Load Specifications
Load data in caliber .300 RCM with .308 | 180gr | Sellier & Bellot FMJ-BT bullet and 99 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Power Pro 2000-MR, 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>> | 84% | 56,971 psi | 89% | 2651 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 55,782 psi | 87% | 2677 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 57,508 psi | 90% | 2743 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 54,752 psi | 86% | 2687 fps | 97.5% |
| Accurate 3100ᴾ | <<locked>> | 100% | 42,757 psi | 67% | 2592 fps | 97% |
| Accurate 4064 | <<locked>> | 90% | 55,854 psi | 88% | 2726 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 55,767 psi | 87% | 2818 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 86% | 56,086 psi | 88% | 2759 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 56,840 psi | 89% | 2756 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 84% | 55,027 psi | 86% | 2710 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 55,956 psi | 88% | 2677 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 55,680 psi | 87% | 2877 fps | 100% |
| Alliant Power Pro Varmintᴾ | <<locked>> | 100% | 50,227 psi | 79% | 2736 fps | 95.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 57,261 psi | 90% | 2779 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 54,317 psi | 85% | 2753 fps | 100% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 56,681 psi | 89% | 2867 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 94% | 54,259 psi | 85% | 2851 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 40,770 psi | 64% | 2621 fps | 99.4% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 45,629 psi | 72% | 2782 fps | 98.9% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 55,796 psi | 87% | 2776 fps | 99.9% |
| Bofors RP3 | <<locked>> | 90% | 54,099 psi | 85% | 2746 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 57,711 psi | 90% | 2769 fps | 98.2% |
| Hodgdon Benchmark | <<locked>> | 84% | 56,565 psi | 89% | 2690 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 54,186 psi | 85% | 2736 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 56,405 psi | 88% | 2835 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 55,027 psi | 86% | 2759 fps | 99.6% |
| Hodgdon H414 | <<locked>> | 96% | 54,853 psi | 86% | 2815 fps | 98.5% |
| Hodgdon H4350 | <<locked>> | 94% | 55,434 psi | 87% | 2776 fps | 97.3% |
| Hodgdon H4895 | <<locked>> | 86% | 56,637 psi | 89% | 2766 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 52,939 psi | 83% | 2746 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 56,043 psi | 88% | 2799 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 55,187 psi | 86% | 2848 fps | 98.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,607 psi | 56% | 1663 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 54,259 psi | 85% | 2720 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 56,695 psi | 89% | 2743 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 56,565 psi | 89% | 2743 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 88% | 56,376 psi | 88% | 2723 fps | 98.5% |
| IMR 4350 | <<locked>> | 98% | 54,404 psi | 85% | 2743 fps | 97.8% |
| IMR 4451 Enduron | <<locked>> | 94% | 56,144 psi | 88% | 2749 fps | 98.4% |
| IMR 4831ᴾ | <<locked>> | 100% | 56,144 psi | 88% | 2805 fps | 99.9% |
| IMR 4895 | <<locked>> | 88% | 55,709 psi | 87% | 2782 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 55,027 psi | 86% | 2710 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 55,796 psi | 87% | 2733 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 55,477 psi | 87% | 2687 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 56,362 psi | 88% | 2736 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 55,521 psi | 87% | 2743 fps | 99.3% |
| Lovex S070 | <<locked>> | 98% | 56,434 psi | 88% | 2779 fps | 98.7% |
| Norma 201 | <<locked>> | 86% | 54,621 psi | 86% | 2700 fps | 100% |
| Norma 202 | <<locked>> | 86% | 55,230 psi | 87% | 2703 fps | 100% |
| Norma 203B | <<locked>> | 90% | 56,985 psi | 89% | 2789 fps | 100% |
| Norma 204 | <<locked>> | 98% | 55,158 psi | 86% | 2795 fps | 96.7% |
| Norma MRPᴾ | <<locked>> | 100% | 45,498 psi | 71% | 2736 fps | 96.5% |
| Norma URP | <<locked>> | 98% | 54,505 psi | 85% | 2799 fps | 99.8% |
| Ramshot Big Game | <<locked>> | 90% | 57,667 psi | 90% | 2815 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 56,826 psi | 89% | 2851 fps | 99.3% |
| Ramshot TAC | <<locked>> | 84% | 55,042 psi | 86% | 2730 fps | 99.3% |
| Ramshot Wild Boar | <<locked>> | 84% | 54,781 psi | 86% | 2746 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 55,709 psi | 87% | 2710 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,129 psi | 57% | 1703 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 55,259 psi | 87% | 2740 fps | 98.8% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 54,534 psi | 85% | 2815 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 54,186 psi | 85% | 2851 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 55,347 psi | 87% | 2838 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 54,679 psi | 86% | 2864 fps | 99.7% |
| Rottweil R 901 | <<locked>> | 84% | 55,608 psi | 87% | 2680 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 55,347 psi | 87% | 2703 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 54,259 psi | 85% | 2740 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 57,711 psi | 90% | 2769 fps | 98.2% |
| Shooters World Long Rifle | <<locked>> | 96% | 55,521 psi | 87% | 2743 fps | 99.3% |
| Shooters World Match Rifle | <<locked>> | 86% | 55,796 psi | 87% | 2733 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 56,362 psi | 88% | 2736 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 56,434 psi | 88% | 2779 fps | 98.7% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 55,927 psi | 88% | 2799 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 57,290 psi | 90% | 2759 fps | 99.7% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 54,244 psi | 85% | 2730 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 56,289 psi | 88% | 2644 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 56,536 psi | 89% | 2641 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 55,854 psi | 88% | 2697 fps | 98.4% |
| Somchem S321 | <<locked>> | 82% | 56,130 psi | 88% | 2740 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 55,434 psi | 87% | 2638 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 56,927 psi | 89% | 2749 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 54,549 psi | 85% | 2736 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 52,446 psi | 82% | 2802 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 48,776 psi | 76% | 2690 fps | 96.7% |
| Vihtavuori N130 | <<locked>> | 82% | 55,898 psi | 88% | 2602 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 56,550 psi | 89% | 2625 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 55,143 psi | 86% | 2664 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 55,840 psi | 88% | 2684 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 55,999 psi | 88% | 2717 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 57,246 psi | 90% | 2799 fps | 99.9% |
| Vihtavuori N530 | <<locked>> | 84% | 55,376 psi | 87% | 2707 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 57,305 psi | 90% | 2723 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 55,970 psi | 88% | 2802 fps | 99.8% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 44,846 psi | 70% | 2694 fps | 99.3% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 57,217 psi | 90% | 2772 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 55,376 psi | 87% | 2753 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 54,853 psi | 86% | 2815 fps | 98.5% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 36,376 psi | 57% | 2631 fps | 99.5% |
| Winchester StaBALL Match | <<locked>> | 86% | 54,346 psi | 85% | 2740 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% | 50,415 psi | 79% | 2566 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 43,033 psi | 67% | 2500 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 50,328 psi | 79% | 2648 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 44,962 psi | 70% | 2526 fps | 95.4% |
| Accurate 3100 | <<locked>> | 96% | 37,289 psi | 58% | 2487 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 40,727 psi | 64% | 2497 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 32,184 psi | 50% | 2385 fps | 95.5% |
| ADI AR 2206H | <<locked>> | 80% | 46,485 psi | 73% | 2608 fps | 99.7% |
| ADI AR 2208 | <<locked>> | 80% | 39,349 psi | 62% | 2461 fps | 98.2% |
| ADI Benchmark 8208 | <<locked>> | 80% | 48,588 psi | 76% | 2612 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 49,168 psi | 77% | 2592 fps | 100% |
| Alliant Power Pro 2000-MR | 51.2 gr | 80% | 42,308 psi | 66% | 2648 fps | 98.8% |
| Alliant Power Pro Varmint | <<locked>> | 98% | 47,123 psi | 74% | 2680 fps | 95% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 39,276 psi | 62% | 2487 fps | 99.3% |
| Alliant Reloder-15 | <<locked>> | 80% | 42,177 psi | 66% | 2549 fps | 98.9% |
| Alliant Reloder-16 | <<locked>> | 82% | 32,489 psi | 51% | 2398 fps | 95.5% |
| Alliant Reloder-17 | <<locked>> | 80% | 33,881 psi | 53% | 2461 fps | 97.9% |
| Alliant Reloder-23 | <<locked>> | 88% | 28,123 psi | 44% | 2306 fps | 95.2% |
| Alliant Reloder-26 | <<locked>> | 92% | 34,403 psi | 54% | 2533 fps | 95.5% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 45,643 psi | 72% | 2615 fps | 99% |
| Bofors RP3 | <<locked>> | 80% | 39,015 psi | 61% | 2493 fps | 99.3% |
| Bofors RP7 | <<locked>> | 86% | 42,351 psi | 66% | 2516 fps | 95% |
| Hodgdon Benchmark | <<locked>> | 80% | 50,009 psi | 78% | 2595 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 47,529 psi | 74% | 2638 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 52,591 psi | 82% | 2779 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 80% | 39,740 psi | 62% | 2497 fps | 97.3% |
| Hodgdon H414 | <<locked>> | 88% | 41,959 psi | 66% | 2592 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 88% | 45,701 psi | 72% | 2615 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 46,963 psi | 74% | 2618 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 27,978 psi | 44% | 2251 fps | 95.5% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 42,917 psi | 67% | 2592 fps | 99.8% |
| Hodgdon Superformance | 59.9 gr | 90% | 44,570 psi | 70% | 2664 fps | 95.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,614 psi | 42% | 1486 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 44,875 psi | 70% | 2569 fps | 99.7% |
| IMR 3031 | <<locked>> | 80% | 46,659 psi | 73% | 2605 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 41,336 psi | 65% | 2493 fps | 98.8% |
| IMR 4166 Enduron | <<locked>> | 80% | 43,801 psi | 69% | 2516 fps | 96% |
| IMR 4350 | <<locked>> | 90% | 42,598 psi | 67% | 2543 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 84% | 41,466 psi | 65% | 2500 fps | 95.3% |
| IMR 4831 | <<locked>> | 82% | 31,154 psi | 49% | 2343 fps | 95.1% |
| IMR 4895 | <<locked>> | 80% | 43,221 psi | 68% | 2579 fps | 99.4% |
| IMR 8208 XBR | <<locked>> | 80% | 48,588 psi | 76% | 2612 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 45,716 psi | 72% | 2585 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 46,108 psi | 72% | 2539 fps | 99.6% |
| Lovex S062 | <<locked>> | 80% | 41,307 psi | 65% | 2497 fps | 99.7% |
| Lovex S065 | <<locked>> | 82% | 36,260 psi | 57% | 2398 fps | 95.3% |
| Lovex S070 | <<locked>> | 88% | 41,510 psi | 65% | 2526 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 45,455 psi | 71% | 2559 fps | 100% |
| Norma 202 | <<locked>> | 80% | 45,876 psi | 72% | 2566 fps | 100% |
| Norma 203B | <<locked>> | 80% | 41,553 psi | 65% | 2539 fps | 99.1% |
| Norma 204 | <<locked>> | 94% | 48,211 psi | 76% | 2684 fps | 95.2% |
| Norma MRP | <<locked>> | 98% | 42,438 psi | 67% | 2677 fps | 95.5% |
| Norma URP | <<locked>> | 82% | 32,445 psi | 51% | 2385 fps | 95.3% |
| Ramshot Big Game | <<locked>> | 80% | 41,075 psi | 64% | 2552 fps | 98.9% |
| Ramshot Hunter | <<locked>> | 88% | 38,522 psi | 60% | 2530 fps | 95.5% |
| Ramshot TAC | <<locked>> | 80% | 48,298 psi | 76% | 2621 fps | 98.5% |
| Ramshot Wild Boar | <<locked>> | 80% | 47,863 psi | 75% | 2638 fps | 99.8% |
| Ramshot X-Terminator | <<locked>> | 80% | 52,199 psi | 82% | 2661 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,977 psi | 42% | 1522 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 40,103 psi | 63% | 2480 fps | 95.7% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 44,454 psi | 70% | 2648 fps | 99.2% |
| ReloadSwiss RS 60 | 50.4 gr | 80% | 36,027 psi | 56% | 2523 fps | 99.9% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 34,156 psi | 54% | 2454 fps | 95.8% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 36,419 psi | 57% | 2513 fps | 95.8% |
| Rottweil R 901 | <<locked>> | 80% | 49,617 psi | 78% | 2595 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 43,192 psi | 68% | 2513 fps | 99.8% |
| Rottweil R 903 | <<locked>> | 80% | 36,622 psi | 57% | 2438 fps | 98.7% |
| Rottweil R 907 | <<locked>> | 86% | 42,351 psi | 66% | 2516 fps | 95% |
| Shooters World Long Rifle | <<locked>> | 82% | 36,260 psi | 57% | 2398 fps | 95.3% |
| Shooters World Match Rifle | <<locked>> | 80% | 45,716 psi | 72% | 2585 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 41,307 psi | 65% | 2497 fps | 99.7% |
| Shooters World SW4350 | <<locked>> | 88% | 41,510 psi | 65% | 2526 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 37,550 psi | 59% | 2487 fps | 98.3% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 46,862 psi | 73% | 2602 fps | 98.6% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 44,802 psi | 70% | 2579 fps | 99.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 46,572 psi | 73% | 2507 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,899 psi | 61% | 2379 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 40,451 psi | 63% | 2444 fps | 95.2% |
| Somchem S321 | <<locked>> | 80% | 52,446 psi | 82% | 2687 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 46,311 psi | 73% | 2510 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 46,456 psi | 73% | 2595 fps | 99.6% |
| Somchem S355 | <<locked>> | 80% | 37,405 psi | 59% | 2441 fps | 98.7% |
| Somchem S365 | <<locked>> | 80% | 27,296 psi | 43% | 2287 fps | 96.8% |
| Somchem S385 | <<locked>> | 96% | 42,830 psi | 67% | 2585 fps | 95.1% |
| Vihtavuori N130 | <<locked>> | 80% | 52,489 psi | 82% | 2556 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 46,963 psi | 74% | 2497 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 42,815 psi | 67% | 2490 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 43,323 psi | 68% | 2500 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 35,549 psi | 56% | 2379 fps | 99.2% |
| Vihtavuori N160 | <<locked>> | 80% | 31,821 psi | 50% | 2336 fps | 95% |
| Vihtavuori N530 | <<locked>> | 80% | 48,660 psi | 76% | 2608 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 41,814 psi | 66% | 2493 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 33,330 psi | 52% | 2388 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 88% | 30,211 psi | 47% | 2379 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 31,459 psi | 49% | 2313 fps | 97.2% |
| Winchester 748 | <<locked>> | 80% | 48,472 psi | 76% | 2654 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 42,192 psi | 66% | 2595 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 92% | 28,239 psi | 44% | 2382 fps | 95.8% |
| Winchester StaBALL Match | <<locked>> | 80% | 44,498 psi | 70% | 2585 fps | 99.7% |
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 99 powders for .300 RCM loaded with the .308 | 180gr | Sellier & Bellot FMJ-BT. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 2,877 fps; across all powders the maximum-charge window runs from 1,663 fps to 2,877 fps. Accurate 3100 gives the best case fill at 100 %, and 99 of the 99 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 180.0 gr projectile in 0.308" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Power Pro Varmint, Alliant Reloder-16 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. Alliant Power Pro 2000-MR, Hodgdon Superformance, ReloadSwiss RS 60 rank at the top here: for .300 RCM with the .308 | 180gr | Sellier & Bellot FMJ-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.