Load Specifications
Load data in caliber .300 Win. Mag. with .309 | 170gr | Reichenberg HDB Universal 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, Alliant Reloder-16 and Alliant Reloder-26.
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 2495 | <<locked>> | 84% | 55,666 psi | 89% | 2822 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 54,288 psi | 87% | 2844 fps | 98.3% |
| Accurate 3100ᴾ | <<locked>> | 100% | 51,053 psi | 82% | 2874 fps | 99.1% |
| Accurate 4064 | <<locked>> | 86% | 56,246 psi | 90% | 2877 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 53,563 psi | 86% | 2933 fps | 100% |
| ADI AR 2206H | <<locked>> | 82% | 55,680 psi | 89% | 2910 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 53,563 psi | 86% | 2867 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 54,984 psi | 88% | 2979 fps | 97.8% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 52,431 psi | 84% | 2963 fps | 95.9% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 56,362 psi | 90% | 3045 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 54,056 psi | 87% | 2887 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 54,389 psi | 87% | 2910 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 54,520 psi | 87% | 2995 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 90% | 55,840 psi | 90% | 3018 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 54,215 psi | 87% | 2963 fps | 97.7% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 51,053 psi | 82% | 2956 fps | 97.3% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 48,327 psi | 77% | 2900 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 42,061 psi | 67% | 2812 fps | 98.3% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 55,651 psi | 89% | 3097 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 55,811 psi | 89% | 2933 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 46,949 psi | 75% | 2881 fps | 96.2% |
| Bofors RP3 | <<locked>> | 86% | 54,621 psi | 88% | 2900 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 51,053 psi | 82% | 2956 fps | 97.3% |
| Bofors RP7 | <<locked>> | 90% | 54,447 psi | 87% | 2887 fps | 98.5% |
| Hodgdon H380 | <<locked>> | 86% | 55,259 psi | 89% | 2920 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 92% | 55,970 psi | 90% | 2989 fps | 99.2% |
| Hodgdon H4350 | <<locked>> | 90% | 55,956 psi | 90% | 2949 fps | 98.2% |
| Hodgdon H4831ᴾ | <<locked>> | 100% | 56,391 psi | 90% | 2969 fps | 96.1% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 55,114 psi | 88% | 2949 fps | 95.9% |
| Hodgdon H4895 | <<locked>> | 82% | 56,304 psi | 90% | 2920 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 54,766 psi | 88% | 2917 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 53,011 psi | 85% | 2904 fps | 100% |
| Hodgdon Superformance | <<locked>> | 90% | 52,446 psi | 84% | 2963 fps | 98.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,158 psi | 58% | 1811 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 53,925 psi | 86% | 2871 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 56,420 psi | 90% | 2900 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 55,738 psi | 89% | 2884 fps | 99% |
| IMR 4350 | <<locked>> | 94% | 55,477 psi | 89% | 2920 fps | 98.7% |
| IMR 4451 Enduron | <<locked>> | 90% | 56,202 psi | 90% | 2917 fps | 99% |
| IMR 4831 | <<locked>> | 94% | 54,099 psi | 87% | 2927 fps | 100% |
| IMR 4895 | <<locked>> | 84% | 55,825 psi | 90% | 2940 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 54,505 psi | 87% | 2904 fps | 96% |
| Lovex D073.6 | <<locked>> | 82% | 55,869 psi | 90% | 2881 fps | 100% |
| Lovex S060 | <<locked>> | 82% | 54,723 psi | 88% | 2838 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 56,333 psi | 90% | 2890 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 55,999 psi | 90% | 2910 fps | 99.7% |
| Lovex S070 | <<locked>> | 92% | 53,708 psi | 86% | 2897 fps | 99% |
| Lovex S071ᴾ | <<locked>> | 100% | 42,351 psi | 68% | 2717 fps | 97.6% |
| Norma 201 | <<locked>> | 82% | 54,288 psi | 87% | 2854 fps | 100% |
| Norma 202 | <<locked>> | 82% | 55,027 psi | 88% | 2851 fps | 100% |
| Norma 203B | <<locked>> | 84% | 53,679 psi | 86% | 2897 fps | 100% |
| Norma 204 | <<locked>> | 94% | 56,231 psi | 90% | 2972 fps | 97.8% |
| Norma MRPᴾ | <<locked>> | 100% | 54,273 psi | 87% | 3045 fps | 99% |
| Norma URP | <<locked>> | 94% | 56,130 psi | 90% | 2976 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 54,389 psi | 87% | 2923 fps | 100% |
| Ramshot Hunter | <<locked>> | 94% | 54,955 psi | 88% | 2976 fps | 99.5% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 44,411 psi | 71% | 2812 fps | 96.3% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,796 psi | 59% | 1854 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 55,390 psi | 89% | 2907 fps | 99.4% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 55,347 psi | 89% | 2979 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 55,477 psi | 89% | 3012 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 53,476 psi | 86% | 2956 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 55,941 psi | 90% | 3041 fps | 100% |
| Rottweil R 902 | <<locked>> | 84% | 55,013 psi | 88% | 2854 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 54,723 psi | 88% | 2897 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 53,113 psi | 85% | 2890 fps | 96.3% |
| Rottweil R 905 | <<locked>> | 98% | 53,171 psi | 85% | 2946 fps | 97.7% |
| Rottweil R 907 | <<locked>> | 90% | 54,447 psi | 87% | 2887 fps | 98.5% |
| Shooters World Long Rifle | <<locked>> | 92% | 55,999 psi | 90% | 2910 fps | 99.7% |
| Shooters World Match Rifle | <<locked>> | 82% | 55,869 psi | 90% | 2881 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 56,333 psi | 90% | 2890 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 53,708 psi | 86% | 2897 fps | 99% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 52,997 psi | 85% | 2907 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 54,273 psi | 87% | 2884 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 55,230 psi | 89% | 2785 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 56,217 psi | 90% | 2789 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 55,869 psi | 90% | 2864 fps | 99.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 52,692 psi | 84% | 2943 fps | 97.6% |
| Somchem S335 | <<locked>> | 82% | 54,911 psi | 88% | 2782 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 54,824 psi | 88% | 2894 fps | 100% |
| Somchem S365 | <<locked>> | 96% | 55,114 psi | 88% | 2972 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 53,911 psi | 86% | 2927 fps | 98.5% |
| Vihtavuori N133 | <<locked>> | 82% | 55,782 psi | 89% | 2769 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 55,230 psi | 89% | 2815 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 55,724 psi | 89% | 2831 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 56,362 psi | 90% | 2871 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 54,766 psi | 88% | 2917 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 49,545 psi | 79% | 2838 fps | 97.3% |
| Vihtavuori N540 | <<locked>> | 84% | 53,824 psi | 86% | 2825 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 53,664 psi | 86% | 2920 fps | 99.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 53,896 psi | 86% | 2976 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 54,723 psi | 88% | 3031 fps | 96.2% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 54,433 psi | 87% | 2884 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 56,217 psi | 90% | 2992 fps | 99.2% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 43,265 psi | 69% | 2943 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 54,331 psi | 87% | 2890 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 54,085 psi | 87% | 2917 fps | 97.6% |
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 2495 | <<locked>> | 80% | 48,936 psi | 78% | 2726 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 47,413 psi | 76% | 2730 fps | 97% |
| Accurate 3100 | <<locked>> | 90% | 36,027 psi | 58% | 2585 fps | 95.7% |
| Accurate 4064 | <<locked>> | 80% | 46,412 psi | 74% | 2730 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 34,925 psi | 56% | 2575 fps | 97.1% |
| ADI AR 2206H | <<locked>> | 80% | 52,156 psi | 84% | 2858 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 44,338 psi | 71% | 2707 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 92% | 45,005 psi | 72% | 2795 fps | 95.4% |
| ADI AR 2213 | <<locked>> | 98% | 49,197 psi | 79% | 2900 fps | 95% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 48,907 psi | 78% | 2920 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 44,643 psi | 72% | 2733 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 47,659 psi | 76% | 2799 fps | 99.8% |
| Alliant Reloder-16 | 57.3 gr | 80% | 34,592 psi | 55% | 2592 fps | 97.3% |
| Alliant Reloder-17 | <<locked>> | 80% | 39,102 psi | 63% | 2720 fps | 99.6% |
| Alliant Reloder-19 | <<locked>> | 92% | 44,541 psi | 71% | 2789 fps | 95.5% |
| Alliant Reloder-22 | <<locked>> | 96% | 44,701 psi | 72% | 2838 fps | 95.7% |
| Alliant Reloder-23 | <<locked>> | 82% | 26,687 psi | 43% | 2388 fps | 95.2% |
| Alliant Reloder-25 | <<locked>> | 94% | 34,621 psi | 56% | 2628 fps | 95.6% |
| Alliant Reloder-26 | 68 gr | 86% | 32,909 psi | 53% | 2625 fps | 95.8% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 52,054 psi | 83% | 2874 fps | 99.9% |
| Bofors RP15 | <<locked>> | 98% | 43,859 psi | 70% | 2818 fps | 95.3% |
| Bofors RP3 | <<locked>> | 80% | 44,686 psi | 72% | 2740 fps | 100% |
| Bofors RP5 | <<locked>> | 96% | 44,701 psi | 72% | 2838 fps | 95.7% |
| Bofors RP7 | <<locked>> | 80% | 39,595 psi | 63% | 2605 fps | 95.1% |
| Hodgdon H380 | <<locked>> | 80% | 45,179 psi | 72% | 2746 fps | 99% |
| Hodgdon H414 | <<locked>> | 82% | 39,958 psi | 64% | 2690 fps | 95.9% |
| Hodgdon H4350 | <<locked>> | 82% | 43,178 psi | 69% | 2717 fps | 95.4% |
| Hodgdon H4831 | <<locked>> | 98% | 52,634 psi | 84% | 2907 fps | 95.3% |
| Hodgdon H4831 SC | <<locked>> | 98% | 51,677 psi | 83% | 2894 fps | 95.1% |
| Hodgdon H4895 | <<locked>> | 80% | 52,765 psi | 85% | 2867 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 31,981 psi | 51% | 2484 fps | 97.9% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 49,559 psi | 79% | 2851 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 39,073 psi | 63% | 2700 fps | 95.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,876 psi | 43% | 1617 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 50,488 psi | 81% | 2815 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 46,615 psi | 75% | 2743 fps | 99.8% |
| IMR 4166 Enduron | <<locked>> | 80% | 48,965 psi | 79% | 2769 fps | 98.1% |
| IMR 4350 | <<locked>> | 84% | 40,118 psi | 64% | 2638 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 80% | 40,988 psi | 66% | 2638 fps | 96% |
| IMR 4831 | <<locked>> | 80% | 33,895 psi | 54% | 2536 fps | 96.8% |
| IMR 4895 | <<locked>> | 80% | 48,907 psi | 78% | 2828 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 51,068 psi | 82% | 2848 fps | 95.2% |
| Lovex D073.6 | <<locked>> | 80% | 52,228 psi | 84% | 2831 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 51,314 psi | 82% | 2785 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 46,615 psi | 75% | 2736 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 38,464 psi | 62% | 2589 fps | 96.8% |
| Lovex S070 | <<locked>> | 82% | 39,131 psi | 63% | 2618 fps | 95.8% |
| Lovex S071 | <<locked>> | 94% | 34,664 psi | 56% | 2552 fps | 95.2% |
| Norma 201 | <<locked>> | 80% | 51,024 psi | 82% | 2802 fps | 100% |
| Norma 202 | <<locked>> | 80% | 51,706 psi | 83% | 2802 fps | 100% |
| Norma 203B | <<locked>> | 80% | 46,992 psi | 75% | 2782 fps | 99.9% |
| Norma 204 | <<locked>> | 88% | 45,629 psi | 73% | 2789 fps | 95.5% |
| Norma MRP | <<locked>> | 90% | 38,218 psi | 61% | 2726 fps | 95% |
| Norma URP | <<locked>> | 80% | 35,128 psi | 56% | 2575 fps | 97% |
| Ramshot Big Game | <<locked>> | 80% | 47,413 psi | 76% | 2808 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 82% | 36,535 psi | 59% | 2621 fps | 95.7% |
| Ramshot Magnum | <<locked>> | 98% | 41,336 psi | 66% | 2746 fps | 95.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,340 psi | 44% | 1657 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 45,368 psi | 73% | 2730 fps | 97.9% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 51,677 psi | 83% | 2920 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 41,640 psi | 67% | 2782 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 34,925 psi | 56% | 2595 fps | 96.7% |
| ReloadSwiss RS 70 | 62.7 gr | 80% | 34,171 psi | 55% | 2598 fps | 95.8% |
| Rottweil R 902 | <<locked>> | 80% | 48,414 psi | 78% | 2749 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 41,974 psi | 67% | 2684 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 94% | 49,879 psi | 80% | 2835 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 92% | 43,526 psi | 70% | 2772 fps | 95.4% |
| Rottweil R 907 | <<locked>> | 80% | 39,595 psi | 63% | 2605 fps | 95.1% |
| Shooters World Long Rifle | <<locked>> | 80% | 38,464 psi | 62% | 2589 fps | 96.8% |
| Shooters World Match Rifle | <<locked>> | 80% | 52,228 psi | 84% | 2831 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 46,615 psi | 75% | 2736 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 39,131 psi | 63% | 2618 fps | 95.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 43,381 psi | 70% | 2740 fps | 99.6% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 50,850 psi | 82% | 2828 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 51,866 psi | 83% | 2736 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 43,671 psi | 70% | 2602 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 37,623 psi | 60% | 2530 fps | 95.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 43,120 psi | 69% | 2766 fps | 95.2% |
| Somchem S335 | <<locked>> | 80% | 51,706 psi | 83% | 2736 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 42,540 psi | 68% | 2684 fps | 99.8% |
| Somchem S365 | <<locked>> | 80% | 31,517 psi | 51% | 2530 fps | 98.9% |
| Somchem S385 | <<locked>> | 90% | 41,162 psi | 66% | 2694 fps | 95.6% |
| Vihtavuori N133 | <<locked>> | 80% | 52,446 psi | 84% | 2723 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 48,588 psi | 78% | 2720 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 49,023 psi | 79% | 2733 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 40,567 psi | 65% | 2615 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 36,477 psi | 58% | 2579 fps | 97.4% |
| Vihtavuori N165 | <<locked>> | 96% | 43,366 psi | 70% | 2726 fps | 95.8% |
| Vihtavuori N540 | <<locked>> | 80% | 47,253 psi | 76% | 2726 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 35,940 psi | 58% | 2575 fps | 97% |
| Vihtavuori N555 | <<locked>> | 82% | 29,167 psi | 47% | 2461 fps | 95.4% |
| Vihtavuori N560 | <<locked>> | 98% | 51,169 psi | 82% | 2969 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 35,824 psi | 57% | 2552 fps | 99.1% |
| Winchester 760 | <<locked>> | 82% | 39,958 psi | 64% | 2690 fps | 95.9% |
| Winchester StaBALL HD | <<locked>> | 86% | 26,789 psi | 43% | 2470 fps | 96% |
| Winchester StaBALL Match | <<locked>> | 80% | 50,633 psi | 81% | 2831 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 43,685 psi | 70% | 2736 fps | 95.1% |
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 .300 Win. Mag. loaded with the .309 | 170gr | Reichenberg HDB Universal. Alliant Reloder-26 delivers the highest muzzle velocity at 3,097 fps; across all powders the maximum-charge window runs from 1,811 fps to 3,097 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 (430 MPa), the top charges use 58–90 %, leaving at least 10 % headroom. The 170.0 gr projectile in 0.309" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2213, Alliant Reloder-22 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, Alliant Reloder-16, Alliant Reloder-26 rank at the top here: for .300 Win. Mag. with the .309 | 170gr | Reichenberg HDB Universal 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.