Load Specifications
Load data in caliber .300 RCM with .308 | 146gr | Peregrine Glider (Glider GRM) bullet and 95 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, ReloadSwiss RS 52 and Hodgdon LEVERevolution.
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.
A valid access license is required to use the Personalized Load Calculator.
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>> | 90% | 56,695 psi | 89% | 2943 fps | 100% |
| Accurate 2200 | <<locked>> | 82% | 56,942 psi | 89% | 3048 fps | 99% |
| Accurate 2460 | <<locked>> | 86% | 55,216 psi | 87% | 2966 fps | 100% |
| Accurate 2495 | <<locked>> | 96% | 57,421 psi | 90% | 3002 fps | 100% |
| Accurate 2520 | <<locked>> | 90% | 57,058 psi | 89% | 3031 fps | 100% |
| Accurate 4064 | <<locked>> | 98% | 57,174 psi | 90% | 3045 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 45,861 psi | 72% | 2930 fps | 96.9% |
| Accurate LT-30 | <<locked>> | 84% | 56,550 psi | 89% | 2890 fps | 100% |
| Accurate LT-32 | <<locked>> | 84% | 57,000 psi | 89% | 2917 fps | 100% |
| ADI AR 2206H | <<locked>> | 92% | 55,898 psi | 88% | 3035 fps | 99.4% |
| ADI AR 2208 | <<locked>> | 98% | 56,811 psi | 89% | 3028 fps | 99.1% |
| ADI AR 2219 | <<locked>> | 84% | 57,595 psi | 90% | 3018 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 90% | 55,143 psi | 86% | 2992 fps | 99.8% |
| Alliant AR-Comp | <<locked>> | 90% | 54,737 psi | 86% | 2969 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 86% | 56,608 psi | 89% | 3104 fps | 99.8% |
| Alliant Power Pro 2000-MR | <<locked>> | 94% | 55,579 psi | 87% | 3150 fps | 99% |
| Alliant Reloder- TS 15.5 | <<locked>> | 98% | 56,101 psi | 88% | 3048 fps | 99.8% |
| Alliant Reloder-10x | <<locked>> | 86% | 56,318 psi | 88% | 2949 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 96% | 56,869 psi | 89% | 3071 fps | 99.2% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 46,021 psi | 72% | 2943 fps | 97.1% |
| Alliant Reloder-17ᴾ | <<locked>> | 100% | 53,316 psi | 84% | 3110 fps | 99.6% |
| Baschieri & Pellagri 106 | <<locked>> | 84% | 55,767 psi | 87% | 2884 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 92% | 55,767 psi | 87% | 3045 fps | 98.8% |
| Bofors RP3 | <<locked>> | 98% | 56,666 psi | 89% | 3068 fps | 99.9% |
| Hodgdon Benchmark | <<locked>> | 90% | 57,377 psi | 90% | 2979 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 92% | 57,725 psi | 90% | 3074 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 88% | 55,970 psi | 88% | 3117 fps | 99.2% |
| Hodgdon H322 | <<locked>> | 86% | 55,985 psi | 88% | 2995 fps | 100% |
| Hodgdon H335 | <<locked>> | 86% | 57,159 psi | 90% | 3022 fps | 100% |
| Hodgdon H380 | <<locked>> | 96% | 54,534 psi | 85% | 3018 fps | 98% |
| Hodgdon H4895 | <<locked>> | 92% | 56,391 psi | 88% | 3048 fps | 99.7% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 41,974 psi | 66% | 2818 fps | 97.6% |
| Hodgdon LEVERevolution | <<locked>> | 94% | 55,071 psi | 86% | 3074 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,548 psi | 54% | 1824 fps | 100% |
| Hodgdon VARGET | <<locked>> | 92% | 54,389 psi | 85% | 2999 fps | 99.5% |
| IMR 3031 | <<locked>> | 92% | 55,419 psi | 87% | 3035 fps | 100% |
| IMR 4064 | <<locked>> | 96% | 56,376 psi | 88% | 3012 fps | 99.2% |
| IMR 4166 Enduron | <<locked>> | 94% | 57,188 psi | 90% | 2989 fps | 96.3% |
| IMR 4198 | <<locked>> | 86% | 57,058 psi | 89% | 2913 fps | 100% |
| IMR 4451 Enduronᴾ | <<locked>> | 100% | 56,130 psi | 88% | 3002 fps | 96% |
| IMR 4831ᴾ | <<locked>> | 100% | 43,888 psi | 69% | 2871 fps | 96.5% |
| IMR 4895 | <<locked>> | 94% | 54,911 psi | 86% | 3054 fps | 99.4% |
| IMR 8208 XBR | <<locked>> | 90% | 55,143 psi | 86% | 2992 fps | 99.8% |
| Lovex D073.5 | <<locked>> | 86% | 55,027 psi | 86% | 2972 fps | 100% |
| Lovex D073.6 | <<locked>> | 92% | 54,795 psi | 86% | 3009 fps | 100% |
| Lovex S060 | <<locked>> | 92% | 56,043 psi | 88% | 2963 fps | 99.4% |
| Lovex S062 | <<locked>> | 96% | 55,564 psi | 87% | 3005 fps | 99.9% |
| Lovex S065ᴾ | <<locked>> | 100% | 51,242 psi | 80% | 2933 fps | 96.6% |
| Norma 200 | <<locked>> | 82% | 56,115 psi | 88% | 2920 fps | 100% |
| Norma 201 | <<locked>> | 94% | 57,682 psi | 90% | 3028 fps | 100% |
| Norma 202 | <<locked>> | 92% | 54,868 psi | 86% | 2989 fps | 100% |
| Norma 203B | <<locked>> | 96% | 55,927 psi | 88% | 3058 fps | 99.5% |
| Norma URPᴾ | <<locked>> | 100% | 46,108 psi | 72% | 2930 fps | 96.8% |
| Ramshot Big Game | <<locked>> | 96% | 56,768 psi | 89% | 3084 fps | 99.4% |
| Ramshot TAC | <<locked>> | 90% | 55,985 psi | 88% | 3005 fps | 97.6% |
| Ramshot Wild Boar | <<locked>> | 90% | 54,824 psi | 86% | 3022 fps | 99.3% |
| Ramshot X-Terminator | <<locked>> | 88% | 56,550 psi | 89% | 2992 fps | 99.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 34,592 psi | 54% | 1864 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 86% | 54,781 psi | 86% | 2976 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 96% | 55,172 psi | 86% | 2995 fps | 96.6% |
| ReloadSwiss RS 52 | <<locked>> | 94% | 57,377 psi | 90% | 3143 fps | 99.3% |
| ReloadSwiss RS 60ᴾ | <<locked>> | 100% | 57,029 psi | 89% | 3179 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 45,774 psi | 72% | 2949 fps | 96.6% |
| Rottweil R 901 | <<locked>> | 90% | 55,027 psi | 86% | 2963 fps | 100% |
| Rottweil R 902 | <<locked>> | 94% | 54,781 psi | 86% | 2976 fps | 99.8% |
| Rottweil R 903ᴾ | <<locked>> | 100% | 56,217 psi | 88% | 3051 fps | 99.8% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 51,242 psi | 80% | 2933 fps | 96.6% |
| Shooters World Match Rifle | <<locked>> | 92% | 54,795 psi | 86% | 3009 fps | 100% |
| Shooters World Precision | <<locked>> | 96% | 55,564 psi | 87% | 3005 fps | 99.9% |
| Shooters World Tactical Rifle | <<locked>> | 84% | 54,824 psi | 86% | 2946 fps | 99.7% |
| SNPE Vectan BA6 1/2 | <<locked>> | 82% | 56,405 psi | 88% | 2631 fps | 100% |
| SNPE Vectan SP 10 | <<locked>> | 84% | 57,624 psi | 90% | 3025 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 98% | 54,679 psi | 86% | 3061 fps | 99.3% |
| SNPE Vectan SP 3 | <<locked>> | 84% | 54,041 psi | 85% | 2927 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 92% | 57,479 psi | 90% | 3028 fps | 98.3% |
| SNPE Vectan SP 9 | <<locked>> | 92% | 54,143 psi | 85% | 2999 fps | 99.2% |
| SNPE Vectan Tubal 3000 | <<locked>> | 92% | 56,652 psi | 89% | 2927 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 98% | 56,492 psi | 89% | 2920 fps | 100% |
| Somchem S321 | <<locked>> | 88% | 56,637 psi | 89% | 3031 fps | 100% |
| Somchem S335 | <<locked>> | 92% | 55,608 psi | 87% | 2923 fps | 100% |
| Somchem S341 | <<locked>> | 92% | 57,072 psi | 89% | 3025 fps | 99.5% |
| Somchem S355ᴾ | <<locked>> | 100% | 56,608 psi | 89% | 3048 fps | 99.7% |
| Somchem S365ᴾ | <<locked>> | 100% | 40,915 psi | 64% | 2871 fps | 98.8% |
| Vihtavuori N130 | <<locked>> | 88% | 56,478 psi | 89% | 2897 fps | 100% |
| Vihtavuori N133 | <<locked>> | 92% | 56,565 psi | 89% | 2913 fps | 100% |
| Vihtavuori N135 | <<locked>> | 96% | 57,217 psi | 90% | 2992 fps | 100% |
| Vihtavuori N140 | <<locked>> | 94% | 55,288 psi | 87% | 2963 fps | 100% |
| Vihtavuori N150ᴾ | <<locked>> | 100% | 55,085 psi | 86% | 2982 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 48,588 psi | 76% | 2930 fps | 97.3% |
| Vihtavuori N530 | <<locked>> | 90% | 55,869 psi | 88% | 2992 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 96% | 57,290 psi | 90% | 3012 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 47,659 psi | 75% | 2933 fps | 96.9% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 49,908 psi | 78% | 2923 fps | 99.2% |
| Winchester 748 | <<locked>> | 90% | 55,143 psi | 86% | 3041 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 92% | 53,838 psi | 84% | 3009 fps | 99.5% |
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% | 41,191 psi | 65% | 2697 fps | 100% |
| Accurate 2200 | <<locked>> | 80% | 53,243 psi | 83% | 2986 fps | 98.5% |
| Accurate 2460 | <<locked>> | 80% | 44,773 psi | 70% | 2799 fps | 99.9% |
| Accurate 2495 | <<locked>> | 80% | 33,170 psi | 52% | 2585 fps | 99.9% |
| Accurate 2520 | <<locked>> | 80% | 39,972 psi | 63% | 2743 fps | 99.2% |
| Accurate 4064 | <<locked>> | 80% | 31,430 psi | 49% | 2562 fps | 98.2% |
| Accurate 4350 | <<locked>> | 96% | 39,566 psi | 62% | 2805 fps | 95.2% |
| Accurate LT-30 | <<locked>> | 80% | 49,908 psi | 78% | 2795 fps | 100% |
| Accurate LT-32 | <<locked>> | 80% | 50,285 psi | 79% | 2815 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 37,956 psi | 59% | 2697 fps | 96% |
| ADI AR 2208 | <<locked>> | 86% | 39,044 psi | 61% | 2700 fps | 95.6% |
| ADI AR 2219 | <<locked>> | 80% | 50,053 psi | 78% | 2907 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 80% | 40,059 psi | 63% | 2717 fps | 97.9% |
| Alliant AR-Comp | <<locked>> | 80% | 38,928 psi | 61% | 2723 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 46,412 psi | 73% | 2927 fps | 98.7% |
| Alliant Power Pro 2000-MR | 53 gr | 84% | 39,320 psi | 62% | 2822 fps | 95.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 33,446 psi | 52% | 2608 fps | 95.6% |
| Alliant Reloder-10x | <<locked>> | 80% | 46,818 psi | 73% | 2808 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 38,508 psi | 60% | 2726 fps | 95.6% |
| Alliant Reloder-16 | <<locked>> | 96% | 40,611 psi | 64% | 2825 fps | 95.4% |
| Alliant Reloder-17 | <<locked>> | 88% | 35,491 psi | 56% | 2733 fps | 95.4% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 49,066 psi | 77% | 2785 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 39,465 psi | 62% | 2746 fps | 95.2% |
| Bofors RP3 | <<locked>> | 82% | 32,576 psi | 51% | 2602 fps | 95.4% |
| Hodgdon Benchmark | <<locked>> | 80% | 41,959 psi | 66% | 2713 fps | 98.8% |
| Hodgdon BL-C2 | <<locked>> | 80% | 38,130 psi | 60% | 2726 fps | 98% |
| Hodgdon CFE223 | <<locked>> | 80% | 41,872 psi | 66% | 2861 fps | 96.6% |
| Hodgdon H322 | <<locked>> | 80% | 45,672 psi | 72% | 2835 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 46,470 psi | 73% | 2854 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 41,466 psi | 65% | 2779 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 38,261 psi | 60% | 2710 fps | 96.8% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 34,505 psi | 54% | 2648 fps | 95.2% |
| Hodgdon LEVERevolution | 49.5 gr | 80% | 34,200 psi | 54% | 2661 fps | 95.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,570 psi | 40% | 1631 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 36,811 psi | 58% | 2657 fps | 96.2% |
| IMR 3031 | <<locked>> | 80% | 37,159 psi | 58% | 2720 fps | 99.9% |
| IMR 4064 | <<locked>> | 84% | 38,508 psi | 60% | 2684 fps | 95.7% |
| IMR 4166 Enduron | <<locked>> | 92% | 53,664 psi | 84% | 2933 fps | 95.5% |
| IMR 4198 | <<locked>> | 80% | 47,659 psi | 75% | 2779 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 98% | 52,663 psi | 83% | 2946 fps | 95.2% |
| IMR 4831 | <<locked>> | 98% | 40,959 psi | 64% | 2812 fps | 95.7% |
| IMR 4895 | <<locked>> | 80% | 34,650 psi | 54% | 2648 fps | 95% |
| IMR 8208 XBR | <<locked>> | 80% | 40,059 psi | 63% | 2717 fps | 97.9% |
| Lovex D073.5 | <<locked>> | 80% | 44,643 psi | 70% | 2802 fps | 99.4% |
| Lovex D073.6 | <<locked>> | 80% | 36,114 psi | 57% | 2671 fps | 98.5% |
| Lovex S060 | <<locked>> | 80% | 38,754 psi | 61% | 2644 fps | 96.3% |
| Lovex S062 | <<locked>> | 80% | 33,388 psi | 52% | 2575 fps | 96.1% |
| Lovex S065 | <<locked>> | 96% | 45,223 psi | 71% | 2825 fps | 95.1% |
| Norma 200 | <<locked>> | 80% | 52,547 psi | 82% | 2871 fps | 100% |
| Norma 201 | <<locked>> | 80% | 36,912 psi | 58% | 2648 fps | 97.2% |
| Norma 202 | <<locked>> | 80% | 37,173 psi | 58% | 2667 fps | 99.1% |
| Norma 203B | <<locked>> | 82% | 35,360 psi | 55% | 2657 fps | 95.2% |
| Norma URP | <<locked>> | 96% | 40,306 psi | 63% | 2812 fps | 95.2% |
| Ramshot Big Game | <<locked>> | 84% | 37,608 psi | 59% | 2730 fps | 95.7% |
| Ramshot TAC | <<locked>> | 84% | 45,643 psi | 72% | 2822 fps | 95.4% |
| Ramshot Wild Boar | <<locked>> | 80% | 38,972 psi | 61% | 2726 fps | 96.3% |
| Ramshot X-Terminator | <<locked>> | 80% | 43,497 psi | 68% | 2766 fps | 97.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,701 psi | 40% | 1670 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 45,005 psi | 71% | 2812 fps | 99.6% |
| ReloadSwiss RS 50 | <<locked>> | 92% | 48,501 psi | 76% | 2884 fps | 95.1% |
| ReloadSwiss RS 52 | 50.1 gr | 82% | 37,347 psi | 59% | 2769 fps | 95.1% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 30,821 psi | 48% | 2615 fps | 96% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 42,743 psi | 67% | 2887 fps | 95.7% |
| Rottweil R 901 | <<locked>> | 80% | 40,553 psi | 64% | 2710 fps | 99.5% |
| Rottweil R 902 | <<locked>> | 80% | 35,215 psi | 55% | 2602 fps | 96.6% |
| Rottweil R 903 | <<locked>> | 84% | 32,706 psi | 51% | 2595 fps | 95.1% |
| Shooters World Long Rifle | <<locked>> | 96% | 45,223 psi | 71% | 2825 fps | 95.1% |
| Shooters World Match Rifle | <<locked>> | 80% | 36,114 psi | 57% | 2671 fps | 98.5% |
| Shooters World Precision | <<locked>> | 80% | 33,388 psi | 52% | 2575 fps | 96.1% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 47,761 psi | 75% | 2831 fps | 99% |
| SNPE Vectan BA6 1/2 | <<locked>> | 80% | 53,751 psi | 84% | 2598 fps | 100% |
| SNPE Vectan SP 10 | <<locked>> | 80% | 50,415 psi | 79% | 2913 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 36,666 psi | 57% | 2713 fps | 95.4% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 47,688 psi | 75% | 2828 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 43,584 psi | 68% | 2792 fps | 95.5% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 36,506 psi | 57% | 2657 fps | 95.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 38,827 psi | 61% | 2625 fps | 99.3% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 31,807 psi | 50% | 2480 fps | 98.8% |
| Somchem S321 | <<locked>> | 80% | 42,989 psi | 67% | 2799 fps | 98.8% |
| Somchem S335 | <<locked>> | 80% | 38,145 psi | 60% | 2625 fps | 99.7% |
| Somchem S341 | <<locked>> | 80% | 37,608 psi | 59% | 2674 fps | 95.8% |
| Somchem S355 | <<locked>> | 84% | 33,982 psi | 53% | 2612 fps | 95.3% |
| Somchem S365 | <<locked>> | 92% | 31,488 psi | 49% | 2631 fps | 95.5% |
| Vihtavuori N130 | <<locked>> | 80% | 44,106 psi | 69% | 2710 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 39,001 psi | 61% | 2631 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 34,113 psi | 53% | 2598 fps | 99.9% |
| Vihtavuori N140 | <<locked>> | 80% | 35,230 psi | 55% | 2605 fps | 99% |
| Vihtavuori N150 | <<locked>> | 82% | 30,066 psi | 47% | 2490 fps | 95.3% |
| Vihtavuori N160 | <<locked>> | 96% | 42,467 psi | 67% | 2815 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 39,900 psi | 63% | 2710 fps | 98% |
| Vihtavuori N540 | <<locked>> | 80% | 33,779 psi | 53% | 2585 fps | 98.3% |
| Vihtavuori N550 | <<locked>> | 96% | 41,669 psi | 65% | 2818 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 35,505 psi | 56% | 2628 fps | 95.6% |
| Winchester 748 | <<locked>> | 80% | 38,899 psi | 61% | 2749 fps | 98.5% |
| Winchester StaBALL Match | <<locked>> | 80% | 35,563 psi | 56% | 2657 fps | 96% |
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 95 powders for .300 RCM loaded with the .308 | 146gr | Peregrine Glider (Glider GRM). ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,179 fps; across all powders the maximum-charge window runs from 1,824 fps to 3,179 fps. Accurate 4350 gives the best case fill at 100 %, and 95 of the 95 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 54–90 %, leaving at least 10 % headroom. The 146.0 gr projectile in 0.308" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 4350, Alliant Reloder-16, Alliant Reloder-17 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, ReloadSwiss RS 52, Hodgdon LEVERevolution rank at the top here: for .300 RCM with the .308 | 146gr | Peregrine Glider (Glider GRM) 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.