Load Specifications
Load data in caliber .300 Weath. Mag. with .308 | 150gr | Barnes MRX BT bullet and 97 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 60, Winchester 760 and Alliant Reloder-16.
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 2495 | <<locked>> | 84% | 55,332 psi | 87% | 3022 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 57,638 psi | 90% | 3094 fps | 98.2% |
| Accurate 3100ᴾ | <<locked>> | 100% | 50,836 psi | 80% | 3054 fps | 98.6% |
| Accurate 4064 | <<locked>> | 86% | 55,869 psi | 88% | 3077 fps | 100% |
| Accurate 4350 | <<locked>> | 94% | 56,971 psi | 89% | 3182 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 82% | 55,172 psi | 86% | 3107 fps | 100% |
| ADI AR 2208 | <<locked>> | 88% | 56,623 psi | 89% | 3114 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 54,679 psi | 86% | 3166 fps | 97% |
| ADI Benchmark 8208 | <<locked>> | 82% | 57,464 psi | 90% | 3107 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 56,086 psi | 88% | 3245 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 98% | 54,607 psi | 86% | 3159 fps | 97% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 57,159 psi | 90% | 3136 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 86% | 57,609 psi | 90% | 3166 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 54,172 psi | 85% | 3189 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 90% | 55,506 psi | 87% | 3219 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 57,479 psi | 90% | 3209 fps | 97.6% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 50,908 psi | 80% | 3140 fps | 96.4% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 47,979 psi | 75% | 3081 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 41,800 psi | 66% | 2976 fps | 97.4% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 55,535 psi | 87% | 3291 fps | 99.9% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 55,492 psi | 87% | 3127 fps | 99.9% |
| Bofors RP3 | <<locked>> | 86% | 54,317 psi | 85% | 3097 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 50,908 psi | 80% | 3140 fps | 96.4% |
| Bofors RP7 | <<locked>> | 92% | 57,537 psi | 90% | 3133 fps | 98.4% |
| Hodgdon BL-C2 | <<locked>> | 82% | 57,551 psi | 90% | 3136 fps | 100% |
| Hodgdon H380 | <<locked>> | 86% | 55,027 psi | 86% | 3114 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 92% | 55,666 psi | 87% | 3179 fps | 98.6% |
| Hodgdon H4350 | <<locked>> | 90% | 55,680 psi | 87% | 3140 fps | 97.5% |
| Hodgdon H4895 | <<locked>> | 82% | 55,796 psi | 87% | 3120 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 54,433 psi | 85% | 3110 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 56,362 psi | 88% | 3159 fps | 100% |
| Hodgdon Superformance | <<locked>> | 92% | 56,202 psi | 88% | 3219 fps | 98.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,955 psi | 56% | 1962 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 57,058 psi | 89% | 3120 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 56,420 psi | 88% | 3097 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 55,956 psi | 88% | 3097 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 55,288 psi | 87% | 3074 fps | 98.5% |
| IMR 4350 | <<locked>> | 94% | 55,071 psi | 86% | 3107 fps | 98.1% |
| IMR 4451 Enduron | <<locked>> | 90% | 55,840 psi | 88% | 3107 fps | 98.5% |
| IMR 4831 | <<locked>> | 96% | 57,435 psi | 90% | 3173 fps | 100% |
| IMR 4895 | <<locked>> | 84% | 55,463 psi | 87% | 3136 fps | 100% |
| IMR 8208 XBR | <<locked>> | 82% | 57,464 psi | 90% | 3107 fps | 100% |
| Lovex D073.6 | <<locked>> | 82% | 55,419 psi | 87% | 3077 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 57,696 psi | 90% | 3087 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 56,043 psi | 88% | 3091 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 55,695 psi | 87% | 3100 fps | 99.4% |
| Lovex S070 | <<locked>> | 94% | 57,043 psi | 89% | 3146 fps | 98.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 42,076 psi | 66% | 2884 fps | 96.7% |
| Norma 201 | <<locked>> | 84% | 57,392 psi | 90% | 3104 fps | 100% |
| Norma 202 | <<locked>> | 82% | 54,708 psi | 86% | 3048 fps | 100% |
| Norma 203B | <<locked>> | 86% | 56,869 psi | 89% | 3146 fps | 100% |
| Norma 204 | <<locked>> | 94% | 55,999 psi | 88% | 3163 fps | 97.1% |
| Norma MRPᴾ | <<locked>> | 100% | 54,143 psi | 85% | 3232 fps | 98.4% |
| Norma URP | <<locked>> | 94% | 55,796 psi | 87% | 3169 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 84% | 54,128 psi | 85% | 3117 fps | 100% |
| Ramshot Hunter | <<locked>> | 94% | 54,723 psi | 86% | 3166 fps | 99.1% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,666 psi | 57% | 2011 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 54,955 psi | 86% | 3094 fps | 98.9% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 54,853 psi | 86% | 3176 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 54,969 psi | 86% | 3212 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 57,000 psi | 89% | 3209 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 55,709 psi | 87% | 3238 fps | 99.8% |
| Rottweil R 902 | <<locked>> | 84% | 54,447 psi | 85% | 3048 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 54,375 psi | 85% | 3091 fps | 100% |
| Rottweil R 904 | <<locked>> | 98% | 56,405 psi | 88% | 3136 fps | 96.2% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 56,608 psi | 89% | 3192 fps | 97.6% |
| Rottweil R 907 | <<locked>> | 92% | 57,537 psi | 90% | 3133 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 92% | 55,695 psi | 87% | 3100 fps | 99.4% |
| Shooters World Match Rifle | <<locked>> | 82% | 55,419 psi | 87% | 3077 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 56,043 psi | 88% | 3091 fps | 100% |
| Shooters World SW4350 | <<locked>> | 94% | 57,043 psi | 89% | 3146 fps | 98.9% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 56,347 psi | 88% | 3159 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 56,463 psi | 88% | 3110 fps | 99.7% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 57,551 psi | 90% | 3136 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 54,984 psi | 86% | 2986 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 55,782 psi | 87% | 2982 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 55,680 psi | 87% | 3054 fps | 98.6% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 56,115 psi | 88% | 3189 fps | 97.5% |
| Somchem S335 | <<locked>> | 82% | 54,491 psi | 85% | 2979 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 56,434 psi | 88% | 3100 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 54,389 psi | 85% | 3087 fps | 100% |
| Somchem S365 | <<locked>> | 96% | 54,853 psi | 86% | 3169 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 57,305 psi | 90% | 3169 fps | 98.4% |
| Vihtavuori N133 | <<locked>> | 82% | 55,506 psi | 87% | 2969 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 54,853 psi | 86% | 3012 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 55,288 psi | 87% | 3025 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 55,985 psi | 88% | 3064 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 54,375 psi | 85% | 3107 fps | 99.8% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 49,371 psi | 77% | 3015 fps | 96.5% |
| Vihtavuori N540 | <<locked>> | 86% | 57,188 psi | 90% | 3074 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 56,985 psi | 89% | 3166 fps | 99.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 53,708 psi | 84% | 3166 fps | 100% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 54,172 psi | 85% | 3074 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 55,883 psi | 88% | 3182 fps | 98.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 43,250 psi | 68% | 3120 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 84% | 57,653 psi | 90% | 3140 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 54,012 psi | 85% | 3104 fps | 96.9% |
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 2495 | <<locked>> | 80% | 48,327 psi | 76% | 2913 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 46,963 psi | 74% | 2904 fps | 96.1% |
| Accurate 3100 | <<locked>> | 92% | 38,348 psi | 60% | 2802 fps | 95.5% |
| Accurate 4064 | <<locked>> | 80% | 45,803 psi | 72% | 2913 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 34,505 psi | 54% | 2733 fps | 95.9% |
| ADI AR 2206H | <<locked>> | 80% | 51,750 psi | 81% | 3048 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 43,918 psi | 69% | 2884 fps | 99% |
| ADI AR 2209 | <<locked>> | 94% | 47,834 psi | 75% | 3035 fps | 95.3% |
| ADI Benchmark 8208 | <<locked>> | 80% | 53,911 psi | 84% | 3051 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 48,356 psi | 76% | 3107 fps | 99.6% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 47,819 psi | 75% | 3031 fps | 95.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 44,222 psi | 69% | 2913 fps | 99.8% |
| Alliant Reloder-15 | <<locked>> | 80% | 47,253 psi | 74% | 2982 fps | 99.5% |
| Alliant Reloder-16 | 62.7 gr | 80% | 34,171 psi | 54% | 2749 fps | 96.1% |
| Alliant Reloder-17 | <<locked>> | 80% | 38,783 psi | 61% | 2894 fps | 99% |
| Alliant Reloder-19 | <<locked>> | 94% | 47,166 psi | 74% | 3022 fps | 95.3% |
| Alliant Reloder-22 | <<locked>> | 98% | 47,587 psi | 75% | 3074 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 86% | 30,168 psi | 47% | 2651 fps | 96% |
| Alliant Reloder-25 | <<locked>> | 96% | 36,651 psi | 57% | 2844 fps | 95.4% |
| Alliant Reloder-26 | <<locked>> | 88% | 35,201 psi | 55% | 2851 fps | 95.7% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 51,692 psi | 81% | 3061 fps | 99.7% |
| Bofors RP3 | <<locked>> | 80% | 44,179 psi | 69% | 2917 fps | 99.8% |
| Bofors RP5 | <<locked>> | 98% | 47,587 psi | 75% | 3074 fps | 95.5% |
| Bofors RP7 | <<locked>> | 84% | 44,556 psi | 70% | 2890 fps | 95.7% |
| Hodgdon BL-C2 | <<locked>> | 80% | 53,737 psi | 84% | 3077 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 44,759 psi | 70% | 2923 fps | 98.3% |
| Hodgdon H414 | <<locked>> | 84% | 42,366 psi | 66% | 2923 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 84% | 45,716 psi | 72% | 2949 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 52,315 psi | 82% | 3061 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 31,589 psi | 50% | 2638 fps | 96.8% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 49,037 psi | 77% | 3035 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 41,698 psi | 65% | 2933 fps | 95% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,803 psi | 42% | 1759 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 50,154 psi | 79% | 3005 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 52,953 psi | 83% | 3048 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 46,166 psi | 72% | 2923 fps | 99.4% |
| IMR 4166 Enduron | <<locked>> | 80% | 48,689 psi | 76% | 2956 fps | 97.3% |
| IMR 4350 | <<locked>> | 86% | 42,583 psi | 67% | 2867 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 80% | 40,770 psi | 64% | 2812 fps | 95% |
| IMR 4831 | <<locked>> | 80% | 33,431 psi | 52% | 2687 fps | 95.6% |
| IMR 4895 | <<locked>> | 80% | 48,457 psi | 76% | 3015 fps | 99.8% |
| IMR 8208 XBR | <<locked>> | 80% | 53,911 psi | 84% | 3051 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 51,880 psi | 81% | 3025 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 51,024 psi | 80% | 2976 fps | 99.9% |
| Lovex S062 | <<locked>> | 80% | 46,325 psi | 73% | 2923 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 37,985 psi | 60% | 2749 fps | 95.7% |
| Lovex S070 | <<locked>> | 84% | 41,278 psi | 65% | 2841 fps | 95.6% |
| Lovex S071 | <<locked>> | 98% | 39,218 psi | 61% | 2822 fps | 95.8% |
| Norma 201 | <<locked>> | 80% | 50,444 psi | 79% | 2989 fps | 100% |
| Norma 202 | <<locked>> | 80% | 51,256 psi | 80% | 2995 fps | 100% |
| Norma 203B | <<locked>> | 80% | 46,601 psi | 73% | 2969 fps | 99.7% |
| Norma 204 | <<locked>> | 90% | 48,573 psi | 76% | 3028 fps | 95.4% |
| Norma MRP | <<locked>> | 94% | 43,714 psi | 69% | 3025 fps | 96% |
| Norma URP | <<locked>> | 80% | 34,693 psi | 54% | 2736 fps | 95.9% |
| Ramshot Big Game | <<locked>> | 80% | 46,920 psi | 74% | 2989 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 84% | 38,827 psi | 61% | 2848 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,180 psi | 43% | 1798 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 44,991 psi | 71% | 2907 fps | 97% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 51,010 psi | 80% | 3110 fps | 99.8% |
| ReloadSwiss RS 60 | 67.6 gr | 80% | 41,321 psi | 65% | 2963 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 34,461 psi | 54% | 2749 fps | 95.5% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 36,289 psi | 57% | 2822 fps | 95.6% |
| Rottweil R 902 | <<locked>> | 80% | 48,008 psi | 75% | 2940 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 41,495 psi | 65% | 2854 fps | 99.4% |
| Rottweil R 904 | <<locked>> | 96% | 52,794 psi | 83% | 3074 fps | 95.4% |
| Rottweil R 905 | <<locked>> | 94% | 46,093 psi | 72% | 3002 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 84% | 44,556 psi | 70% | 2890 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 37,985 psi | 60% | 2749 fps | 95.7% |
| Shooters World Match Rifle | <<locked>> | 80% | 51,880 psi | 81% | 3025 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 46,325 psi | 73% | 2923 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 41,278 psi | 65% | 2841 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 42,859 psi | 67% | 2913 fps | 99.2% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 52,721 psi | 83% | 3048 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 50,314 psi | 79% | 3015 fps | 99.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 51,430 psi | 81% | 2930 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 43,294 psi | 68% | 2782 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 39,856 psi | 62% | 2749 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 45,672 psi | 72% | 2995 fps | 95% |
| Somchem S335 | <<locked>> | 80% | 51,155 psi | 80% | 2927 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 52,533 psi | 82% | 3038 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 42,003 psi | 66% | 2858 fps | 99.4% |
| Somchem S365 | <<locked>> | 80% | 31,183 psi | 49% | 2684 fps | 98% |
| Somchem S385 | <<locked>> | 92% | 43,743 psi | 69% | 2920 fps | 95.4% |
| Vihtavuori N133 | <<locked>> | 80% | 51,996 psi | 81% | 2917 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 48,095 psi | 75% | 2907 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 48,544 psi | 76% | 2920 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 40,132 psi | 63% | 2785 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 80% | 36,114 psi | 57% | 2743 fps | 96.4% |
| Vihtavuori N165 | <<locked>> | 98% | 46,122 psi | 72% | 2953 fps | 95.7% |
| Vihtavuori N540 | <<locked>> | 80% | 46,862 psi | 73% | 2910 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 35,592 psi | 56% | 2736 fps | 95.9% |
| Vihtavuori N555 | <<locked>> | 84% | 30,908 psi | 48% | 2671 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 35,520 psi | 56% | 2710 fps | 98.4% |
| Winchester 760 | 69.5 gr | 84% | 42,525 psi | 67% | 2923 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 88% | 28,485 psi | 45% | 2677 fps | 95.7% |
| Winchester StaBALL Match | <<locked>> | 80% | 50,270 psi | 79% | 3022 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 46,746 psi | 73% | 2972 fps | 95.1% |
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 97 powders for .300 Weath. Mag. loaded with the .308 | 150gr | Barnes MRX BT. Alliant Reloder-26 delivers the highest muzzle velocity at 3,291 fps; across all powders the maximum-charge window runs from 1,962 fps to 3,291 fps. Accurate 3100 gives the best case fill at 100 %, and 97 of the 97 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 150.0 gr projectile in 0.308" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-19, Alliant Reloder-22 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. ReloadSwiss RS 60, Winchester 760, Alliant Reloder-16 rank at the top here: for .300 Weath. Mag. with the .308 | 150gr | Barnes MRX BT 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.