Load Specifications
Load data in caliber .300 RCM with .308 | 180gr | Winchester FailSafe 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 Alliant Reloder-17.
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% | 56,101 psi | 88% | 2635 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 55,158 psi | 86% | 2667 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 56,666 psi | 89% | 2726 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 57,653 psi | 90% | 2720 fps | 97.9% |
| Accurate 3100ᴾ | <<locked>> | 100% | 41,901 psi | 66% | 2572 fps | 96.6% |
| Accurate 4064 | <<locked>> | 90% | 54,984 psi | 86% | 2713 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 54,723 psi | 86% | 2795 fps | 99.8% |
| ADI AR 2206H | <<locked>> | 86% | 55,332 psi | 87% | 2743 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 56,420 psi | 88% | 2743 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 84% | 54,230 psi | 85% | 2694 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 55,332 psi | 87% | 2667 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 54,998 psi | 86% | 2861 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 56,521 psi | 89% | 2766 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 57,058 psi | 89% | 2785 fps | 100% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 56,028 psi | 88% | 2854 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 96% | 57,305 psi | 90% | 2887 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 40,016 psi | 63% | 2602 fps | 99.3% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 44,657 psi | 70% | 2759 fps | 98.7% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 55,129 psi | 86% | 2759 fps | 99.8% |
| Bofors RP3 | <<locked>> | 92% | 57,261 psi | 90% | 2782 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 57,116 psi | 90% | 2756 fps | 98.1% |
| Hodgdon Benchmark | <<locked>> | 84% | 56,086 psi | 88% | 2677 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 57,246 psi | 90% | 2772 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 55,579 psi | 87% | 2818 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 54,346 psi | 85% | 2743 fps | 99.5% |
| Hodgdon H414 | <<locked>> | 98% | 57,566 psi | 90% | 2848 fps | 98.7% |
| Hodgdon H4350 | <<locked>> | 94% | 54,505 psi | 85% | 2756 fps | 97.1% |
| Hodgdon H4895 | <<locked>> | 86% | 55,883 psi | 88% | 2753 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 52,272 psi | 82% | 2730 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 55,303 psi | 87% | 2785 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 54,404 psi | 85% | 2828 fps | 97.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,679 psi | 56% | 1657 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 57,014 psi | 89% | 2753 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 56,057 psi | 88% | 2733 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 55,811 psi | 87% | 2726 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 88% | 55,695 psi | 87% | 2707 fps | 98.3% |
| IMR 4350ᴾ | <<locked>> | 100% | 57,319 psi | 90% | 2779 fps | 98.1% |
| IMR 4451 Enduron | <<locked>> | 94% | 55,550 psi | 87% | 2736 fps | 98.2% |
| IMR 4831ᴾ | <<locked>> | 100% | 55,216 psi | 87% | 2785 fps | 99.8% |
| IMR 4895 | <<locked>> | 88% | 54,911 psi | 86% | 2766 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 54,230 psi | 85% | 2694 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 55,274 psi | 87% | 2720 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 54,781 psi | 86% | 2671 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 55,593 psi | 87% | 2720 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 54,853 psi | 86% | 2726 fps | 99.1% |
| Lovex S070 | <<locked>> | 98% | 55,840 psi | 88% | 2762 fps | 98.6% |
| Norma 201 | <<locked>> | 88% | 57,638 psi | 90% | 2736 fps | 100% |
| Norma 202 | <<locked>> | 86% | 54,679 psi | 86% | 2690 fps | 100% |
| Norma 203B | <<locked>> | 90% | 56,217 psi | 88% | 2776 fps | 100% |
| Norma 204 | <<locked>> | 98% | 54,346 psi | 85% | 2776 fps | 96.4% |
| Norma MRPᴾ | <<locked>> | 100% | 44,788 psi | 70% | 2717 fps | 96.1% |
| Norma URPᴾ | <<locked>> | 100% | 57,435 psi | 90% | 2838 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 90% | 56,956 psi | 89% | 2802 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 56,014 psi | 88% | 2831 fps | 99.1% |
| Ramshot TAC | <<locked>> | 84% | 54,389 psi | 85% | 2713 fps | 99.2% |
| Ramshot Wild Boar | <<locked>> | 84% | 54,056 psi | 85% | 2730 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 55,027 psi | 86% | 2694 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,216 psi | 57% | 1699 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 57,246 psi | 90% | 2720 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 54,621 psi | 86% | 2726 fps | 98.7% |
| ReloadSwiss RS 52 | <<locked>> | 88% | 57,725 psi | 90% | 2854 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 94% | 57,130 psi | 90% | 2884 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 54,389 psi | 85% | 2818 fps | 99.7% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 53,896 psi | 84% | 2848 fps | 99.6% |
| Rottweil R 901 | <<locked>> | 84% | 55,056 psi | 86% | 2667 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 54,563 psi | 86% | 2687 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 56,840 psi | 89% | 2769 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 57,116 psi | 90% | 2756 fps | 98.1% |
| Shooters World Long Rifle | <<locked>> | 96% | 54,853 psi | 86% | 2726 fps | 99.1% |
| Shooters World Match Rifle | <<locked>> | 86% | 55,274 psi | 87% | 2720 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 55,593 psi | 87% | 2720 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 55,840 psi | 88% | 2762 fps | 98.6% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 54,969 psi | 86% | 2782 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 56,608 psi | 89% | 2746 fps | 99.6% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 57,276 psi | 90% | 2766 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 55,463 psi | 87% | 2628 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 55,767 psi | 87% | 2628 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 55,245 psi | 87% | 2684 fps | 98.2% |
| Somchem S321 | <<locked>> | 82% | 55,361 psi | 87% | 2723 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 54,955 psi | 86% | 2625 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 56,260 psi | 88% | 2736 fps | 100% |
| Somchem S355 | <<locked>> | 94% | 57,043 psi | 89% | 2766 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 51,779 psi | 81% | 2789 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 47,950 psi | 75% | 2671 fps | 96.4% |
| Vihtavuori N130 | <<locked>> | 82% | 55,317 psi | 87% | 2589 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 55,738 psi | 87% | 2608 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 54,288 psi | 85% | 2651 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 55,071 psi | 86% | 2667 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 55,013 psi | 86% | 2697 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 56,289 psi | 88% | 2779 fps | 99.8% |
| Vihtavuori N530 | <<locked>> | 84% | 54,853 psi | 86% | 2694 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 56,637 psi | 89% | 2710 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 55,347 psi | 87% | 2789 fps | 99.7% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 43,932 psi | 69% | 2674 fps | 99.2% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 56,463 psi | 88% | 2756 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 54,592 psi | 86% | 2736 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 54,186 psi | 85% | 2799 fps | 98.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 35,781 psi | 56% | 2608 fps | 99.3% |
| Winchester StaBALL Match | <<locked>> | 88% | 57,159 psi | 90% | 2772 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% | 49,806 psi | 78% | 2552 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 42,453 psi | 67% | 2484 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 49,487 psi | 78% | 2631 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 44,338 psi | 69% | 2510 fps | 95.1% |
| Accurate 3100 | <<locked>> | 98% | 39,117 psi | 61% | 2516 fps | 95.8% |
| Accurate 4064 | <<locked>> | 80% | 40,161 psi | 63% | 2484 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 31,517 psi | 49% | 2365 fps | 95.1% |
| ADI AR 2206H | <<locked>> | 80% | 45,759 psi | 72% | 2592 fps | 99.6% |
| ADI AR 2208 | <<locked>> | 80% | 38,870 psi | 61% | 2448 fps | 98% |
| ADI Benchmark 8208 | <<locked>> | 80% | 47,805 psi | 75% | 2595 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 48,501 psi | 76% | 2579 fps | 100% |
| Alliant Power Pro 2000-MR | 50.5 gr | 80% | 41,684 psi | 65% | 2628 fps | 98.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 38,798 psi | 61% | 2474 fps | 99.2% |
| Alliant Reloder-15 | <<locked>> | 80% | 41,423 psi | 65% | 2530 fps | 98.7% |
| Alliant Reloder-16 | <<locked>> | 82% | 32,126 psi | 50% | 2382 fps | 95.2% |
| Alliant Reloder-17 | 49.8 gr | 80% | 33,504 psi | 53% | 2448 fps | 97.7% |
| Alliant Reloder-23 | <<locked>> | 90% | 29,472 psi | 46% | 2343 fps | 95.8% |
| Alliant Reloder-26 | <<locked>> | 92% | 33,779 psi | 53% | 2510 fps | 95.1% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 45,194 psi | 71% | 2602 fps | 98.9% |
| Bofors RP3 | <<locked>> | 80% | 38,551 psi | 60% | 2480 fps | 99.2% |
| Bofors RP7 | <<locked>> | 88% | 44,483 psi | 70% | 2549 fps | 95.5% |
| Hodgdon Benchmark | <<locked>> | 80% | 49,516 psi | 78% | 2582 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 46,789 psi | 73% | 2618 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 51,808 psi | 81% | 2762 fps | 99.8% |
| Hodgdon H380 | <<locked>> | 80% | 39,262 psi | 62% | 2480 fps | 97.1% |
| Hodgdon H414 | <<locked>> | 88% | 41,336 psi | 65% | 2575 fps | 95.4% |
| Hodgdon H4350 | <<locked>> | 90% | 48,283 psi | 76% | 2654 fps | 95.7% |
| Hodgdon H4895 | <<locked>> | 80% | 46,180 psi | 72% | 2602 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 27,586 psi | 43% | 2234 fps | 95.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 42,438 psi | 67% | 2579 fps | 99.7% |
| Hodgdon Superformance | 59.2 gr | 90% | 44,092 psi | 69% | 2651 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,585 psi | 42% | 1480 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 44,396 psi | 70% | 2556 fps | 99.6% |
| IMR 3031 | <<locked>> | 80% | 46,021 psi | 72% | 2592 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 40,828 psi | 64% | 2477 fps | 98.6% |
| IMR 4166 Enduron | <<locked>> | 80% | 43,366 psi | 68% | 2500 fps | 95.8% |
| IMR 4350 | <<locked>> | 92% | 44,773 psi | 70% | 2579 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 84% | 40,857 psi | 64% | 2480 fps | 95% |
| IMR 4831 | <<locked>> | 84% | 32,837 psi | 51% | 2382 fps | 95.7% |
| IMR 4895 | <<locked>> | 80% | 42,453 psi | 67% | 2559 fps | 99.2% |
| IMR 8208 XBR | <<locked>> | 80% | 47,805 psi | 75% | 2595 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 45,165 psi | 71% | 2572 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 45,832 psi | 72% | 2533 fps | 99.6% |
| Lovex S062 | <<locked>> | 80% | 41,046 psi | 64% | 2487 fps | 99.7% |
| Lovex S065 | <<locked>> | 82% | 35,839 psi | 56% | 2382 fps | 95% |
| Lovex S070 | <<locked>> | 88% | 40,886 psi | 64% | 2510 fps | 95.4% |
| Norma 201 | <<locked>> | 80% | 44,933 psi | 70% | 2546 fps | 99.9% |
| Norma 202 | <<locked>> | 80% | 45,339 psi | 71% | 2552 fps | 100% |
| Norma 203B | <<locked>> | 80% | 40,814 psi | 64% | 2520 fps | 98.9% |
| Norma 204 | <<locked>> | 96% | 50,879 psi | 80% | 2720 fps | 95.7% |
| Norma MRP | <<locked>> | 98% | 41,727 psi | 65% | 2657 fps | 95.1% |
| Norma URP | <<locked>> | 82% | 31,995 psi | 50% | 2369 fps | 95% |
| Ramshot Big Game | <<locked>> | 80% | 40,408 psi | 63% | 2533 fps | 98.8% |
| Ramshot Hunter | <<locked>> | 88% | 37,985 psi | 60% | 2513 fps | 95.2% |
| Ramshot TAC | <<locked>> | 80% | 47,906 psi | 75% | 2608 fps | 98.3% |
| Ramshot Wild Boar | <<locked>> | 80% | 47,413 psi | 74% | 2625 fps | 99.7% |
| Ramshot X-Terminator | <<locked>> | 80% | 51,517 psi | 81% | 2644 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,934 psi | 42% | 1516 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 53,708 psi | 84% | 2674 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 39,479 psi | 62% | 2461 fps | 95.4% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 43,918 psi | 69% | 2635 fps | 99.1% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 35,650 psi | 56% | 2510 fps | 99.8% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 33,576 psi | 53% | 2438 fps | 95.5% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 35,926 psi | 56% | 2493 fps | 95.4% |
| Rottweil R 901 | <<locked>> | 80% | 49,023 psi | 77% | 2582 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,714 psi | 67% | 2500 fps | 99.8% |
| Rottweil R 903 | <<locked>> | 80% | 36,143 psi | 57% | 2425 fps | 98.6% |
| Rottweil R 907 | <<locked>> | 88% | 44,483 psi | 70% | 2549 fps | 95.5% |
| Shooters World Long Rifle | <<locked>> | 82% | 35,839 psi | 56% | 2382 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 45,165 psi | 71% | 2572 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 41,046 psi | 64% | 2487 fps | 99.7% |
| Shooters World SW4350 | <<locked>> | 88% | 40,886 psi | 64% | 2510 fps | 95.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 37,086 psi | 58% | 2470 fps | 98.1% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 46,209 psi | 72% | 2585 fps | 98.5% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 44,324 psi | 69% | 2566 fps | 99.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 46,296 psi | 73% | 2497 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,624 psi | 61% | 2372 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 42,583 psi | 67% | 2480 fps | 95.7% |
| Somchem S321 | <<locked>> | 80% | 52,025 psi | 82% | 2674 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 45,803 psi | 72% | 2497 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 46,006 psi | 72% | 2582 fps | 99.5% |
| Somchem S355 | <<locked>> | 80% | 36,927 psi | 58% | 2428 fps | 98.5% |
| Somchem S365 | <<locked>> | 80% | 26,934 psi | 42% | 2270 fps | 96.5% |
| Somchem S385 | <<locked>> | 98% | 44,904 psi | 70% | 2618 fps | 95.6% |
| Vihtavuori N130 | <<locked>> | 80% | 52,156 psi | 82% | 2549 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 46,659 psi | 73% | 2487 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 42,438 psi | 67% | 2480 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 42,830 psi | 67% | 2487 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 35,099 psi | 55% | 2365 fps | 99.1% |
| Vihtavuori N160 | <<locked>> | 82% | 33,344 psi | 52% | 2372 fps | 95.5% |
| Vihtavuori N530 | <<locked>> | 80% | 48,167 psi | 75% | 2595 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 41,336 psi | 65% | 2480 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 32,909 psi | 52% | 2372 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 88% | 29,820 psi | 47% | 2365 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 31,169 psi | 49% | 2300 fps | 97% |
| Winchester 748 | <<locked>> | 80% | 47,950 psi | 75% | 2641 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 41,568 psi | 65% | 2579 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 92% | 27,702 psi | 43% | 2359 fps | 95.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 43,816 psi | 69% | 2569 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 117 powders for .300 RCM loaded with the .308 | 180gr | Winchester FailSafe. Alliant Reloder-17 delivers the highest muzzle velocity at 2,887 fps; across all powders the maximum-charge window runs from 1,657 fps to 2,887 fps. Accurate 3100 gives the best case fill at 100 %, and 117 of the 117 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 55–90 %, 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, ADI AR 2209, ADI AR 2213 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, Alliant Reloder-17 rank at the top here: for .300 RCM with the .308 | 180gr | Winchester FailSafe they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2213, Alliant Reloder-22, Alliant Reloder-25 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.