Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 138gr | Hasler ARIETE bullet and 79 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate MAGPRO, Alliant Reloder-26 and Ramshot Grand.
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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You can find more information in our FAQ: How can I use the Personalized Load Calculator?
Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 96% | 56,565 psi | 87% | 3123 fps | 99.9% |
| Accurate 4064 | <<locked>> | 82% | 58,755 psi | 90% | 3110 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 57,566 psi | 89% | 3176 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 55,492 psi | 85% | 3209 fps | 96.7% |
| ADI AR 2208 | <<locked>> | 84% | 58,508 psi | 90% | 3153 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 55,013 psi | 85% | 3166 fps | 98.5% |
| ADI AR 2213 | <<locked>> | 96% | 56,927 psi | 88% | 3225 fps | 97.9% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 42,235 psi | 65% | 2976 fps | 97.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 56,101 psi | 86% | 3120 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 58,436 psi | 90% | 3238 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 56,072 psi | 86% | 3196 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 58,392 psi | 90% | 3212 fps | 99% |
| Alliant Reloder-22 | <<locked>> | 96% | 56,724 psi | 87% | 3215 fps | 98.9% |
| Alliant Reloder-23 | <<locked>> | 98% | 57,769 psi | 89% | 3196 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 53,592 psi | 82% | 3189 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 92% | 54,549 psi | 84% | 3222 fps | 100% |
| Bofors RP15 | <<locked>> | 98% | 55,651 psi | 86% | 3196 fps | 98.7% |
| Bofors RP3 | <<locked>> | 82% | 57,174 psi | 88% | 3133 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 49,443 psi | 76% | 3104 fps | 97% |
| Bofors RP5 | <<locked>> | 96% | 56,724 psi | 87% | 3215 fps | 98.9% |
| Bofors RP7 | <<locked>> | 86% | 56,420 psi | 87% | 3127 fps | 99.2% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 52,591 psi | 81% | 3130 fps | 98% |
| Hodgdon H380 | <<locked>> | 82% | 57,479 psi | 88% | 3153 fps | 100% |
| Hodgdon H414 | <<locked>> | 86% | 55,680 psi | 86% | 3173 fps | 99.5% |
| Hodgdon H4350 | <<locked>> | 86% | 58,552 psi | 90% | 3192 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 94% | 56,913 psi | 88% | 3163 fps | 97.3% |
| Hodgdon H4831 SC | <<locked>> | 94% | 55,651 psi | 86% | 3143 fps | 97% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 58,798 psi | 90% | 3150 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 52,373 psi | 81% | 3241 fps | 99.1% |
| Hodgdon Superformance | <<locked>> | 86% | 56,840 psi | 87% | 3205 fps | 99.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,535 psi | 56% | 2080 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 57,856 psi | 89% | 3136 fps | 100% |
| IMR 4350 | <<locked>> | 90% | 58,204 psi | 90% | 3156 fps | 99.5% |
| IMR 4451 Enduron | <<locked>> | 86% | 58,015 psi | 89% | 3153 fps | 99.6% |
| IMR 4831 | <<locked>> | 90% | 57,914 psi | 89% | 3163 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 57,711 psi | 89% | 3146 fps | 97.6% |
| IMR 7828 SSC | <<locked>> | 98% | 58,552 psi | 90% | 3261 fps | 98.3% |
| Lovex S062 | <<locked>> | 82% | 58,001 psi | 89% | 3120 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 58,537 psi | 90% | 3150 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 56,637 psi | 87% | 3140 fps | 99.6% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,679 psi | 83% | 3077 fps | 99.7% |
| Norma 204 | <<locked>> | 88% | 55,709 psi | 86% | 3153 fps | 98.4% |
| Norma MRP | <<locked>> | 94% | 56,710 psi | 87% | 3241 fps | 99.7% |
| Norma URP | <<locked>> | 88% | 56,028 psi | 86% | 3159 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 55,361 psi | 85% | 3209 fps | 98.1% |
| Ramshot Hunter | <<locked>> | 88% | 55,085 psi | 85% | 3153 fps | 99.8% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 58,552 psi | 90% | 3209 fps | 99.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,202 psi | 57% | 2126 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 57,203 psi | 88% | 3136 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 55,390 psi | 85% | 3189 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 57,986 psi | 89% | 3196 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 56,449 psi | 87% | 3222 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 53,809 psi | 83% | 3241 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 84% | 57,421 psi | 88% | 3130 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 56,376 psi | 87% | 3136 fps | 97.8% |
| Rottweil R 905 | <<locked>> | 94% | 57,754 psi | 89% | 3199 fps | 99% |
| Rottweil R 907 | <<locked>> | 86% | 56,420 psi | 87% | 3127 fps | 99.2% |
| Shooters World Long Rifle | <<locked>> | 88% | 58,537 psi | 90% | 3150 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 58,001 psi | 89% | 3120 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 56,637 psi | 87% | 3140 fps | 99.6% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 55,550 psi | 85% | 3133 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 57,406 psi | 88% | 3009 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 58,146 psi | 89% | 3097 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 57,290 psi | 88% | 3192 fps | 98.9% |
| Somchem S355 | <<locked>> | 84% | 57,014 psi | 88% | 3127 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 58,421 psi | 90% | 3120 fps | 97.5% |
| Somchem S365 | <<locked>> | 90% | 56,347 psi | 87% | 3156 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 58,450 psi | 90% | 3169 fps | 99.5% |
| Vihtavuori N150 | <<locked>> | 86% | 58,755 psi | 90% | 3097 fps | 100% |
| Vihtavuori N160 | <<locked>> | 88% | 57,972 psi | 89% | 3153 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 58,146 psi | 89% | 3143 fps | 99.3% |
| Vihtavuori N550 | <<locked>> | 88% | 57,217 psi | 88% | 3153 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 55,767 psi | 86% | 3166 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 56,536 psi | 87% | 3232 fps | 97.5% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 56,405 psi | 87% | 3199 fps | 97.7% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 58,305 psi | 90% | 3104 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 55,869 psi | 86% | 3173 fps | 99.5% |
| Winchester StaBALL HD | <<locked>> | 98% | 55,840 psi | 86% | 3271 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 54,694 psi | 84% | 3100 fps | 98.5% |
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>> | 82% | 34,127 psi | 53% | 2690 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 54,926 psi | 85% | 3061 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 43,091 psi | 66% | 2930 fps | 99.2% |
| Accurate MAGPRO | 93.2 gr | 92% | 51,532 psi | 79% | 3136 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 80% | 51,416 psi | 79% | 3041 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 41,524 psi | 64% | 2910 fps | 95% |
| ADI AR 2213 | <<locked>> | 90% | 45,890 psi | 71% | 3018 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 96% | 36,796 psi | 57% | 2838 fps | 95.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 52,460 psi | 81% | 3064 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 41,466 psi | 64% | 2943 fps | 99.3% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,240 psi | 74% | 3074 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 41,568 psi | 64% | 2904 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 88% | 42,627 psi | 66% | 2956 fps | 95.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 30,516 psi | 47% | 2664 fps | 97.5% |
| Alliant Reloder-25 | <<locked>> | 86% | 32,779 psi | 50% | 2736 fps | 95.4% |
| Alliant Reloder-26 | 82 gr | 80% | 33,562 psi | 52% | 2792 fps | 96.6% |
| Bofors RP15 | <<locked>> | 90% | 42,206 psi | 65% | 2946 fps | 95.4% |
| Bofors RP3 | <<locked>> | 80% | 53,388 psi | 82% | 3077 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 42,714 psi | 66% | 2972 fps | 95% |
| Bofors RP5 | <<locked>> | 88% | 42,627 psi | 66% | 2956 fps | 95.7% |
| Bofors RP7 | <<locked>> | 80% | 46,137 psi | 71% | 2943 fps | 97.5% |
| Hodgdon H1000 | <<locked>> | 94% | 42,395 psi | 65% | 2927 fps | 95% |
| Hodgdon H380 | <<locked>> | 80% | 53,563 psi | 82% | 3094 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 45,020 psi | 69% | 2979 fps | 97.8% |
| Hodgdon H4350 | <<locked>> | 80% | 47,747 psi | 73% | 3005 fps | 97.2% |
| Hodgdon H4831 | <<locked>> | 90% | 49,269 psi | 76% | 3031 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 90% | 48,167 psi | 74% | 3012 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 38,914 psi | 60% | 2818 fps | 99.6% |
| Hodgdon Retumbo | <<locked>> | 92% | 39,537 psi | 61% | 2959 fps | 95.1% |
| Hodgdon Superformance | <<locked>> | 80% | 44,846 psi | 69% | 2992 fps | 97.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,253 psi | 42% | 1873 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 54,085 psi | 83% | 3077 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 41,756 psi | 64% | 2864 fps | 96.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 47,674 psi | 73% | 2976 fps | 98.2% |
| IMR 4831 | <<locked>> | 80% | 41,133 psi | 63% | 2874 fps | 99% |
| IMR 4955 Enduron | <<locked>> | 88% | 47,326 psi | 73% | 2966 fps | 95.1% |
| IMR 7828 SSC | <<locked>> | 92% | 47,239 psi | 73% | 3058 fps | 95.6% |
| Lovex S062 | <<locked>> | 80% | 54,476 psi | 84% | 3071 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 45,107 psi | 69% | 2920 fps | 98.8% |
| Lovex S070 | <<locked>> | 80% | 43,366 psi | 67% | 2900 fps | 97.5% |
| Lovex S071 | <<locked>> | 88% | 35,607 psi | 55% | 2726 fps | 95.9% |
| Norma 204 | <<locked>> | 82% | 44,947 psi | 69% | 2959 fps | 96% |
| Norma MRP | <<locked>> | 84% | 38,812 psi | 60% | 2897 fps | 95.8% |
| Norma URP | <<locked>> | 80% | 42,438 psi | 65% | 2920 fps | 99.1% |
| Ramshot Grand | 88.8 gr | 90% | 43,961 psi | 68% | 2995 fps | 95% |
| Ramshot Hunter | <<locked>> | 80% | 41,481 psi | 64% | 2904 fps | 97.7% |
| Ramshot Magnum | <<locked>> | 90% | 39,204 psi | 60% | 2858 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,775 psi | 43% | 1916 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 53,388 psi | 82% | 3074 fps | 99.5% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,314 psi | 79% | 3130 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 43,250 psi | 67% | 2946 fps | 99.1% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 41,713 psi | 64% | 2956 fps | 98.8% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 36,477 psi | 56% | 2861 fps | 95.2% |
| Rottweil R 903 | <<locked>> | 80% | 50,038 psi | 77% | 3018 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 45,977 psi | 71% | 2949 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 84% | 40,698 psi | 63% | 2884 fps | 95% |
| Rottweil R 907 | <<locked>> | 80% | 46,137 psi | 71% | 2943 fps | 97.5% |
| Shooters World Long Rifle | <<locked>> | 80% | 45,107 psi | 69% | 2920 fps | 98.8% |
| Shooters World Precision | <<locked>> | 80% | 54,476 psi | 84% | 3071 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 43,366 psi | 67% | 2900 fps | 97.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 51,764 psi | 80% | 3077 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 50,488 psi | 78% | 2913 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,179 psi | 68% | 2861 fps | 97.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 43,178 psi | 66% | 2940 fps | 95.8% |
| Somchem S355 | <<locked>> | 80% | 50,038 psi | 77% | 3018 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 50,763 psi | 78% | 2995 fps | 95.9% |
| Somchem S365 | <<locked>> | 80% | 39,204 psi | 60% | 2871 fps | 100% |
| Somchem S385 | <<locked>> | 82% | 38,450 psi | 59% | 2802 fps | 95.2% |
| Vihtavuori N150 | <<locked>> | 80% | 47,921 psi | 74% | 2940 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,034 psi | 68% | 2923 fps | 99.3% |
| Vihtavuori N165 | <<locked>> | 88% | 41,046 psi | 63% | 2841 fps | 95.8% |
| Vihtavuori N550 | <<locked>> | 80% | 43,439 psi | 67% | 2917 fps | 99.1% |
| Vihtavuori N555 | <<locked>> | 80% | 34,171 psi | 53% | 2749 fps | 97.5% |
| Vihtavuori N560 | <<locked>> | 90% | 48,776 psi | 75% | 3094 fps | 95.6% |
| Vihtavuori N565 | <<locked>> | 96% | 48,849 psi | 75% | 3068 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,555 psi | 67% | 2877 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 45,179 psi | 70% | 2982 fps | 97.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,021 psi | 42% | 2635 fps | 96.8% |
| Winchester Supreme 780 | <<locked>> | 86% | 40,770 psi | 63% | 2844 fps | 95% |
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 86 powders for .300 Rem. Ultra Mag. loaded with the .308 | 138gr | Hasler ARIETE. Winchester StaBALL HD delivers the highest muzzle velocity at 3,271 fps; across all powders the maximum-charge window runs from 2,080 fps to 3,271 fps. ADI AR 2217 gives the best case fill at 100 %, and 86 of the 86 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 138.0 gr projectile in 0.308" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Alliant Reloder-25 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. Accurate MAGPRO, Alliant Reloder-26, Ramshot Grand rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 138gr | Hasler ARIETE they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Baschieri & Pellagri 109, IMR 8133 Enduron, Vihtavuori N170 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.