Load Specifications
Load data in caliber .300 Rem. Ultra Mag. with .308 | 135gr | IBEX Viper bullet and 73 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% | 57,072 psi | 88% | 3140 fps | 99.9% |
| Accurate 4350 | <<locked>> | 86% | 57,827 psi | 89% | 3192 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 55,100 psi | 85% | 3215 fps | 96.3% |
| ADI AR 2208 | <<locked>> | 82% | 57,406 psi | 88% | 3146 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 57,899 psi | 89% | 3225 fps | 98.7% |
| ADI AR 2213 | <<locked>> | 94% | 55,854 psi | 86% | 3219 fps | 97.5% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 50,517 psi | 78% | 3097 fps | 96.6% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 45,716 psi | 70% | 3061 fps | 98.5% |
| Alliant Reloder-16 | <<locked>> | 88% | 57,450 psi | 88% | 3238 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 55,201 psi | 85% | 3199 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 92% | 57,421 psi | 88% | 3209 fps | 98.7% |
| Alliant Reloder-22 | <<locked>> | 94% | 56,188 psi | 86% | 3222 fps | 98.6% |
| Alliant Reloder-23 | <<locked>> | 96% | 57,174 psi | 88% | 3202 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 56,869 psi | 88% | 3255 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 92% | 58,262 psi | 90% | 3294 fps | 100% |
| Bofors RP15 | <<locked>> | 96% | 55,201 psi | 85% | 3202 fps | 98.4% |
| Bofors RP30ᴾ | <<locked>> | 100% | 53,200 psi | 82% | 3182 fps | 97.6% |
| Bofors RP5 | <<locked>> | 94% | 56,188 psi | 86% | 3222 fps | 98.6% |
| Bofors RP7 | <<locked>> | 84% | 55,854 psi | 86% | 3127 fps | 99% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 55,695 psi | 86% | 3196 fps | 98.4% |
| Hodgdon H414 | <<locked>> | 84% | 54,969 psi | 85% | 3173 fps | 99.3% |
| Hodgdon H4350 | <<locked>> | 84% | 57,276 psi | 88% | 3182 fps | 98.8% |
| Hodgdon H4831 | <<locked>> | 92% | 55,666 psi | 86% | 3153 fps | 96.7% |
| Hodgdon H4831 SC | <<locked>> | 94% | 58,421 psi | 90% | 3199 fps | 97.3% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 58,204 psi | 90% | 3156 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 55,651 psi | 86% | 3314 fps | 99.4% |
| Hodgdon Superformance | <<locked>> | 84% | 55,637 psi | 86% | 3199 fps | 99.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,115 psi | 57% | 2100 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 57,246 psi | 88% | 3156 fps | 99.2% |
| IMR 4451 Enduron | <<locked>> | 84% | 56,811 psi | 87% | 3146 fps | 99.4% |
| IMR 4831 | <<locked>> | 88% | 57,740 psi | 89% | 3176 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 56,724 psi | 87% | 3143 fps | 97.1% |
| IMR 7828 SSC | <<locked>> | 96% | 57,464 psi | 88% | 3255 fps | 97.8% |
| Lovex S065 | <<locked>> | 86% | 58,073 psi | 89% | 3153 fps | 99.9% |
| Lovex S070 | <<locked>> | 86% | 56,405 psi | 87% | 3143 fps | 99.5% |
| Lovex S071ᴾ | <<locked>> | 100% | 58,088 psi | 89% | 3153 fps | 99.9% |
| Norma 204 | <<locked>> | 88% | 58,639 psi | 90% | 3212 fps | 98.7% |
| Norma 217ᴾ | <<locked>> | 100% | 41,466 psi | 64% | 2989 fps | 96.6% |
| Norma MRP | <<locked>> | 92% | 56,086 psi | 86% | 3245 fps | 99.5% |
| Norma URP | <<locked>> | 86% | 55,622 psi | 86% | 3166 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 58,653 psi | 90% | 3278 fps | 98.4% |
| Ramshot Hunter | <<locked>> | 88% | 58,262 psi | 90% | 3219 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 98% | 57,392 psi | 88% | 3205 fps | 99.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,913 psi | 58% | 2146 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 58,436 psi | 90% | 3248 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 57,479 psi | 88% | 3202 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 55,521 psi | 85% | 3225 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 57,305 psi | 88% | 3317 fps | 100% |
| Rottweil R 903 | <<locked>> | 82% | 57,435 psi | 88% | 3143 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 55,347 psi | 85% | 3133 fps | 97.3% |
| Rottweil R 905 | <<locked>> | 92% | 57,174 psi | 88% | 3202 fps | 98.7% |
| Rottweil R 907 | <<locked>> | 84% | 55,854 psi | 86% | 3127 fps | 99% |
| Shooters World Long Rifle | <<locked>> | 86% | 58,073 psi | 89% | 3153 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 86% | 56,405 psi | 87% | 3143 fps | 99.5% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 58,523 psi | 90% | 3192 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 56,550 psi | 87% | 3009 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 57,406 psi | 88% | 3094 fps | 99.5% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 56,724 psi | 87% | 3199 fps | 98.7% |
| Somchem S355 | <<locked>> | 82% | 56,884 psi | 88% | 3133 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 57,537 psi | 89% | 3114 fps | 97.1% |
| Somchem S365 | <<locked>> | 88% | 56,072 psi | 86% | 3169 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 58,131 psi | 89% | 3176 fps | 99.3% |
| Vihtavuori N150 | <<locked>> | 84% | 58,088 psi | 89% | 3100 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 57,261 psi | 88% | 3156 fps | 100% |
| Vihtavuori N165 | <<locked>> | 96% | 57,435 psi | 88% | 3143 fps | 99.1% |
| Vihtavuori N550 | <<locked>> | 86% | 56,739 psi | 87% | 3159 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 56,217 psi | 87% | 3186 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 55,666 psi | 86% | 3228 fps | 97% |
| Vihtavuori N565 | <<locked>> | 98% | 56,449 psi | 87% | 3212 fps | 97.5% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 56,913 psi | 88% | 3100 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 55,172 psi | 85% | 3173 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 96% | 55,216 psi | 85% | 3284 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 57,812 psi | 89% | 3159 fps | 98.7% |
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% | 36,187 psi | 56% | 2746 fps | 95.9% |
| Accurate 4350 | <<locked>> | 80% | 47,369 psi | 73% | 3018 fps | 99.6% |
| Accurate MAGPRO | <<locked>> | 90% | 51,387 psi | 79% | 3150 fps | 95.3% |
| ADI AR 2208 | <<locked>> | 80% | 54,085 psi | 83% | 3097 fps | 100% |
| ADI AR 2209 | <<locked>> | 84% | 44,411 psi | 68% | 2979 fps | 95.7% |
| ADI AR 2213 | <<locked>> | 90% | 48,892 psi | 75% | 3091 fps | 95.7% |
| ADI AR 2217 | <<locked>> | 98% | 47,442 psi | 73% | 3038 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 94% | 37,811 psi | 58% | 2871 fps | 95.7% |
| Alliant Reloder-16 | <<locked>> | 80% | 44,280 psi | 68% | 3012 fps | 99.6% |
| Alliant Reloder-17 | <<locked>> | 80% | 51,445 psi | 79% | 3143 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 84% | 44,570 psi | 69% | 2976 fps | 95.9% |
| Alliant Reloder-22 | <<locked>> | 86% | 43,004 psi | 66% | 2976 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 34,127 psi | 53% | 2772 fps | 98.7% |
| Alliant Reloder-25 | <<locked>> | 84% | 33,968 psi | 52% | 2776 fps | 95.7% |
| Alliant Reloder-26 | <<locked>> | 80% | 37,536 psi | 58% | 2907 fps | 97.9% |
| Bofors RP15 | <<locked>> | 88% | 42,598 psi | 66% | 2963 fps | 95.2% |
| Bofors RP30 | <<locked>> | 96% | 46,441 psi | 71% | 3061 fps | 95.9% |
| Bofors RP5 | <<locked>> | 86% | 43,004 psi | 66% | 2976 fps | 95.5% |
| Bofors RP7 | <<locked>> | 80% | 49,400 psi | 76% | 3015 fps | 98% |
| Hodgdon H1000 | <<locked>> | 94% | 45,513 psi | 70% | 3002 fps | 95.7% |
| Hodgdon H414 | <<locked>> | 80% | 48,327 psi | 74% | 3054 fps | 98.3% |
| Hodgdon H4350 | <<locked>> | 80% | 50,459 psi | 78% | 3064 fps | 97.6% |
| Hodgdon H4831 | <<locked>> | 90% | 52,127 psi | 80% | 3094 fps | 95.9% |
| Hodgdon H4831 SC | <<locked>> | 90% | 51,198 psi | 79% | 3077 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 42,177 psi | 65% | 2894 fps | 99.8% |
| Hodgdon Retumbo | <<locked>> | 90% | 40,219 psi | 62% | 2982 fps | 95% |
| Hodgdon Superformance | <<locked>> | 80% | 48,051 psi | 74% | 3068 fps | 98.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,804 psi | 43% | 1890 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 44,701 psi | 69% | 2930 fps | 96.9% |
| IMR 4451 Enduron | <<locked>> | 80% | 50,343 psi | 77% | 3035 fps | 98.5% |
| IMR 4831 | <<locked>> | 80% | 44,744 psi | 69% | 2956 fps | 99.4% |
| IMR 4955 Enduron | <<locked>> | 88% | 50,125 psi | 77% | 3028 fps | 95.6% |
| IMR 7828 SSC | <<locked>> | 90% | 47,050 psi | 72% | 3064 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 48,486 psi | 75% | 2992 fps | 99.1% |
| Lovex S070 | <<locked>> | 80% | 46,905 psi | 72% | 2976 fps | 98.1% |
| Lovex S071 | <<locked>> | 84% | 35,563 psi | 55% | 2733 fps | 95.7% |
| Norma 204 | <<locked>> | 80% | 44,904 psi | 69% | 2966 fps | 95.7% |
| Norma 217 | <<locked>> | 98% | 38,986 psi | 60% | 2930 fps | 95.6% |
| Norma MRP | 80.8 gr | 82% | 39,697 psi | 61% | 2930 fps | 96% |
| Norma URP | <<locked>> | 80% | 45,861 psi | 71% | 2999 fps | 99.5% |
| Ramshot Grand | <<locked>> | 90% | 47,282 psi | 73% | 3074 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 44,831 psi | 69% | 2982 fps | 98.3% |
| Ramshot Magnum | <<locked>> | 88% | 40,030 psi | 62% | 2884 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,456 psi | 44% | 1936 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 54,375 psi | 84% | 3192 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 46,963 psi | 72% | 3028 fps | 99.5% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 44,875 psi | 69% | 3035 fps | 99.2% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 37,521 psi | 58% | 2897 fps | 95.3% |
| Rottweil R 903 | <<locked>> | 80% | 54,027 psi | 83% | 3091 fps | 100% |
| Rottweil R 904 | <<locked>> | 86% | 48,834 psi | 75% | 3015 fps | 95.8% |
| Rottweil R 905 | <<locked>> | 84% | 44,106 psi | 68% | 2966 fps | 95.9% |
| Rottweil R 907 | <<locked>> | 80% | 49,400 psi | 76% | 3015 fps | 98% |
| Shooters World Long Rifle | <<locked>> | 80% | 48,486 psi | 75% | 2992 fps | 99.1% |
| Shooters World SW4350 | <<locked>> | 80% | 46,905 psi | 72% | 2976 fps | 98.1% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 54,926 psi | 85% | 3136 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 53,200 psi | 82% | 2966 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 47,601 psi | 73% | 2933 fps | 98.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 84% | 43,714 psi | 67% | 2959 fps | 95.7% |
| Somchem S355 | <<locked>> | 80% | 53,577 psi | 82% | 3084 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 50,560 psi | 78% | 2999 fps | 95.5% |
| Somchem S365 | <<locked>> | 80% | 42,946 psi | 66% | 2956 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 39,508 psi | 61% | 2831 fps | 95.3% |
| Vihtavuori N150 | <<locked>> | 80% | 51,271 psi | 79% | 3002 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 47,224 psi | 73% | 2989 fps | 99.6% |
| Vihtavuori N165 | <<locked>> | 86% | 41,684 psi | 64% | 2864 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 46,804 psi | 72% | 2992 fps | 99.5% |
| Vihtavuori N555 | <<locked>> | 80% | 38,334 psi | 59% | 2858 fps | 98.6% |
| Vihtavuori N560 | 86.7 gr | 88% | 48,646 psi | 75% | 3100 fps | 95.2% |
| Vihtavuori N565 | <<locked>> | 94% | 49,313 psi | 76% | 3087 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 46,354 psi | 71% | 2940 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 48,501 psi | 75% | 3058 fps | 98.3% |
| Winchester StaBALL HD | 78 gr | 80% | 30,879 psi | 48% | 2779 fps | 98.8% |
| Winchester Supreme 780 | <<locked>> | 86% | 44,092 psi | 68% | 2923 fps | 95.8% |
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 73 powders for .300 Rem. Ultra Mag. loaded with the .308 | 135gr | IBEX Viper. ReloadSwiss RS 76 delivers the highest muzzle velocity at 3,317 fps; across all powders the maximum-charge window runs from 2,100 fps to 3,317 fps. ADI AR 2217 gives the best case fill at 100 %, and 73 of the 73 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 1:11.5 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. Winchester StaBALL HD, Norma MRP, Vihtavuori N560 rank at the top here: for .300 Rem. Ultra Mag. with the .308 | 135gr | IBEX Viper 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.