Load Specifications
Load data in caliber .375 Blaser Mag. with .375 | 270gr | Speer Boat-Tail 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 Reloder-17, ReloadSwiss RS 60 and ReloadSwiss RS 70.
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: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 82% | 51,924 psi | 85% | 2575 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 53,911 psi | 89% | 2644 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 53,882 psi | 88% | 2694 fps | 100% |
| Accurate 2700 | <<locked>> | 92% | 54,099 psi | 89% | 2654 fps | 97.4% |
| Accurate 3100ᴾ | <<locked>> | 100% | 40,785 psi | 67% | 2549 fps | 96.5% |
| Accurate 4064 | <<locked>> | 90% | 53,751 psi | 88% | 2690 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 53,403 psi | 88% | 2776 fps | 99.8% |
| ADI AR 2206H | <<locked>> | 86% | 54,302 psi | 89% | 2720 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 52,083 psi | 86% | 2674 fps | 99.8% |
| ADI Benchmark 8208 | <<locked>> | 84% | 53,345 psi | 88% | 2674 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 54,041 psi | 89% | 2644 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 53,693 psi | 88% | 2835 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 52,025 psi | 85% | 2697 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 52,417 psi | 86% | 2713 fps | 99.9% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 54,549 psi | 90% | 2825 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 94% | 52,330 psi | 86% | 2812 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 39,059 psi | 64% | 2579 fps | 99.2% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 43,540 psi | 71% | 2733 fps | 98.6% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 53,940 psi | 89% | 2736 fps | 99.8% |
| Bofors RP3 | <<locked>> | 90% | 52,402 psi | 86% | 2710 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 52,663 psi | 86% | 2684 fps | 97.4% |
| Hodgdon Benchmark | <<locked>> | 84% | 55,056 psi | 90% | 2654 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 52,547 psi | 86% | 2703 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 54,404 psi | 89% | 2795 fps | 100% |
| Hodgdon H322 | <<locked>> | 82% | 53,272 psi | 87% | 2654 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 53,287 psi | 87% | 2720 fps | 99.5% |
| Hodgdon H414 | <<locked>> | 94% | 54,302 psi | 89% | 2795 fps | 98.4% |
| Hodgdon H4350 | <<locked>> | 98% | 54,882 psi | 90% | 2753 fps | 97.2% |
| Hodgdon H4895 | <<locked>> | 86% | 54,824 psi | 90% | 2730 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 50,937 psi | 84% | 2707 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 90% | 54,230 psi | 89% | 2766 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 53,243 psi | 87% | 2805 fps | 97.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,476 psi | 58% | 1644 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 54,882 psi | 90% | 2717 fps | 100% |
| IMR 3031 | <<locked>> | 88% | 53,316 psi | 88% | 2690 fps | 100% |
| IMR 4064 | <<locked>> | 92% | 54,070 psi | 89% | 2694 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 92% | 53,505 psi | 88% | 2667 fps | 98.1% |
| IMR 4350 | <<locked>> | 98% | 52,692 psi | 87% | 2703 fps | 97.5% |
| IMR 4451 Enduron | <<locked>> | 94% | 54,476 psi | 89% | 2710 fps | 98.1% |
| IMR 4831ᴾ | <<locked>> | 100% | 48,051 psi | 79% | 2677 fps | 99.4% |
| IMR 4895 | <<locked>> | 88% | 53,751 psi | 88% | 2743 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 53,345 psi | 88% | 2674 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 53,882 psi | 88% | 2694 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 53,867 psi | 88% | 2651 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 54,520 psi | 90% | 2700 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 53,809 psi | 88% | 2707 fps | 99.1% |
| Lovex S070 | <<locked>> | 98% | 54,723 psi | 90% | 2740 fps | 98.5% |
| Norma 201 | <<locked>> | 86% | 53,127 psi | 87% | 2667 fps | 100% |
| Norma 202 | <<locked>> | 86% | 53,592 psi | 88% | 2667 fps | 100% |
| Norma 203B | <<locked>> | 90% | 55,013 psi | 90% | 2749 fps | 100% |
| Norma 204 | <<locked>> | 98% | 53,171 psi | 87% | 2753 fps | 96.3% |
| Norma MRPᴾ | <<locked>> | 100% | 43,598 psi | 72% | 2690 fps | 95.9% |
| Norma URP | <<locked>> | 98% | 52,576 psi | 86% | 2762 fps | 99.7% |
| Ramshot Big Game | <<locked>> | 88% | 51,924 psi | 85% | 2726 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 54,810 psi | 90% | 2812 fps | 99% |
| Ramshot TAC | <<locked>> | 84% | 53,417 psi | 88% | 2694 fps | 99.1% |
| Ramshot Wild Boar | <<locked>> | 84% | 53,069 psi | 87% | 2707 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 54,070 psi | 89% | 2674 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,056 psi | 59% | 1683 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 53,563 psi | 88% | 2703 fps | 98.6% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 52,663 psi | 86% | 2776 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 52,112 psi | 86% | 2808 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 52,997 psi | 87% | 2795 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 52,591 psi | 86% | 2818 fps | 99.5% |
| Rottweil R 901 | <<locked>> | 84% | 54,201 psi | 89% | 2648 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 53,577 psi | 88% | 2667 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 52,257 psi | 86% | 2700 fps | 100% |
| Rottweil R 907 | <<locked>> | 94% | 52,663 psi | 86% | 2684 fps | 97.4% |
| Shooters World Long Rifle | <<locked>> | 96% | 53,809 psi | 88% | 2707 fps | 99.1% |
| Shooters World Match Rifle | <<locked>> | 86% | 53,882 psi | 88% | 2694 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 54,520 psi | 90% | 2700 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 54,723 psi | 90% | 2740 fps | 98.5% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 53,838 psi | 88% | 2759 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 51,822 psi | 85% | 2671 fps | 99.3% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 52,678 psi | 86% | 2694 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 54,592 psi | 90% | 2605 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 54,853 psi | 90% | 2608 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 53,925 psi | 89% | 2657 fps | 98.1% |
| Somchem S321 | <<locked>> | 82% | 54,375 psi | 89% | 2703 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 53,969 psi | 89% | 2605 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 55,056 psi | 90% | 2713 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 52,562 psi | 86% | 2700 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 50,270 psi | 83% | 2762 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 46,876 psi | 77% | 2648 fps | 96.3% |
| Unknown powder | <<locked>> | 96% | 53,679 psi | 88% | 2769 fps | 99.5% |
| Vihtavuori N130 | <<locked>> | 82% | 54,476 psi | 89% | 2569 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 54,839 psi | 90% | 2592 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 53,258 psi | 87% | 2631 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 54,099 psi | 89% | 2648 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 54,027 psi | 89% | 2677 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 55,085 psi | 90% | 2759 fps | 99.8% |
| Vihtavuori N530 | <<locked>> | 84% | 53,780 psi | 88% | 2674 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 52,156 psi | 86% | 2644 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 53,998 psi | 89% | 2762 fps | 99.7% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 42,757 psi | 70% | 2651 fps | 99.1% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 51,721 psi | 85% | 2687 fps | 100% |
| Winchester 748 | <<locked>> | 82% | 54,128 psi | 89% | 2726 fps | 100% |
| Winchester 760 | <<locked>> | 94% | 54,302 psi | 89% | 2795 fps | 98.4% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 35,012 psi | 57% | 2589 fps | 99.2% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 80% | 48,863 psi | 80% | 2533 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 41,611 psi | 68% | 2467 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 47,036 psi | 77% | 2598 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 44,512 psi | 73% | 2500 fps | 95.3% |
| Accurate 3100 | <<locked>> | 98% | 38,116 psi | 63% | 2497 fps | 95.7% |
| Accurate 4064 | <<locked>> | 80% | 39,334 psi | 65% | 2464 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 30,777 psi | 51% | 2349 fps | 95% |
| ADI AR 2206H | <<locked>> | 80% | 45,078 psi | 74% | 2575 fps | 99.5% |
| ADI AR 2208 | <<locked>> | 80% | 38,348 psi | 63% | 2431 fps | 98% |
| ADI Benchmark 8208 | <<locked>> | 80% | 47,108 psi | 77% | 2579 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 47,427 psi | 78% | 2559 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 40,814 psi | 67% | 2605 fps | 98.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 37,855 psi | 62% | 2451 fps | 99.1% |
| Alliant Reloder-15 | <<locked>> | 80% | 40,756 psi | 67% | 2513 fps | 98.6% |
| Alliant Reloder-16 | <<locked>> | 82% | 31,357 psi | 51% | 2359 fps | 95.1% |
| Alliant Reloder-17 | 71.8 gr | 80% | 32,692 psi | 54% | 2428 fps | 97.6% |
| Alliant Reloder-23 | <<locked>> | 90% | 28,805 psi | 47% | 2323 fps | 95.7% |
| Alliant Reloder-26 | <<locked>> | 94% | 35,375 psi | 58% | 2552 fps | 96% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 44,208 psi | 73% | 2579 fps | 98.8% |
| Bofors RP3 | <<locked>> | 80% | 37,536 psi | 62% | 2457 fps | 99.1% |
| Bofors RP7 | <<locked>> | 88% | 43,656 psi | 72% | 2530 fps | 95.4% |
| Hodgdon Benchmark | <<locked>> | 80% | 48,733 psi | 80% | 2562 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 45,890 psi | 75% | 2602 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 50,662 psi | 83% | 2740 fps | 99.8% |
| Hodgdon H322 | <<locked>> | 80% | 50,111 psi | 82% | 2608 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 38,450 psi | 63% | 2461 fps | 97% |
| Hodgdon H414 | <<locked>> | 86% | 41,263 psi | 68% | 2572 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 92% | 45,716 psi | 75% | 2605 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 45,469 psi | 75% | 2582 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 26,977 psi | 44% | 2215 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 39,073 psi | 64% | 2513 fps | 99.4% |
| Hodgdon Superformance | <<locked>> | 90% | 43,033 psi | 71% | 2628 fps | 95.4% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,527 psi | 44% | 1470 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 40,335 psi | 66% | 2477 fps | 99.2% |
| IMR 3031 | <<locked>> | 80% | 41,452 psi | 68% | 2513 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 37,579 psi | 62% | 2408 fps | 98% |
| IMR 4166 Enduron | <<locked>> | 84% | 42,148 psi | 69% | 2470 fps | 95.6% |
| IMR 4350 | <<locked>> | 92% | 43,758 psi | 72% | 2556 fps | 95.5% |
| IMR 4451 Enduron | <<locked>> | 86% | 42,641 psi | 70% | 2510 fps | 95.6% |
| IMR 4831 | <<locked>> | 86% | 30,908 psi | 51% | 2333 fps | 95.1% |
| IMR 4895 | <<locked>> | 80% | 41,756 psi | 69% | 2543 fps | 99.2% |
| IMR 8208 XBR | <<locked>> | 80% | 47,108 psi | 77% | 2579 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 44,106 psi | 72% | 2549 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 44,991 psi | 74% | 2510 fps | 99.5% |
| Lovex S062 | <<locked>> | 80% | 40,147 psi | 66% | 2467 fps | 99.6% |
| Lovex S065 | <<locked>> | 84% | 37,289 psi | 61% | 2411 fps | 95.7% |
| Lovex S070 | <<locked>> | 88% | 40,074 psi | 66% | 2490 fps | 95.3% |
| Norma 201 | <<locked>> | 80% | 44,150 psi | 72% | 2526 fps | 99.9% |
| Norma 202 | <<locked>> | 80% | 44,324 psi | 73% | 2530 fps | 100% |
| Norma 203B | <<locked>> | 80% | 40,132 psi | 66% | 2503 fps | 98.9% |
| Norma 204 | <<locked>> | 96% | 49,632 psi | 81% | 2694 fps | 95.5% |
| Norma MRP | <<locked>> | 98% | 40,814 psi | 67% | 2635 fps | 95% |
| Norma URP | <<locked>> | 82% | 31,299 psi | 51% | 2349 fps | 95% |
| Ramshot Big Game | <<locked>> | 80% | 39,537 psi | 65% | 2513 fps | 98.7% |
| Ramshot Hunter | <<locked>> | 88% | 37,173 psi | 61% | 2493 fps | 95.1% |
| Ramshot TAC | <<locked>> | 80% | 46,876 psi | 77% | 2585 fps | 98.2% |
| Ramshot Wild Boar | <<locked>> | 80% | 46,543 psi | 76% | 2608 fps | 99.7% |
| Ramshot X-Terminator | <<locked>> | 80% | 50,749 psi | 83% | 2625 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,818 psi | 44% | 1503 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 38,783 psi | 64% | 2444 fps | 95.3% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 42,859 psi | 70% | 2612 fps | 99% |
| ReloadSwiss RS 60 | 71.8 gr | 80% | 34,780 psi | 57% | 2487 fps | 99.8% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 32,735 psi | 54% | 2415 fps | 95.3% |
| ReloadSwiss RS 70 | 78.4 gr | 86% | 35,215 psi | 58% | 2477 fps | 95.3% |
| Rottweil R 901 | <<locked>> | 80% | 48,022 psi | 79% | 2559 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,003 psi | 69% | 2480 fps | 99.8% |
| Rottweil R 903 | <<locked>> | 80% | 35,331 psi | 58% | 2405 fps | 98.5% |
| Rottweil R 907 | <<locked>> | 88% | 43,656 psi | 72% | 2530 fps | 95.4% |
| Shooters World Long Rifle | <<locked>> | 84% | 37,289 psi | 61% | 2411 fps | 95.7% |
| Shooters World Match Rifle | <<locked>> | 80% | 44,106 psi | 72% | 2549 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 40,147 psi | 66% | 2467 fps | 99.6% |
| Shooters World SW4350 | <<locked>> | 88% | 40,074 psi | 66% | 2490 fps | 95.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 36,274 psi | 60% | 2454 fps | 98.1% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 45,368 psi | 74% | 2566 fps | 98.4% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 43,497 psi | 71% | 2543 fps | 99.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 45,353 psi | 74% | 2474 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 37,768 psi | 62% | 2349 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 41,742 psi | 69% | 2461 fps | 95.6% |
| Somchem S321 | <<locked>> | 80% | 50,952 psi | 84% | 2654 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 45,063 psi | 74% | 2477 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 45,020 psi | 74% | 2559 fps | 99.5% |
| Somchem S355 | <<locked>> | 80% | 36,230 psi | 59% | 2411 fps | 98.5% |
| Somchem S365 | <<locked>> | 80% | 26,310 psi | 43% | 2254 fps | 96.4% |
| Somchem S385 | <<locked>> | 98% | 43,918 psi | 72% | 2598 fps | 95.5% |
| Unknown powder | <<locked>> | 82% | 34,055 psi | 56% | 2405 fps | 95.3% |
| Vihtavuori N130 | <<locked>> | 80% | 51,155 psi | 84% | 2526 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 45,701 psi | 75% | 2464 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 41,452 psi | 68% | 2457 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 41,989 psi | 69% | 2470 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 34,403 psi | 56% | 2349 fps | 99.1% |
| Vihtavuori N160 | <<locked>> | 82% | 32,721 psi | 54% | 2352 fps | 95.5% |
| Vihtavuori N530 | <<locked>> | 80% | 47,152 psi | 77% | 2572 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 40,553 psi | 67% | 2464 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 32,126 psi | 53% | 2356 fps | 95% |
| Vihtavuori N555 | <<locked>> | 90% | 30,864 psi | 51% | 2395 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 30,516 psi | 50% | 2280 fps | 96.9% |
| Winchester 748 | <<locked>> | 80% | 50,575 psi | 83% | 2674 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 41,263 psi | 68% | 2572 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 92% | 27,137 psi | 45% | 2339 fps | 95% |
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 119 powders for .375 Blaser Mag. loaded with the .375 | 270gr | Speer Boat-Tail. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 2,835 fps; across all powders the maximum-charge window runs from 1,644 fps to 2,835 fps. Accurate 3100 gives the best case fill at 100 %, and 119 of the 119 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (420 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 270.0 gr projectile in 0.375" calls for a 1:6.0 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 Reloder-17, ReloadSwiss RS 60, ReloadSwiss RS 70 rank at the top here: for .375 Blaser Mag. with the .375 | 270gr | Speer Boat-Tail 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.