Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 135gr | Sierra VarmintKing bullet and 75 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Winchester StaBALL HD, Norma MRP 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>> | 94% | 56,347 psi | 87% | 3136 fps | 99.9% |
| Accurate 4350 | <<locked>> | 86% | 56,840 psi | 87% | 3186 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 54,984 psi | 85% | 3219 fps | 96.6% |
| ADI AR 2208 | <<locked>> | 82% | 57,334 psi | 88% | 3156 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 58,088 psi | 89% | 3235 fps | 98.9% |
| ADI AR 2213 | <<locked>> | 94% | 56,086 psi | 86% | 3228 fps | 97.8% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 50,517 psi | 78% | 3107 fps | 97% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 45,237 psi | 70% | 3058 fps | 98.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 58,711 psi | 90% | 3179 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 57,580 psi | 89% | 3248 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 55,027 psi | 85% | 3202 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 92% | 57,595 psi | 89% | 3222 fps | 98.9% |
| Alliant Reloder-22 | <<locked>> | 94% | 56,217 psi | 87% | 3228 fps | 98.9% |
| Alliant Reloder-23 | <<locked>> | 96% | 57,435 psi | 88% | 3209 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 57,232 psi | 88% | 3261 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 92% | 58,494 psi | 90% | 3294 fps | 100% |
| Bofors RP15 | <<locked>> | 96% | 55,201 psi | 85% | 3209 fps | 98.6% |
| Bofors RP30ᴾ | <<locked>> | 100% | 53,113 psi | 82% | 3186 fps | 97.9% |
| Bofors RP5 | <<locked>> | 94% | 56,217 psi | 87% | 3228 fps | 98.9% |
| Bofors RP7 | <<locked>> | 84% | 55,288 psi | 85% | 3130 fps | 99.1% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 56,028 psi | 86% | 3209 fps | 98.7% |
| Hodgdon H414 | <<locked>> | 86% | 58,610 psi | 90% | 3238 fps | 99.7% |
| Hodgdon H4350 | <<locked>> | 84% | 57,203 psi | 88% | 3192 fps | 99% |
| Hodgdon H4831 | <<locked>> | 92% | 55,927 psi | 86% | 3166 fps | 97.1% |
| Hodgdon H4831 SC | <<locked>> | 94% | 58,726 psi | 90% | 3212 fps | 97.7% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 58,117 psi | 89% | 3163 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 55,869 psi | 86% | 3327 fps | 99.6% |
| Hodgdon Superformance | <<locked>> | 84% | 55,724 psi | 86% | 3205 fps | 99.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,796 psi | 57% | 2116 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 57,159 psi | 88% | 3166 fps | 99.4% |
| IMR 4451 Enduron | <<locked>> | 84% | 56,681 psi | 87% | 3156 fps | 99.5% |
| IMR 4831 | <<locked>> | 88% | 57,188 psi | 88% | 3173 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 56,753 psi | 87% | 3156 fps | 97.5% |
| IMR 7828 SSC | <<locked>> | 96% | 57,696 psi | 89% | 3268 fps | 98.2% |
| Lovex S065 | <<locked>> | 86% | 57,566 psi | 89% | 3156 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 55,767 psi | 86% | 3146 fps | 99.6% |
| Lovex S071ᴾ | <<locked>> | 100% | 57,392 psi | 88% | 3153 fps | 99.9% |
| Norma 204 | <<locked>> | 88% | 58,581 psi | 90% | 3219 fps | 98.9% |
| Norma 217ᴾ | <<locked>> | 100% | 40,785 psi | 63% | 2972 fps | 96.6% |
| Norma MRP | <<locked>> | 92% | 56,072 psi | 86% | 3248 fps | 99.6% |
| Norma URP | <<locked>> | 86% | 55,201 psi | 85% | 3166 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 54,665 psi | 84% | 3219 fps | 98% |
| Ramshot Hunter | <<locked>> | 88% | 58,030 psi | 89% | 3222 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 98% | 57,870 psi | 89% | 3215 fps | 99.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,637 psi | 58% | 2162 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 58,566 psi | 90% | 3248 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 57,217 psi | 88% | 3202 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 55,637 psi | 86% | 3232 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 57,798 psi | 89% | 3327 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 52,562 psi | 81% | 3189 fps | 96.4% |
| Rottweil R 903 | <<locked>> | 82% | 56,666 psi | 87% | 3143 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 55,245 psi | 85% | 3140 fps | 97.6% |
| Rottweil R 905 | <<locked>> | 92% | 57,072 psi | 88% | 3209 fps | 98.9% |
| Rottweil R 907 | <<locked>> | 84% | 55,288 psi | 85% | 3130 fps | 99.1% |
| Shooters World Long Rifle | <<locked>> | 86% | 57,566 psi | 89% | 3156 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 55,767 psi | 86% | 3146 fps | 99.6% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 58,349 psi | 90% | 3199 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 56,101 psi | 86% | 3015 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 56,927 psi | 88% | 3104 fps | 99.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 56,637 psi | 87% | 3205 fps | 98.9% |
| Somchem S355 | <<locked>> | 82% | 56,202 psi | 86% | 3136 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 57,377 psi | 88% | 3127 fps | 97.4% |
| Somchem S365 | <<locked>> | 88% | 55,782 psi | 86% | 3169 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 57,769 psi | 89% | 3179 fps | 99.5% |
| Vihtavuori N150 | <<locked>> | 84% | 57,580 psi | 89% | 3104 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 56,956 psi | 88% | 3159 fps | 100% |
| Vihtavuori N165 | <<locked>> | 96% | 57,348 psi | 88% | 3150 fps | 99.3% |
| Vihtavuori N550 | <<locked>> | 86% | 56,434 psi | 87% | 3163 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 55,680 psi | 86% | 3182 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 55,782 psi | 86% | 3235 fps | 97.3% |
| Vihtavuori N565 | <<locked>> | 98% | 56,260 psi | 87% | 3212 fps | 97.7% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 57,043 psi | 88% | 3107 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 58,798 psi | 90% | 3241 fps | 99.8% |
| Winchester StaBALL HD | <<locked>> | 96% | 55,651 psi | 86% | 3281 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 58,001 psi | 89% | 3169 fps | 99% |
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% | 34,360 psi | 53% | 2710 fps | 95.4% |
| Accurate 4350 | <<locked>> | 80% | 46,050 psi | 71% | 3005 fps | 99.6% |
| Accurate MAGPRO | <<locked>> | 90% | 51,111 psi | 79% | 3150 fps | 95.6% |
| ADI AR 2208 | <<locked>> | 80% | 53,650 psi | 83% | 3100 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 44,005 psi | 68% | 2979 fps | 95.9% |
| ADI AR 2213 | <<locked>> | 90% | 48,704 psi | 75% | 3097 fps | 96% |
| ADI AR 2217 | <<locked>> | 98% | 47,181 psi | 73% | 3045 fps | 96.1% |
| ADI AR 2225 | <<locked>> | 94% | 36,956 psi | 57% | 2858 fps | 95.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 55,143 psi | 85% | 3127 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 43,816 psi | 67% | 3012 fps | 99.6% |
| Alliant Reloder-17 | <<locked>> | 80% | 51,082 psi | 79% | 3140 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 43,918 psi | 68% | 2969 fps | 95.9% |
| Alliant Reloder-22 | <<locked>> | 86% | 42,322 psi | 65% | 2966 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 32,764 psi | 50% | 2743 fps | 98.4% |
| Alliant Reloder-25 | <<locked>> | 84% | 32,866 psi | 51% | 2753 fps | 95.4% |
| Alliant Reloder-26 | <<locked>> | 80% | 36,332 psi | 56% | 2877 fps | 97.7% |
| Bofors RP15 | <<locked>> | 88% | 42,061 psi | 65% | 2956 fps | 95.3% |
| Bofors RP30 | <<locked>> | 94% | 42,931 psi | 66% | 2989 fps | 95% |
| Bofors RP5 | <<locked>> | 86% | 42,322 psi | 65% | 2966 fps | 95.6% |
| Bofors RP7 | <<locked>> | 80% | 48,559 psi | 75% | 3012 fps | 98% |
| Hodgdon H1000 | <<locked>> | 94% | 45,150 psi | 69% | 3005 fps | 96.1% |
| Hodgdon H414 | <<locked>> | 80% | 47,645 psi | 73% | 3051 fps | 98.3% |
| Hodgdon H4350 | <<locked>> | 80% | 50,053 psi | 77% | 3071 fps | 97.8% |
| Hodgdon H4831 | <<locked>> | 88% | 48,443 psi | 75% | 3035 fps | 95.2% |
| Hodgdon H4831 SC | <<locked>> | 88% | 47,456 psi | 73% | 3018 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 41,379 psi | 64% | 2887 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 90% | 39,465 psi | 61% | 2972 fps | 95.1% |
| Hodgdon Superformance | <<locked>> | 80% | 47,790 psi | 74% | 3068 fps | 98.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,470 psi | 42% | 1903 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 43,976 psi | 68% | 2927 fps | 97% |
| IMR 4451 Enduron | <<locked>> | 80% | 49,893 psi | 77% | 3041 fps | 98.6% |
| IMR 4831 | <<locked>> | 80% | 43,627 psi | 67% | 2940 fps | 99.4% |
| IMR 4955 Enduron | <<locked>> | 88% | 49,734 psi | 77% | 3031 fps | 95.8% |
| IMR 7828 SSC | <<locked>> | 90% | 46,746 psi | 72% | 3068 fps | 95.6% |
| Lovex S065 | <<locked>> | 80% | 47,413 psi | 73% | 2986 fps | 99.1% |
| Lovex S070 | <<locked>> | 80% | 45,847 psi | 71% | 2969 fps | 98.1% |
| Lovex S071 | <<locked>> | 84% | 33,634 psi | 52% | 2694 fps | 95.1% |
| Norma 204 | <<locked>> | 80% | 44,324 psi | 68% | 2966 fps | 95.8% |
| Norma 217 | <<locked>> | 98% | 37,898 psi | 58% | 2904 fps | 95.4% |
| Norma MRP | 84.9 gr | 82% | 38,754 psi | 60% | 2910 fps | 95.8% |
| Norma URP | <<locked>> | 80% | 45,034 psi | 69% | 2989 fps | 99.5% |
| Ramshot Grand | <<locked>> | 90% | 46,934 psi | 72% | 3074 fps | 96% |
| Ramshot Hunter | <<locked>> | 80% | 44,121 psi | 68% | 2979 fps | 98.3% |
| Ramshot Magnum | <<locked>> | 88% | 39,059 psi | 60% | 2871 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,152 psi | 43% | 1952 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 54,317 psi | 84% | 3192 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 46,209 psi | 71% | 3022 fps | 99.5% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 44,353 psi | 68% | 3031 fps | 99.3% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 36,434 psi | 56% | 2874 fps | 95.2% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 48,559 psi | 75% | 3114 fps | 95.2% |
| Rottweil R 903 | <<locked>> | 80% | 52,924 psi | 81% | 3087 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 45,382 psi | 70% | 2959 fps | 95.1% |
| Rottweil R 905 | <<locked>> | 84% | 43,250 psi | 67% | 2956 fps | 95.9% |
| Rottweil R 907 | <<locked>> | 80% | 48,559 psi | 75% | 3012 fps | 98% |
| Shooters World Long Rifle | <<locked>> | 80% | 47,413 psi | 73% | 2986 fps | 99.1% |
| Shooters World SW4350 | <<locked>> | 80% | 45,847 psi | 71% | 2969 fps | 98.1% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 54,592 psi | 84% | 3140 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 52,620 psi | 81% | 2966 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 46,514 psi | 72% | 2927 fps | 98.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 42,888 psi | 66% | 2949 fps | 95.8% |
| Somchem S355 | <<locked>> | 80% | 52,576 psi | 81% | 3081 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 50,024 psi | 77% | 3002 fps | 95.8% |
| Somchem S365 | <<locked>> | 80% | 41,959 psi | 65% | 2940 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 38,276 psi | 59% | 2812 fps | 95.1% |
| Vihtavuori N150 | <<locked>> | 80% | 50,459 psi | 78% | 2999 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 46,543 psi | 72% | 2989 fps | 99.6% |
| Vihtavuori N165 | <<locked>> | 86% | 40,741 psi | 63% | 2851 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 46,050 psi | 71% | 2986 fps | 99.5% |
| Vihtavuori N555 | <<locked>> | 80% | 36,811 psi | 57% | 2828 fps | 98.4% |
| Vihtavuori N560 | 91.1 gr | 88% | 48,370 psi | 74% | 3100 fps | 95.5% |
| Vihtavuori N565 | <<locked>> | 94% | 48,776 psi | 75% | 3081 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 45,992 psi | 71% | 2940 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 47,819 psi | 74% | 3051 fps | 98.4% |
| Winchester StaBALL HD | 82 gr | 80% | 29,385 psi | 45% | 2733 fps | 98.3% |
| Winchester Supreme 780 | <<locked>> | 86% | 43,555 psi | 67% | 2917 fps | 95.9% |
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 81 powders for .300 Rem. Ultra Mag. loaded with the .308 | 135gr | Sierra VarmintKing. Hodgdon Retumbo delivers the highest muzzle velocity at 3,327 fps; across all powders the maximum-charge window runs from 2,116 fps to 3,327 fps. ADI AR 2217 gives the best case fill at 100 %, and 81 of the 81 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 135.0 gr projectile in 0.308" calls for a 1:17.0 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. Winchester StaBALL HD, Norma MRP, Vihtavuori N560 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 135gr | Sierra VarmintKing they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-33, 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.