Load Specifications
Load data in caliber 37XC with .374 | 300gr | Rhino Solid Shank bullet and 96 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N560, Accurate MAGPRO and Norma MRP.
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: 30"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2700 | <<locked>> | 82% | 59,901 psi | 86% | 2808 fps | 100% |
| Accurate 3100 | <<locked>> | 98% | 60,263 psi | 87% | 2877 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 59,988 psi | 86% | 2769 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 62,047 psi | 89% | 2910 fps | 100% |
| Accurate MAGPRO | <<locked>> | 96% | 58,813 psi | 84% | 2999 fps | 99.5% |
| ADI APS 450 | <<locked>> | 84% | 62,946 psi | 90% | 2198 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 62,729 psi | 90% | 2854 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 62,671 psi | 90% | 2976 fps | 100% |
| ADI AR 2213 | <<locked>> | 98% | 60,307 psi | 87% | 2989 fps | 99.9% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 47,050 psi | 68% | 2779 fps | 99% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,843 psi | 60% | 2753 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 60,568 psi | 87% | 2831 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 60,611 psi | 87% | 2858 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 62,555 psi | 90% | 2956 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 60,220 psi | 87% | 2927 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 61,946 psi | 89% | 2963 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 98% | 60,017 psi | 86% | 2982 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 61,003 psi | 88% | 2930 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 52,736 psi | 76% | 2904 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 62,352 psi | 90% | 3041 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 61,975 psi | 89% | 2949 fps | 98.7% |
| Bofors RP15ᴾ | <<locked>> | 100% | 58,726 psi | 84% | 2966 fps | 100% |
| Bofors RP3 | <<locked>> | 84% | 61,859 psi | 89% | 2848 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 48,733 psi | 70% | 2854 fps | 99.4% |
| Bofors RP5 | <<locked>> | 98% | 60,017 psi | 86% | 2982 fps | 100% |
| Bofors RP7 | <<locked>> | 88% | 60,597 psi | 87% | 2861 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 51,866 psi | 75% | 2861 fps | 99.8% |
| Hodgdon H380 | <<locked>> | 84% | 61,859 psi | 89% | 2877 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 59,727 psi | 86% | 2917 fps | 100% |
| Hodgdon H4350 | <<locked>> | 88% | 62,584 psi | 90% | 2923 fps | 100% |
| Hodgdon H4831 | <<locked>> | 96% | 60,191 psi | 86% | 2927 fps | 99.7% |
| Hodgdon H4831 SC | <<locked>> | 96% | 58,987 psi | 85% | 2907 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 62,830 psi | 90% | 2867 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 51,648 psi | 74% | 2976 fps | 100% |
| Hodgdon Superformance | <<locked>> | 88% | 60,611 psi | 87% | 2963 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,985 psi | 53% | 1739 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 62,337 psi | 90% | 2838 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 60,887 psi | 87% | 2838 fps | 100% |
| IMR 4350 | <<locked>> | 92% | 62,134 psi | 89% | 2897 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 88% | 62,004 psi | 89% | 2881 fps | 100% |
| IMR 4831 | <<locked>> | 92% | 61,931 psi | 89% | 2894 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 62,236 psi | 89% | 2881 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 61,134 psi | 88% | 2904 fps | 99.7% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 61,946 psi | 89% | 3022 fps | 100% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 37,478 psi | 54% | 2661 fps | 97.1% |
| Lovex S062 | <<locked>> | 84% | 62,743 psi | 90% | 2825 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 62,555 psi | 90% | 2871 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 60,597 psi | 87% | 2874 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,766 psi | 77% | 2795 fps | 100% |
| Norma 203B | <<locked>> | 82% | 59,944 psi | 86% | 2841 fps | 100% |
| Norma 204 | <<locked>> | 90% | 59,654 psi | 86% | 2910 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 37,347 psi | 54% | 2684 fps | 99% |
| Norma MRP | <<locked>> | 96% | 59,973 psi | 86% | 3005 fps | 100% |
| Norma URP | <<locked>> | 90% | 60,017 psi | 86% | 2890 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 61,119 psi | 88% | 2871 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 58,755 psi | 84% | 2986 fps | 100% |
| Ramshot Hunter | <<locked>> | 92% | 62,859 psi | 90% | 2956 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 56,884 psi | 82% | 2920 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,753 psi | 54% | 1781 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 61,583 psi | 88% | 2867 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 59,857 psi | 86% | 2910 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 61,989 psi | 89% | 2933 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 60,307 psi | 87% | 2969 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 52,185 psi | 75% | 2972 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 47,123 psi | 68% | 2867 fps | 98.3% |
| Rottweil R 902 | <<locked>> | 82% | 60,814 psi | 87% | 2785 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 62,047 psi | 89% | 2848 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 60,002 psi | 86% | 2890 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 96% | 61,540 psi | 88% | 2953 fps | 100% |
| Rottweil R 907 | <<locked>> | 88% | 60,597 psi | 87% | 2861 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 90% | 62,555 psi | 90% | 2871 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 62,743 psi | 90% | 2825 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 60,597 psi | 87% | 2874 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 59,872 psi | 86% | 2861 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 61,699 psi | 89% | 2703 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 62,163 psi | 89% | 2831 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 61,061 psi | 88% | 2949 fps | 100% |
| Somchem S355 | <<locked>> | 86% | 61,583 psi | 88% | 2841 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 61,917 psi | 89% | 2884 fps | 99.7% |
| Somchem S365 | <<locked>> | 92% | 60,481 psi | 87% | 2887 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 61,931 psi | 89% | 2917 fps | 100% |
| Vihtavuori N135 | <<locked>> | 82% | 61,598 psi | 88% | 2730 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 61,569 psi | 88% | 2753 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 59,146 psi | 85% | 2762 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 62,105 psi | 89% | 2877 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 61,409 psi | 88% | 2897 fps | 100% |
| Vihtavuori N540 | <<locked>> | 82% | 59,698 psi | 86% | 2756 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 61,148 psi | 88% | 2890 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 59,683 psi | 86% | 2910 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 59,785 psi | 86% | 3009 fps | 99.8% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 55,347 psi | 80% | 2927 fps | 99.6% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 48,428 psi | 70% | 2871 fps | 98% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 61,801 psi | 89% | 2835 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 59,872 psi | 86% | 2920 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 58,639 psi | 84% | 3025 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 62,381 psi | 90% | 2920 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 30"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2700 | <<locked>> | 80% | 56,014 psi | 80% | 2759 fps | 100% |
| Accurate 3100 | <<locked>> | 80% | 32,953 psi | 47% | 2431 fps | 98.6% |
| Accurate 4064 | <<locked>> | 80% | 56,333 psi | 81% | 2726 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 44,295 psi | 64% | 2661 fps | 100% |
| Accurate MAGPRO | 99.4 gr | 84% | 38,522 psi | 55% | 2648 fps | 95.7% |
| ADI APS 450 | <<locked>> | 80% | 58,929 psi | 85% | 2146 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 52,228 psi | 75% | 2720 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,985 psi | 53% | 2549 fps | 97.4% |
| ADI AR 2213 | <<locked>> | 82% | 35,273 psi | 51% | 2539 fps | 95.5% |
| ADI AR 2217 | <<locked>> | 90% | 33,939 psi | 49% | 2500 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 86% | 26,905 psi | 39% | 2362 fps | 95.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 53,432 psi | 77% | 2740 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 56,971 psi | 82% | 2812 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 42,366 psi | 61% | 2667 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,820 psi | 70% | 2776 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,999 psi | 53% | 2549 fps | 97.5% |
| Alliant Reloder-22 | <<locked>> | 80% | 32,764 psi | 47% | 2493 fps | 96.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,575 psi | 45% | 2457 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,630 psi | 40% | 2379 fps | 97.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 34,229 psi | 49% | 2592 fps | 99.8% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 45,484 psi | 65% | 2680 fps | 95.4% |
| Bofors RP15 | <<locked>> | 80% | 30,603 psi | 44% | 2434 fps | 95.2% |
| Bofors RP3 | <<locked>> | 80% | 54,331 psi | 78% | 2756 fps | 100% |
| Bofors RP30 | <<locked>> | 88% | 32,648 psi | 47% | 2523 fps | 95.5% |
| Bofors RP5 | <<locked>> | 80% | 32,764 psi | 47% | 2493 fps | 96.3% |
| Bofors RP7 | <<locked>> | 80% | 47,152 psi | 68% | 2661 fps | 99.7% |
| Hodgdon H1000 | <<locked>> | 86% | 32,445 psi | 47% | 2467 fps | 95.2% |
| Hodgdon H380 | <<locked>> | 80% | 54,360 psi | 78% | 2779 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 45,934 psi | 66% | 2710 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 80% | 48,486 psi | 70% | 2720 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 82% | 37,608 psi | 54% | 2543 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 82% | 36,956 psi | 53% | 2530 fps | 95.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 40,074 psi | 58% | 2552 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 84% | 30,632 psi | 44% | 2507 fps | 95.9% |
| Hodgdon Superformance | <<locked>> | 80% | 45,150 psi | 65% | 2736 fps | 99.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,702 psi | 40% | 1555 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 54,984 psi | 79% | 2746 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 57,116 psi | 82% | 2789 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,699 psi | 61% | 2602 fps | 99.3% |
| IMR 4451 Enduron | <<locked>> | 80% | 48,544 psi | 70% | 2684 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 42,192 psi | 61% | 2608 fps | 100% |
| IMR 4895 | <<locked>> | 80% | 58,465 psi | 84% | 2835 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 37,072 psi | 53% | 2493 fps | 95.6% |
| IMR 7828 SSC | <<locked>> | 82% | 33,866 psi | 49% | 2516 fps | 95% |
| IMR 8133 Enduron | <<locked>> | 96% | 32,909 psi | 47% | 2549 fps | 95.3% |
| Lovex S062 | <<locked>> | 80% | 55,434 psi | 80% | 2733 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 46,093 psi | 66% | 2635 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 44,440 psi | 64% | 2631 fps | 99.8% |
| Lovex S071 | <<locked>> | 80% | 28,369 psi | 41% | 2313 fps | 97.2% |
| Norma 203B | <<locked>> | 80% | 56,318 psi | 81% | 2795 fps | 100% |
| Norma 204 | <<locked>> | 80% | 42,569 psi | 61% | 2641 fps | 98.6% |
| Norma 217 | <<locked>> | 92% | 28,921 psi | 42% | 2464 fps | 96% |
| Norma MRP | 92.9 gr | 80% | 34,200 psi | 49% | 2559 fps | 98.2% |
| Norma URP | <<locked>> | 80% | 43,511 psi | 63% | 2648 fps | 100% |
| Ramshot Big Game | <<locked>> | 80% | 57,305 psi | 82% | 2822 fps | 100% |
| Ramshot Grand | <<locked>> | 82% | 33,286 psi | 48% | 2516 fps | 95.2% |
| Ramshot Hunter | <<locked>> | 80% | 42,337 psi | 61% | 2651 fps | 99.9% |
| Ramshot Magnum | <<locked>> | 82% | 29,530 psi | 42% | 2405 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,326 psi | 41% | 1594 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 54,012 psi | 78% | 2766 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,793 psi | 74% | 2808 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 44,048 psi | 63% | 2680 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 42,351 psi | 61% | 2703 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 82% | 27,688 psi | 40% | 2418 fps | 95.5% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 37,724 psi | 54% | 2680 fps | 95.7% |
| Rottweil R 902 | <<locked>> | 80% | 57,334 psi | 82% | 2743 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 51,256 psi | 74% | 2707 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 38,377 psi | 55% | 2526 fps | 96.7% |
| Rottweil R 905 | <<locked>> | 80% | 36,260 psi | 52% | 2533 fps | 97.5% |
| Rottweil R 907 | <<locked>> | 80% | 47,152 psi | 68% | 2661 fps | 99.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 46,093 psi | 66% | 2635 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 55,434 psi | 80% | 2733 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 44,440 psi | 64% | 2631 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 52,547 psi | 75% | 2766 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 51,445 psi | 74% | 2582 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 45,020 psi | 65% | 2585 fps | 99.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,926 psi | 52% | 2526 fps | 97.3% |
| Somchem S355 | <<locked>> | 80% | 51,039 psi | 73% | 2703 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 39,015 psi | 56% | 2516 fps | 96% |
| Somchem S365 | <<locked>> | 80% | 40,393 psi | 58% | 2605 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,825 psi | 53% | 2513 fps | 98.3% |
| Vihtavuori N135 | <<locked>> | 80% | 57,943 psi | 83% | 2690 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 57,885 psi | 83% | 2710 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 48,892 psi | 70% | 2628 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,962 psi | 65% | 2641 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 31,879 psi | 46% | 2395 fps | 96.4% |
| Vihtavuori N540 | <<locked>> | 80% | 56,043 psi | 81% | 2713 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 44,280 psi | 64% | 2648 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 35,404 psi | 51% | 2526 fps | 100% |
| Vihtavuori N560 | 95.3 gr | 82% | 37,043 psi | 53% | 2608 fps | 95.8% |
| Vihtavuori N565 | <<locked>> | 86% | 34,389 psi | 49% | 2539 fps | 95.3% |
| Vihtavuori N568 | <<locked>> | 94% | 39,320 psi | 56% | 2694 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,801 psi | 63% | 2598 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 46,050 psi | 66% | 2713 fps | 99.9% |
| Winchester StaBALL HD | <<locked>> | 80% | 28,036 psi | 40% | 2487 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 33,547 psi | 48% | 2441 fps | 96.4% |
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 101 powders for 37XC loaded with the .374 | 300gr | Rhino Solid Shank. Alliant Reloder-26 delivers the highest muzzle velocity at 3,041 fps; across all powders the maximum-charge window runs from 1,739 fps to 3,041 fps. ADI AR 2217 gives the best case fill at 100 %, and 101 of the 101 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (480 MPa), the top charges use 53–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.374" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2218, ADI AR 2225 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. Vihtavuori N560, Accurate MAGPRO, Norma MRP rank at the top here: for 37XC with the .374 | 300gr | Rhino Solid Shank they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2218, Alliant Reloder-33, IMR 7977 Enduron 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.