Load Specifications
Load data in caliber .308 Norma Mag. with .308 | 155gr | Merlin Virtus 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 70, Hodgdon Superformance and ReloadSwiss RS 60.
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 2015 | <<locked>> | 82% | 54,375 psi | 85% | 2890 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 56,942 psi | 89% | 2963 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 55,216 psi | 87% | 2986 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 56,144 psi | 88% | 2976 fps | 97.4% |
| Accurate 3100ᴾ | <<locked>> | 100% | 44,541 psi | 70% | 2864 fps | 96.8% |
| Accurate 4064 | <<locked>> | 90% | 57,101 psi | 89% | 3015 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 54,012 psi | 85% | 3058 fps | 99.6% |
| ADI AR 2206H | <<locked>> | 86% | 57,537 psi | 90% | 3058 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 55,027 psi | 86% | 3002 fps | 99.8% |
| ADI Benchmark 8208 | <<locked>> | 84% | 56,231 psi | 88% | 3002 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 57,696 psi | 90% | 2976 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 53,983 psi | 85% | 3123 fps | 99.9% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 54,563 psi | 86% | 3012 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 55,376 psi | 87% | 3025 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 55,767 psi | 87% | 3048 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 98% | 55,274 psi | 87% | 3120 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 94% | 56,840 psi | 89% | 3156 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 42,177 psi | 66% | 2894 fps | 99.3% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 47,805 psi | 75% | 3074 fps | 98.9% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 57,522 psi | 90% | 3071 fps | 99.9% |
| Bofors RP3 | <<locked>> | 90% | 55,898 psi | 88% | 3038 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 55,782 psi | 87% | 3012 fps | 97.6% |
| Hodgdon Benchmark | <<locked>> | 82% | 54,317 psi | 85% | 2930 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 55,869 psi | 88% | 3028 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 56,811 psi | 89% | 3054 fps | 99.6% |
| Hodgdon H414 | <<locked>> | 96% | 57,029 psi | 89% | 3114 fps | 98.4% |
| Hodgdon H4350 | <<locked>> | 94% | 57,334 psi | 90% | 3074 fps | 97.3% |
| Hodgdon H4895 | <<locked>> | 84% | 54,404 psi | 85% | 3009 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 55,158 psi | 86% | 3041 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 54,331 psi | 85% | 3045 fps | 100% |
| Hodgdon Superformance | <<locked>> | 94% | 53,766 psi | 84% | 3087 fps | 97.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,650 psi | 56% | 1873 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 55,869 psi | 88% | 3015 fps | 100% |
| IMR 3031 | <<locked>> | 84% | 54,665 psi | 86% | 2992 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 54,447 psi | 85% | 2986 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 86% | 54,346 psi | 85% | 2963 fps | 97.8% |
| IMR 4350 | <<locked>> | 98% | 56,391 psi | 88% | 3038 fps | 97.7% |
| IMR 4451 Enduron | <<locked>> | 92% | 54,476 psi | 85% | 2992 fps | 97.8% |
| IMR 4831 | <<locked>> | 98% | 54,708 psi | 86% | 3051 fps | 99.7% |
| IMR 4895 | <<locked>> | 88% | 57,232 psi | 90% | 3077 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 56,231 psi | 88% | 3002 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 57,421 psi | 90% | 3025 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 56,695 psi | 89% | 2979 fps | 100% |
| Lovex S062 | <<locked>> | 88% | 54,404 psi | 85% | 2979 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 57,203 psi | 90% | 3035 fps | 99.2% |
| Lovex S070 | <<locked>> | 96% | 54,955 psi | 86% | 3022 fps | 98.2% |
| Norma 201 | <<locked>> | 86% | 55,869 psi | 88% | 2992 fps | 100% |
| Norma 202 | <<locked>> | 86% | 56,826 psi | 89% | 2999 fps | 100% |
| Norma 203B | <<locked>> | 88% | 55,013 psi | 86% | 3035 fps | 100% |
| Norma 204 | <<locked>> | 98% | 57,435 psi | 90% | 3094 fps | 96.7% |
| Norma MRPᴾ | <<locked>> | 100% | 47,587 psi | 75% | 3028 fps | 96.4% |
| Norma URP | <<locked>> | 98% | 56,855 psi | 89% | 3104 fps | 99.8% |
| Ramshot Big Game | <<locked>> | 88% | 55,883 psi | 88% | 3061 fps | 100% |
| Ramshot Hunter | <<locked>> | 98% | 55,637 psi | 87% | 3097 fps | 98.8% |
| Ramshot TAC | <<locked>> | 84% | 56,579 psi | 89% | 3022 fps | 99.2% |
| Ramshot Wild Boar | <<locked>> | 84% | 56,376 psi | 88% | 3038 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 56,985 psi | 89% | 2999 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,998 psi | 56% | 1913 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 57,101 psi | 89% | 3038 fps | 98.7% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 56,695 psi | 89% | 3123 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 56,507 psi | 89% | 3156 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 54,027 psi | 85% | 3081 fps | 99.5% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 57,174 psi | 90% | 3173 fps | 99.7% |
| Rottweil R 901 | <<locked>> | 84% | 56,507 psi | 89% | 2969 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 56,405 psi | 88% | 2992 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 55,767 psi | 87% | 3031 fps | 100% |
| Rottweil R 907 | <<locked>> | 94% | 55,782 psi | 87% | 3012 fps | 97.6% |
| Shooters World Long Rifle | <<locked>> | 96% | 57,203 psi | 90% | 3035 fps | 99.2% |
| Shooters World Match Rifle | <<locked>> | 86% | 57,421 psi | 90% | 3025 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 54,404 psi | 85% | 2979 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 54,955 psi | 86% | 3022 fps | 98.2% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 54,157 psi | 85% | 3041 fps | 99.9% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 55,114 psi | 86% | 2999 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 56,028 psi | 88% | 3025 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 57,334 psi | 90% | 2930 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 54,418 psi | 85% | 2881 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 57,493 psi | 90% | 2989 fps | 98.3% |
| Somchem S335 | <<locked>> | 86% | 56,710 psi | 89% | 2927 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 54,853 psi | 86% | 2989 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 55,985 psi | 88% | 3028 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 55,259 psi | 87% | 3104 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 50,749 psi | 80% | 2972 fps | 96.6% |
| Vihtavuori N130 | <<locked>> | 82% | 56,869 psi | 89% | 2887 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 57,696 psi | 90% | 2913 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 56,608 psi | 89% | 2956 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 57,348 psi | 90% | 2972 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 57,580 psi | 90% | 3005 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 55,593 psi | 87% | 3041 fps | 99.7% |
| Vihtavuori N530 | <<locked>> | 84% | 56,855 psi | 89% | 3002 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 55,622 psi | 87% | 2969 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 54,621 psi | 86% | 3045 fps | 99.5% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 46,905 psi | 74% | 2976 fps | 99.2% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 55,796 psi | 87% | 3015 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 57,101 psi | 89% | 3051 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 57,305 psi | 90% | 3120 fps | 98.4% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 37,826 psi | 59% | 2904 fps | 99.4% |
| Winchester StaBALL Match | <<locked>> | 86% | 56,014 psi | 88% | 3031 fps | 100% |
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 2015 | <<locked>> | 80% | 51,184 psi | 80% | 2844 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 43,526 psi | 68% | 2759 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 51,517 psi | 81% | 2930 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 45,861 psi | 72% | 2795 fps | 95.1% |
| Accurate 3100 | <<locked>> | 96% | 38,537 psi | 60% | 2740 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 41,205 psi | 65% | 2756 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 35,157 psi | 55% | 2684 fps | 95.7% |
| ADI AR 2206H | <<locked>> | 80% | 47,413 psi | 74% | 2887 fps | 99.5% |
| ADI AR 2208 | <<locked>> | 80% | 40,234 psi | 63% | 2726 fps | 97.9% |
| ADI Benchmark 8208 | <<locked>> | 80% | 49,574 psi | 78% | 2894 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 50,343 psi | 79% | 2871 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 43,511 psi | 68% | 2923 fps | 98.6% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 48,066 psi | 75% | 2900 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 39,943 psi | 63% | 2746 fps | 99% |
| Alliant Reloder-15 | <<locked>> | 80% | 43,018 psi | 67% | 2818 fps | 98.6% |
| Alliant Reloder-16 | <<locked>> | 84% | 35,302 psi | 55% | 2703 fps | 95.9% |
| Alliant Reloder-17 | <<locked>> | 80% | 34,722 psi | 54% | 2713 fps | 97.5% |
| Alliant Reloder-23 | <<locked>> | 90% | 30,545 psi | 48% | 2595 fps | 95.6% |
| Alliant Reloder-26 | <<locked>> | 92% | 35,679 psi | 56% | 2792 fps | 95.2% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 46,862 psi | 73% | 2890 fps | 98.8% |
| Bofors RP3 | <<locked>> | 80% | 39,769 psi | 62% | 2749 fps | 99.1% |
| Bofors RP7 | <<locked>> | 88% | 46,079 psi | 72% | 2838 fps | 95.5% |
| Hodgdon Benchmark | <<locked>> | 80% | 51,097 psi | 80% | 2881 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 48,762 psi | 76% | 2917 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 40,524 psi | 64% | 2756 fps | 96.9% |
| Hodgdon H414 | <<locked>> | 88% | 43,366 psi | 68% | 2864 fps | 95.4% |
| Hodgdon H4350 | <<locked>> | 90% | 50,314 psi | 79% | 2953 fps | 95.8% |
| Hodgdon H4895 | <<locked>> | 80% | 47,921 psi | 75% | 2897 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 30,313 psi | 48% | 2533 fps | 95.7% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 44,077 psi | 69% | 2864 fps | 99.6% |
| Hodgdon Superformance | 71.3 gr | 90% | 46,340 psi | 73% | 2949 fps | 95.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,542 psi | 42% | 1677 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 45,948 psi | 72% | 2844 fps | 99.6% |
| IMR 3031 | <<locked>> | 80% | 47,761 psi | 75% | 2887 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 42,264 psi | 66% | 2762 fps | 98.5% |
| IMR 4166 Enduron | <<locked>> | 80% | 44,672 psi | 70% | 2785 fps | 95.7% |
| IMR 4350 | <<locked>> | 92% | 46,688 psi | 73% | 2867 fps | 95.7% |
| IMR 4451 Enduron | <<locked>> | 86% | 45,020 psi | 71% | 2818 fps | 95.7% |
| IMR 4831 | <<locked>> | 84% | 34,084 psi | 53% | 2638 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 44,106 psi | 69% | 2851 fps | 99.2% |
| IMR 8208 XBR | <<locked>> | 80% | 49,574 psi | 78% | 2894 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 46,775 psi | 73% | 2861 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 47,036 psi | 74% | 2818 fps | 99.5% |
| Lovex S062 | <<locked>> | 80% | 42,090 psi | 66% | 2762 fps | 99.6% |
| Lovex S065 | <<locked>> | 84% | 39,189 psi | 61% | 2700 fps | 95.6% |
| Lovex S070 | <<locked>> | 88% | 42,424 psi | 66% | 2789 fps | 95.3% |
| Norma 201 | <<locked>> | 80% | 46,151 psi | 72% | 2831 fps | 99.9% |
| Norma 202 | <<locked>> | 80% | 46,659 psi | 73% | 2838 fps | 100% |
| Norma 203B | <<locked>> | 80% | 42,351 psi | 66% | 2805 fps | 98.9% |
| Norma 204 | <<locked>> | 94% | 50,111 psi | 79% | 2972 fps | 95.1% |
| Norma MRP | <<locked>> | 98% | 44,309 psi | 69% | 2959 fps | 95.5% |
| Norma URP | <<locked>> | 84% | 35,549 psi | 56% | 2687 fps | 95.7% |
| Ramshot Big Game | <<locked>> | 80% | 42,250 psi | 66% | 2822 fps | 98.7% |
| Ramshot Hunter | <<locked>> | 88% | 39,581 psi | 62% | 2789 fps | 95.2% |
| Ramshot TAC | <<locked>> | 80% | 49,414 psi | 77% | 2900 fps | 98.3% |
| Ramshot Wild Boar | <<locked>> | 80% | 49,298 psi | 77% | 2923 fps | 99.7% |
| Ramshot X-Terminator | <<locked>> | 80% | 53,374 psi | 84% | 2946 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,760 psi | 42% | 1713 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 40,944 psi | 64% | 2740 fps | 95.3% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 45,716 psi | 72% | 2930 fps | 99% |
| ReloadSwiss RS 60 | 60 gr | 80% | 36,985 psi | 58% | 2785 fps | 99.8% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 35,070 psi | 55% | 2703 fps | 95.3% |
| ReloadSwiss RS 70 | 65.5 gr | 86% | 37,550 psi | 59% | 2776 fps | 95.5% |
| Rottweil R 901 | <<locked>> | 80% | 50,067 psi | 78% | 2871 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 43,903 psi | 69% | 2779 fps | 99.7% |
| Rottweil R 903 | <<locked>> | 80% | 37,246 psi | 58% | 2687 fps | 98.3% |
| Rottweil R 907 | <<locked>> | 88% | 46,079 psi | 72% | 2838 fps | 95.5% |
| Shooters World Long Rifle | <<locked>> | 84% | 39,189 psi | 61% | 2700 fps | 95.6% |
| Shooters World Match Rifle | <<locked>> | 80% | 46,775 psi | 73% | 2861 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 42,090 psi | 66% | 2762 fps | 99.6% |
| Shooters World SW4350 | <<locked>> | 88% | 42,424 psi | 66% | 2789 fps | 95.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 38,493 psi | 60% | 2743 fps | 98% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 47,819 psi | 75% | 2874 fps | 98.4% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 45,847 psi | 72% | 2851 fps | 99.3% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 47,601 psi | 75% | 2782 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 39,755 psi | 62% | 2638 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 44,106 psi | 69% | 2756 fps | 95.6% |
| Somchem S335 | <<locked>> | 80% | 47,065 psi | 74% | 2779 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 47,688 psi | 75% | 2871 fps | 99.5% |
| Somchem S355 | <<locked>> | 80% | 38,014 psi | 60% | 2697 fps | 98.3% |
| Somchem S365 | <<locked>> | 80% | 27,731 psi | 43% | 2513 fps | 96% |
| Somchem S385 | <<locked>> | 98% | 47,543 psi | 75% | 2917 fps | 95.9% |
| Vihtavuori N130 | <<locked>> | 80% | 53,635 psi | 84% | 2841 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 48,066 psi | 75% | 2772 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 43,830 psi | 69% | 2762 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 44,193 psi | 69% | 2766 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 36,187 psi | 57% | 2628 fps | 99% |
| Vihtavuori N160 | <<locked>> | 82% | 34,635 psi | 54% | 2635 fps | 95.3% |
| Vihtavuori N530 | <<locked>> | 80% | 49,719 psi | 78% | 2890 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 42,685 psi | 67% | 2756 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 36,448 psi | 57% | 2690 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 90% | 33,286 psi | 52% | 2677 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 32,082 psi | 50% | 2549 fps | 96.7% |
| Winchester 748 | <<locked>> | 80% | 49,748 psi | 78% | 2936 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 43,584 psi | 68% | 2871 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 92% | 28,848 psi | 45% | 2615 fps | 95% |
| Winchester StaBALL Match | <<locked>> | 80% | 45,629 psi | 72% | 2858 fps | 99.6% |
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 .308 Norma Mag. loaded with the .308 | 155gr | Merlin Virtus. ReloadSwiss RS 70 delivers the highest muzzle velocity at 3,173 fps; across all powders the maximum-charge window runs from 1,873 fps to 3,173 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 155.0 gr projectile in 0.308" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-23, Alliant Reloder-26 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 70, Hodgdon Superformance, ReloadSwiss RS 60 rank at the top here: for .308 Norma Mag. with the .308 | 155gr | Merlin Virtus 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.