Load Specifications
Load data in caliber .300 RCM with .308 | 180gr | Sellier & Bellot XRG 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% | 55,927 psi | 88% | 2625 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 54,665 psi | 86% | 2651 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 56,376 psi | 88% | 2717 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 57,232 psi | 90% | 2703 fps | 97.7% |
| Accurate 3100ᴾ | <<locked>> | 100% | 41,466 psi | 65% | 2552 fps | 96.4% |
| Accurate 4064 | <<locked>> | 90% | 54,505 psi | 85% | 2697 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 53,969 psi | 85% | 2776 fps | 99.7% |
| ADI AR 2206H | <<locked>> | 86% | 54,969 psi | 86% | 2730 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 55,825 psi | 87% | 2726 fps | 99.9% |
| ADI Benchmark 8208 | <<locked>> | 86% | 57,363 psi | 90% | 2726 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 54,694 psi | 86% | 2651 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 54,375 psi | 85% | 2841 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 55,883 psi | 88% | 2749 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 56,420 psi | 88% | 2769 fps | 100% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 55,216 psi | 87% | 2831 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 96% | 56,550 psi | 89% | 2867 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 39,566 psi | 62% | 2582 fps | 99.1% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 44,280 psi | 69% | 2740 fps | 98.5% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 54,578 psi | 86% | 2743 fps | 99.8% |
| Bofors RP3 | <<locked>> | 92% | 56,434 psi | 88% | 2762 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 56,347 psi | 88% | 2733 fps | 97.8% |
| Hodgdon Benchmark | <<locked>> | 84% | 55,651 psi | 87% | 2661 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 56,695 psi | 89% | 2756 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 54,911 psi | 86% | 2802 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 92% | 57,435 psi | 90% | 2776 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 98% | 56,826 psi | 89% | 2825 fps | 98.5% |
| Hodgdon H4350 | <<locked>> | 96% | 57,595 psi | 90% | 2789 fps | 97.4% |
| Hodgdon H4895 | <<locked>> | 86% | 55,506 psi | 87% | 2736 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 51,503 psi | 81% | 2710 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 54,694 psi | 86% | 2769 fps | 100% |
| Hodgdon Superformance | <<locked>> | 98% | 57,638 psi | 90% | 2864 fps | 98.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,607 psi | 56% | 1647 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 56,652 psi | 89% | 2740 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 55,535 psi | 87% | 2717 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 55,477 psi | 87% | 2710 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 88% | 55,172 psi | 86% | 2687 fps | 98.1% |
| IMR 4350ᴾ | <<locked>> | 100% | 56,623 psi | 89% | 2759 fps | 97.9% |
| IMR 4451 Enduron | <<locked>> | 94% | 55,027 psi | 86% | 2717 fps | 98% |
| IMR 4831ᴾ | <<locked>> | 100% | 54,462 psi | 85% | 2769 fps | 99.8% |
| IMR 4895 | <<locked>> | 88% | 54,273 psi | 85% | 2746 fps | 100% |
| IMR 8208 XBR | <<locked>> | 86% | 57,363 psi | 90% | 2726 fps | 100% |
| Lovex D073.5 | <<locked>> | 82% | 57,711 psi | 90% | 2710 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 54,665 psi | 86% | 2703 fps | 100% |
| Lovex S060 | <<locked>> | 88% | 57,609 psi | 90% | 2700 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 55,288 psi | 87% | 2707 fps | 100% |
| Lovex S065 | <<locked>> | 98% | 57,711 psi | 90% | 2759 fps | 99.3% |
| Lovex S070 | <<locked>> | 98% | 55,158 psi | 86% | 2743 fps | 98.4% |
| Norma 201 | <<locked>> | 88% | 57,058 psi | 89% | 2720 fps | 100% |
| Norma 202 | <<locked>> | 88% | 57,624 psi | 90% | 2720 fps | 100% |
| Norma 203B | <<locked>> | 90% | 55,666 psi | 87% | 2756 fps | 100% |
| Norma 204ᴾ | <<locked>> | 100% | 57,464 psi | 90% | 2812 fps | 96.9% |
| Norma URPᴾ | <<locked>> | 100% | 56,681 psi | 89% | 2818 fps | 99.8% |
| Ramshot Big Game | <<locked>> | 90% | 56,115 psi | 88% | 2782 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 55,332 psi | 87% | 2812 fps | 98.9% |
| Ramshot TAC | <<locked>> | 86% | 57,682 psi | 90% | 2749 fps | 99.4% |
| Ramshot Wild Boar | <<locked>> | 86% | 57,276 psi | 90% | 2766 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 54,462 psi | 85% | 2677 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,172 psi | 57% | 1690 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 56,782 psi | 89% | 2703 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 92% | 57,696 psi | 90% | 2759 fps | 98.9% |
| ReloadSwiss RS 52 | <<locked>> | 88% | 57,000 psi | 89% | 2835 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 94% | 56,362 psi | 88% | 2867 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 57,493 psi | 90% | 2851 fps | 99.8% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 56,985 psi | 89% | 2881 fps | 99.7% |
| Rottweil R 901 | <<locked>> | 84% | 54,984 psi | 86% | 2657 fps | 100% |
| Rottweil R 902 | <<locked>> | 90% | 57,522 psi | 90% | 2717 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 56,289 psi | 88% | 2753 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 56,347 psi | 88% | 2733 fps | 97.8% |
| Shooters World Long Rifle | <<locked>> | 98% | 57,711 psi | 90% | 2759 fps | 99.3% |
| Shooters World Match Rifle | <<locked>> | 86% | 54,665 psi | 86% | 2703 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 55,288 psi | 87% | 2707 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 55,158 psi | 86% | 2743 fps | 98.4% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 54,462 psi | 85% | 2766 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 56,101 psi | 88% | 2730 fps | 99.5% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 56,681 psi | 89% | 2749 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 54,984 psi | 86% | 2612 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 55,143 psi | 86% | 2608 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 54,592 psi | 86% | 2664 fps | 98% |
| Somchem S321 | <<locked>> | 82% | 55,085 psi | 86% | 2710 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 54,621 psi | 86% | 2612 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 55,709 psi | 87% | 2720 fps | 100% |
| Somchem S355 | <<locked>> | 94% | 56,536 psi | 89% | 2749 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 51,024 psi | 80% | 2769 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 47,398 psi | 74% | 2651 fps | 96.1% |
| Vihtavuori N130 | <<locked>> | 82% | 54,752 psi | 86% | 2572 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 55,230 psi | 87% | 2595 fps | 100% |
| Vihtavuori N135 | <<locked>> | 90% | 57,203 psi | 90% | 2677 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 54,708 psi | 86% | 2654 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 54,476 psi | 85% | 2684 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 55,492 psi | 87% | 2759 fps | 99.7% |
| Vihtavuori N530 | <<locked>> | 84% | 54,157 psi | 85% | 2677 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 56,115 psi | 88% | 2697 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 54,708 psi | 86% | 2769 fps | 99.6% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 43,555 psi | 68% | 2657 fps | 99% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 55,956 psi | 88% | 2743 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 54,230 psi | 85% | 2723 fps | 100% |
| Winchester 760 | <<locked>> | 98% | 57,072 psi | 89% | 2831 fps | 98.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 35,520 psi | 56% | 2589 fps | 99.1% |
| Winchester StaBALL Match | <<locked>> | 88% | 56,594 psi | 89% | 2756 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% | 49,327 psi | 77% | 2536 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 42,424 psi | 66% | 2477 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 49,211 psi | 77% | 2615 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 47,007 psi | 74% | 2546 fps | 95.7% |
| Accurate 3100 | <<locked>> | 98% | 38,682 psi | 61% | 2500 fps | 95.5% |
| Accurate 4064 | <<locked>> | 80% | 40,118 psi | 63% | 2474 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 33,620 psi | 53% | 2408 fps | 95.8% |
| ADI AR 2206H | <<locked>> | 80% | 45,614 psi | 71% | 2579 fps | 99.5% |
| ADI AR 2208 | <<locked>> | 80% | 38,725 psi | 61% | 2434 fps | 97.8% |
| ADI Benchmark 8208 | <<locked>> | 80% | 47,645 psi | 75% | 2582 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 47,892 psi | 75% | 2562 fps | 100% |
| Alliant Power Pro 2000-MR | 49.6 gr | 80% | 41,365 psi | 65% | 2612 fps | 98.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 38,421 psi | 60% | 2457 fps | 99% |
| Alliant Reloder-15 | <<locked>> | 80% | 41,321 psi | 65% | 2520 fps | 98.6% |
| Alliant Reloder-16 | <<locked>> | 84% | 33,823 psi | 53% | 2418 fps | 95.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 33,098 psi | 52% | 2428 fps | 97.4% |
| Alliant Reloder-23 | <<locked>> | 90% | 29,254 psi | 46% | 2326 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 94% | 35,897 psi | 56% | 2556 fps | 95.8% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 44,628 psi | 70% | 2582 fps | 98.7% |
| Bofors RP3 | <<locked>> | 80% | 38,247 psi | 60% | 2464 fps | 99.1% |
| Bofors RP7 | <<locked>> | 88% | 44,251 psi | 69% | 2536 fps | 95.3% |
| Hodgdon Benchmark | <<locked>> | 80% | 49,342 psi | 77% | 2569 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 46,499 psi | 73% | 2605 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 51,401 psi | 81% | 2746 fps | 99.8% |
| Hodgdon H380 | <<locked>> | 80% | 39,001 psi | 61% | 2467 fps | 96.9% |
| Hodgdon H414 | <<locked>> | 88% | 41,133 psi | 64% | 2562 fps | 95.2% |
| Hodgdon H4350 | <<locked>> | 90% | 47,776 psi | 75% | 2635 fps | 95.4% |
| Hodgdon H4895 | <<locked>> | 80% | 46,006 psi | 72% | 2589 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 29,298 psi | 46% | 2274 fps | 95.9% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 41,814 psi | 66% | 2562 fps | 99.6% |
| Hodgdon Superformance | 58.1 gr | 90% | 43,569 psi | 68% | 2628 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,600 psi | 42% | 1473 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 44,019 psi | 69% | 2539 fps | 99.5% |
| IMR 3031 | <<locked>> | 80% | 45,701 psi | 72% | 2579 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 40,669 psi | 64% | 2467 fps | 98.5% |
| IMR 4166 Enduron | <<locked>> | 80% | 43,062 psi | 67% | 2484 fps | 95.6% |
| IMR 4350 | <<locked>> | 92% | 44,353 psi | 70% | 2562 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 86% | 43,221 psi | 68% | 2516 fps | 95.5% |
| IMR 4831 | <<locked>> | 84% | 32,648 psi | 51% | 2369 fps | 95.5% |
| IMR 4895 | <<locked>> | 80% | 42,308 psi | 66% | 2546 fps | 99.1% |
| IMR 8208 XBR | <<locked>> | 80% | 47,645 psi | 75% | 2582 fps | 100% |
| Lovex D073.5 | <<locked>> | 80% | 54,099 psi | 85% | 2664 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 44,860 psi | 70% | 2559 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 45,440 psi | 71% | 2513 fps | 99.5% |
| Lovex S062 | <<locked>> | 80% | 40,712 psi | 64% | 2470 fps | 99.6% |
| Lovex S065 | <<locked>> | 84% | 37,768 psi | 59% | 2415 fps | 95.5% |
| Lovex S070 | <<locked>> | 88% | 40,683 psi | 64% | 2493 fps | 95.2% |
| Norma 201 | <<locked>> | 80% | 44,773 psi | 70% | 2533 fps | 99.9% |
| Norma 202 | <<locked>> | 80% | 44,918 psi | 70% | 2536 fps | 100% |
| Norma 203B | <<locked>> | 80% | 40,669 psi | 64% | 2507 fps | 98.8% |
| Norma 204 | <<locked>> | 96% | 50,256 psi | 79% | 2700 fps | 95.3% |
| Norma URP | <<locked>> | 84% | 33,997 psi | 53% | 2408 fps | 95.7% |
| Ramshot Big Game | <<locked>> | 80% | 40,089 psi | 63% | 2520 fps | 98.6% |
| Ramshot Hunter | <<locked>> | 90% | 40,132 psi | 63% | 2549 fps | 95.8% |
| Ramshot TAC | <<locked>> | 80% | 47,413 psi | 74% | 2592 fps | 98.1% |
| Ramshot Wild Boar | <<locked>> | 80% | 47,123 psi | 74% | 2612 fps | 99.6% |
| Ramshot X-Terminator | <<locked>> | 80% | 51,184 psi | 80% | 2628 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,963 psi | 42% | 1509 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 53,287 psi | 84% | 2657 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 39,204 psi | 61% | 2444 fps | 95.1% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 43,453 psi | 68% | 2618 fps | 98.9% |
| ReloadSwiss RS 60 | 48.8 gr | 80% | 35,230 psi | 55% | 2490 fps | 99.7% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 33,243 psi | 52% | 2418 fps | 95.1% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 35,636 psi | 56% | 2477 fps | 95.1% |
| Rottweil R 901 | <<locked>> | 80% | 48,646 psi | 76% | 2566 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,569 psi | 67% | 2487 fps | 99.7% |
| Rottweil R 903 | <<locked>> | 80% | 36,042 psi | 56% | 2411 fps | 98.4% |
| Rottweil R 907 | <<locked>> | 88% | 44,251 psi | 69% | 2536 fps | 95.3% |
| Shooters World Long Rifle | <<locked>> | 84% | 37,768 psi | 59% | 2415 fps | 95.5% |
| Shooters World Match Rifle | <<locked>> | 80% | 44,860 psi | 70% | 2559 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 40,712 psi | 64% | 2470 fps | 99.6% |
| Shooters World SW4350 | <<locked>> | 88% | 40,683 psi | 64% | 2493 fps | 95.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 36,825 psi | 58% | 2457 fps | 97.9% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 45,948 psi | 72% | 2569 fps | 98.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 43,976 psi | 69% | 2549 fps | 99.3% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 45,803 psi | 72% | 2480 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,189 psi | 60% | 2356 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 42,163 psi | 66% | 2461 fps | 95.4% |
| Somchem S321 | <<locked>> | 80% | 51,401 psi | 81% | 2657 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 45,658 psi | 72% | 2484 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 45,484 psi | 71% | 2562 fps | 99.4% |
| Somchem S355 | <<locked>> | 80% | 36,854 psi | 58% | 2418 fps | 98.4% |
| Somchem S365 | <<locked>> | 80% | 26,760 psi | 42% | 2257 fps | 96.2% |
| Somchem S385 | <<locked>> | 98% | 44,643 psi | 70% | 2605 fps | 95.4% |
| Vihtavuori N130 | <<locked>> | 80% | 51,634 psi | 81% | 2533 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 46,151 psi | 72% | 2470 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 41,945 psi | 66% | 2464 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 42,627 psi | 67% | 2477 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 35,012 psi | 55% | 2356 fps | 99% |
| Vihtavuori N160 | <<locked>> | 82% | 33,098 psi | 52% | 2356 fps | 95.3% |
| Vihtavuori N530 | <<locked>> | 80% | 47,747 psi | 75% | 2579 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 41,031 psi | 64% | 2467 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 34,925 psi | 55% | 2411 fps | 95.8% |
| Vihtavuori N555 | <<locked>> | 90% | 31,531 psi | 49% | 2402 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 30,908 psi | 48% | 2283 fps | 96.7% |
| Winchester 748 | <<locked>> | 80% | 47,268 psi | 74% | 2621 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 41,133 psi | 64% | 2562 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 94% | 29,385 psi | 46% | 2405 fps | 96.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 43,453 psi | 68% | 2552 fps | 99.5% |
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 XRG. ReloadSwiss RS 70 delivers the highest muzzle velocity at 2,881 fps; across all powders the maximum-charge window runs from 1,647 fps to 2,881 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 1:12.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-16, Alliant Reloder-23 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 XRG 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.