | 57,217 psi | 88% | 3045 fps | 99.7% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 58,334 psi | 90% | 3140 fps | 99.5% |
| Hodgdon H414 | <<locked>> | 84% | 56,913 psi | 88% | 3094 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 82% | 55,521 psi | 85% | 3048 fps | 99.2% |
| Hodgdon H4831 | <<locked>> | 92% | 58,088 psi | 89% | 3094 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 92% | 56,884 psi | 88% | 3074 fps | 98.1% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 56,550 psi | 87% | 3022 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 58,639 psi | 90% | 3258 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 58,044 psi | 89% | 3127 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,072 psi | 57% | 2018 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 55,579 psi | 86% | 3025 fps | 99.6% |
| IMR 4451 Enduron | <<locked>> | 84% | 58,566 psi | 90% | 3068 fps | 99.9% |
| IMR 4831 | <<locked>> | 86% | 55,724 psi | 86% | 3035 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 58,784 psi | 90% | 3074 fps | 98.5% |
| IMR 7828 SSC | <<locked>> | 94% | 56,304 psi | 87% | 3133 fps | 98.6% |
| Lovex S065 | <<locked>> | 84% | 55,970 psi | 86% | 3015 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 57,885 psi | 89% | 3064 fps | 99.9% |
| Lovex S071 | <<locked>> | 98% | 56,057 psi | 86% | 3022 fps | 100% |
| Norma 204 | <<locked>> | 86% | 56,927 psi | 88% | 3081 fps | 99.2% |
| Norma 217ᴾ | <<locked>> | 100% | 43,018 psi | 66% | 2923 fps | 98.2% |
| Norma MRP | <<locked>> | 92% | 58,697 psi | 90% | 3173 fps | 100% |
| Norma URP | <<locked>> | 86% | 57,493 psi | 88% | 3084 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 57,464 psi | 88% | 3153 fps | 99.1% |
| Ramshot Hunter | <<locked>> | 86% | 56,536 psi | 87% | 3081 fps | 100% |
| Ramshot Magnum | <<locked>> | 96% | 56,246 psi | 87% | 3081 fps | 99.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,840 psi | 58% | 2060 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 55,579 psi | 86% | 3061 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 58,204 psi | 90% | 3146 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 56,115 psi | 86% | 3192 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 55,448 psi | 85% | 3133 fps | 97.9% |
| Rottweil R 903 | <<locked>> | 82% | 58,726 psi | 90% | 3048 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 57,421 psi | 88% | 3064 fps | 98.6% |
| Rottweil R 905 | <<locked>> | 90% | 55,622 psi | 86% | 3074 fps | 99.2% |
| Rottweil R 907 | <<locked>> | 84% | 57,217 psi | 88% | 3045 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 84% | 55,970 psi | 86% | 3015 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 57,885 psi | 89% | 3064 fps | 99.9% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 58,059 psi | 89% | 2917 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 55,158 psi | 85% | 2963 fps | 99.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 55,201 psi | 85% | 3071 fps | 99.2% |
| Somchem S355 | <<locked>> | 82% | 58,305 psi | 90% | 3041 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 55,506 psi | 85% | 2989 fps | 97.8% |
| Somchem S365 | <<locked>> | 88% | 58,305 psi | 90% | 3081 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 56,188 psi | 86% | 3045 fps | 99.7% |
| Vihtavuori N150 | <<locked>> | 82% | 55,854 psi | 86% | 2956 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 55,361 psi | 85% | 3015 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 55,912 psi | 86% | 3018 fps | 99.5% |
| Vihtavuori N550 | <<locked>> | 86% | 58,581 psi | 90% | 3074 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 58,088 psi | 89% | 3100 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 58,305 psi | 90% | 3166 fps | 98.5% |
| Vihtavuori N565 | <<locked>> | 98% | 58,711 psi | 90% | 3143 fps | 98.8% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 55,912 psi | 86% | 3140 fps | 97.4% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 55,245 psi | 85% | 2966 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 57,130 psi | 88% | 3097 fps | 99.9% |
| Winchester StaBALL HD | <<locked>> | 94% | 54,737 psi | 84% | 3146 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 56,217 psi | 87% | 3035 fps | 99.2% |
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% | 36,114 psi | 56% | 2654 fps | 97.1% |
| Accurate 4350 | <<locked>> | 80% | 48,211 psi | 74% | 2930 fps | 100% |
| Accurate High Country | <<locked>> | 82% | 42,148 psi | 65% | 2884 fps | 95.1% |
| Accurate MAGPRO | <<locked>> | 86% | 46,282 psi | 71% | 2949 fps | 95.1% |
| ADI AR 2209 | <<locked>> | 80% | 39,929 psi | 61% | 2789 fps | 95.5% |
| ADI AR 2213 | <<locked>> | 86% | 44,164 psi | 68% | 2900 fps | 95.6% |
| ADI AR 2217 | <<locked>> | 94% | 42,815 psi | 66% | 2858 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 90% | 33,750 psi | 52% | 2684 fps | 95.2% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 40,495 psi | 62% | 2792 fps | 95.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 45,774 psi | 70% | 2933 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 53,447 psi | 82% | 3054 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 40,118 psi | 62% | 2782 fps | 95.6% |
| Alliant Reloder-22 | <<locked>> | 82% | 38,508 psi | 59% | 2776 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 34,563 psi | 53% | 2684 fps | 99.4% |
| Alliant Reloder-25 | <<locked>> | 80% | 30,008 psi | 46% | 2575 fps | 95% |
| Alliant Reloder-26 | <<locked>> | 80% | 38,522 psi | 59% | 2828 fps | 99% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 52,794 psi | 81% | 2989 fps | 95.1% |
| Bofors RP15 | <<locked>> | 86% | 41,162 psi | 63% | 2835 fps | 96% |
| Bofors RP30 | <<locked>> | 92% | 42,119 psi | 65% | 2874 fps | 95.8% |
| Bofors RP5 | <<locked>> | 82% | 38,508 psi | 59% | 2776 fps | 95.2% |
| Bofors RP7 | <<locked>> | 80% | 50,270 psi | 77% | 2930 fps | 99% |
| Hodgdon H1000 | <<locked>> | 90% | 40,930 psi | 63% | 2818 fps | 95.6% |
| Hodgdon H414 | <<locked>> | 80% | 49,748 psi | 77% | 2976 fps | 99.2% |
| Hodgdon H4350 | <<locked>> | 80% | 52,069 psi | 80% | 2992 fps | 98.8% |
| Hodgdon H4831 | <<locked>> | 86% | 47,137 psi | 73% | 2907 fps | 95.8% |
| Hodgdon H4831 SC | <<locked>> | 86% | 46,296 psi | 71% | 2890 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 43,207 psi | 66% | 2812 fps | 100% |
| Hodgdon Retumbo | 85.6 gr | 88% | 38,638 psi | 59% | 2858 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 49,995 psi | 77% | 2999 fps | 99.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,760 psi | 43% | 1814 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 45,701 psi | 70% | 2854 fps | 98.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 51,619 psi | 79% | 2959 fps | 99.4% |
| IMR 4831 | <<locked>> | 80% | 45,542 psi | 70% | 2867 fps | 99.9% |
| IMR 4955 Enduron | <<locked>> | 84% | 45,411 psi | 70% | 2844 fps | 95.5% |
| IMR 7828 SSC | <<locked>> | 86% | 42,395 psi | 65% | 2871 fps | 95.1% |
| Lovex S065 | <<locked>> | 80% | 49,284 psi | 76% | 2907 fps | 99.7% |
| Lovex S070 | <<locked>> | 80% | 47,616 psi | 73% | 2894 fps | 99.1% |
| Lovex S071 | <<locked>> | 82% | 33,083 psi | 51% | 2582 fps | 95.9% |
| Norma 204 | <<locked>> | 80% | 46,137 psi | 71% | 2894 fps | 97.3% |
| Norma 217 | <<locked>> | 94% | 34,809 psi | 54% | 2730 fps | 95.1% |
| Norma MRP | <<locked>> | 80% | 37,768 psi | 58% | 2785 fps | 96.5% |
| Norma URP | <<locked>> | 80% | 46,949 psi | 72% | 2913 fps | 99.9% |
| Ramshot Grand | <<locked>> | 86% | 42,308 psi | 65% | 2877 fps | 95.5% |
| Ramshot Hunter | <<locked>> | 80% | 46,035 psi | 71% | 2907 fps | 99.2% |
| Ramshot Magnum | <<locked>> | 86% | 38,130 psi | 59% | 2753 fps | 96.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,369 psi | 44% | 1857 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 48,356 psi | 74% | 2946 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 46,514 psi | 72% | 2963 fps | 99.9% |
| ReloadSwiss RS 76 | 89.5 gr | 86% | 35,563 psi | 55% | 2762 fps | 96% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 47,210 psi | 73% | 2992 fps | 95.8% |
| Rottweil R 903 | <<locked>> | 80% | 54,984 psi | 85% | 2995 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 44,135 psi | 68% | 2831 fps | 95.7% |
| Rottweil R 905 | <<locked>> | 80% | 39,421 psi | 61% | 2769 fps | 95.6% |
| Rottweil R 907 | <<locked>> | 80% | 50,270 psi | 77% | 2930 fps | 99% |
| Shooters World Long Rifle | <<locked>> | 80% | 49,284 psi | 76% | 2907 fps | 99.7% |
| Shooters World SW4350 | <<locked>> | 80% | 47,616 psi | 73% | 2894 fps | 99.1% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 54,389 psi | 84% | 2871 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 48,269 psi | 74% | 2848 fps | 99.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 39,088 psi | 60% | 2762 fps | 95.4% |
| Somchem S355 | <<locked>> | 80% | 54,650 psi | 84% | 2992 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 45,339 psi | 70% | 2812 fps | 95.3% |
| Somchem S365 | <<locked>> | 80% | 44,077 psi | 68% | 2864 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 40,030 psi | 62% | 2753 fps | 96.7% |
| Vihtavuori N150 | <<locked>> | 80% | 52,373 psi | 81% | 2910 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 48,501 psi | 75% | 2907 fps | 100% |
| Vihtavuori N165 | <<locked>> | 82% | 37,144 psi | 57% | 2674 fps | 95.4% |
| Vihtavuori N550 | <<locked>> | 80% | 47,848 psi | 74% | 2907 fps | 99.9% |
| Vihtavuori N555 | <<locked>> | 80% | 38,711 psi | 60% | 2766 fps | 99.4% |
| Vihtavuori N560 | <<locked>> | 84% | 43,903 psi | 68% | 2907 fps | 95% |
| Vihtavuori N565 | <<locked>> | 90% | 44,411 psi | 68% | 2890 fps | 95.6% |
| Vihtavuori N568 | <<locked>> | 96% | 48,269 psi | 74% | 3005 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 47,863 psi | 74% | 2858 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 49,937 psi | 77% | 2979 fps | 99.3% |
| Winchester StaBALL HD | 79.9 gr | 80% | 30,951 psi | 48% | 2697 fps | 99.6% |
| Winchester Supreme 780 | <<locked>> | 82% | 39,378 psi | 61% | 2730 fps | 95.5% |
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 75 powders for .300 Rem. Ultra Mag. loaded with the .308 | 150gr | Speer Boat-Tail. Hodgdon Retumbo delivers the highest muzzle velocity at 3,258 fps; across all powders the maximum-charge window runs from 2,018 fps to 3,258 fps. ADI AR 2217 gives the best case fill at 100 %, and 75 of the 75 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 150.0 gr projectile in 0.308" calls for a 1:15.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Bofors RP30 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, Winchester StaBALL HD, ReloadSwiss RS 76 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 150gr | Speer Boat-Tail 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.