Load Specifications
Load data in caliber .270 Win. with .277 | 150gr | Peregrine VRG-3 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-17 and ReloadSwiss RS 60.
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 2495 | <<locked>> | 84% | 54,534 psi | 87% | 2667 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 53,069 psi | 85% | 2687 fps | 98.3% |
| Accurate 3100ᴾ | <<locked>> | 100% | 49,226 psi | 79% | 2710 fps | 99% |
| Accurate 4064 | <<locked>> | 86% | 54,679 psi | 88% | 2717 fps | 100% |
| Accurate 4350 | <<locked>> | 94% | 55,347 psi | 89% | 2818 fps | 100% |
| ADI AR 2206H | <<locked>> | 82% | 54,607 psi | 88% | 2753 fps | 100% |
| ADI AR 2208 | <<locked>> | 88% | 55,622 psi | 89% | 2756 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 53,214 psi | 85% | 2808 fps | 97.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 54,926 psi | 88% | 2877 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 56,362 psi | 90% | 2779 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 86% | 56,376 psi | 90% | 2795 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 53,040 psi | 85% | 2828 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 90% | 54,259 psi | 87% | 2854 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 55,927 psi | 90% | 2851 fps | 98.2% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 49,342 psi | 79% | 2792 fps | 97.2% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 46,441 psi | 74% | 2733 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 40,524 psi | 65% | 2648 fps | 98.1% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 53,098 psi | 85% | 2920 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 54,476 psi | 87% | 2769 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 45,165 psi | 72% | 2713 fps | 95.9% |
| Bofors RP3 | <<locked>> | 86% | 53,388 psi | 86% | 2743 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 49,342 psi | 79% | 2792 fps | 97.2% |
| Bofors RP7 | <<locked>> | 90% | 52,968 psi | 85% | 2723 fps | 98.4% |
| Hodgdon H380 | <<locked>> | 86% | 53,983 psi | 87% | 2759 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 92% | 54,534 psi | 87% | 2825 fps | 99.1% |
| Hodgdon H4350 | <<locked>> | 90% | 54,607 psi | 88% | 2785 fps | 98.2% |
| Hodgdon H4831ᴾ | <<locked>> | 100% | 54,795 psi | 88% | 2805 fps | 96% |
| Hodgdon H4895 | <<locked>> | 82% | 55,216 psi | 89% | 2759 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 53,098 psi | 85% | 2753 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 55,201 psi | 89% | 2795 fps | 100% |
| Hodgdon Superformance | <<locked>> | 92% | 54,476 psi | 87% | 2858 fps | 99% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,129 psi | 58% | 1699 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 56,246 psi | 90% | 2759 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 55,521 psi | 89% | 2733 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 55,274 psi | 89% | 2740 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 54,505 psi | 87% | 2723 fps | 99% |
| IMR 4350 | <<locked>> | 94% | 54,041 psi | 87% | 2759 fps | 98.6% |
| IMR 4451 Enduron | <<locked>> | 90% | 55,085 psi | 88% | 2756 fps | 99% |
| IMR 4831 | <<locked>> | 96% | 56,028 psi | 90% | 2815 fps | 100% |
| IMR 4895 | <<locked>> | 84% | 54,607 psi | 88% | 2779 fps | 100% |
| IMR 4955 Enduronᴾ | <<locked>> | 100% | 56,376 psi | 90% | 2795 fps | 96.5% |
| Lovex D073.6 | <<locked>> | 82% | 54,476 psi | 87% | 2720 fps | 100% |
| Lovex S060 | <<locked>> | 82% | 53,490 psi | 86% | 2677 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 55,216 psi | 89% | 2730 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 54,462 psi | 87% | 2746 fps | 99.7% |
| Lovex S070 | <<locked>> | 94% | 55,883 psi | 90% | 2789 fps | 99.3% |
| Lovex S071ᴾ | <<locked>> | 100% | 40,669 psi | 65% | 2562 fps | 97.4% |
| Norma 201 | <<locked>> | 82% | 53,156 psi | 85% | 2694 fps | 100% |
| Norma 202 | <<locked>> | 82% | 53,795 psi | 86% | 2690 fps | 100% |
| Norma 203B | <<locked>> | 86% | 55,622 psi | 89% | 2782 fps | 100% |
| Norma 204 | <<locked>> | 94% | 54,505 psi | 87% | 2805 fps | 97.7% |
| Norma MRPᴾ | <<locked>> | 100% | 52,359 psi | 84% | 2877 fps | 98.9% |
| Norma URP | <<locked>> | 94% | 54,476 psi | 87% | 2808 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 53,113 psi | 85% | 2762 fps | 100% |
| Ramshot Hunter | <<locked>> | 94% | 53,171 psi | 85% | 2808 fps | 99.5% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,564 psi | 59% | 1739 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 53,882 psi | 86% | 2743 fps | 99.3% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 53,751 psi | 86% | 2812 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 53,693 psi | 86% | 2848 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 55,419 psi | 89% | 2844 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 54,273 psi | 87% | 2874 fps | 100% |
| Rottweil R 902 | <<locked>> | 84% | 53,722 psi | 86% | 2694 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 53,229 psi | 85% | 2733 fps | 100% |
| Rottweil R 904 | <<locked>> | 98% | 55,201 psi | 89% | 2785 fps | 96.9% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 55,056 psi | 88% | 2838 fps | 98.2% |
| Rottweil R 907 | <<locked>> | 90% | 52,968 psi | 85% | 2723 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 92% | 54,462 psi | 87% | 2746 fps | 99.7% |
| Shooters World Match Rifle | <<locked>> | 82% | 54,476 psi | 87% | 2720 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 55,216 psi | 89% | 2730 fps | 100% |
| Shooters World SW4350 | <<locked>> | 94% | 55,883 psi | 90% | 2789 fps | 99.3% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 55,071 psi | 88% | 2795 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 55,463 psi | 89% | 2753 fps | 99.9% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 52,881 psi | 85% | 2720 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 54,172 psi | 87% | 2628 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 54,955 psi | 88% | 2631 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 54,288 psi | 87% | 2700 fps | 99% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 54,563 psi | 87% | 2831 fps | 98.1% |
| Somchem S335 | <<locked>> | 82% | 53,882 psi | 86% | 2628 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 55,419 psi | 89% | 2743 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 53,505 psi | 86% | 2733 fps | 100% |
| Somchem S365 | <<locked>> | 96% | 53,098 psi | 85% | 2808 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 55,637 psi | 89% | 2815 fps | 98.8% |
| Vihtavuori N133 | <<locked>> | 82% | 54,752 psi | 88% | 2612 fps | 100% |
| Vihtavuori N135 | <<locked>> | 84% | 53,853 psi | 86% | 2654 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 54,621 psi | 88% | 2674 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 54,853 psi | 88% | 2710 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 53,011 psi | 85% | 2753 fps | 99.9% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 47,935 psi | 77% | 2680 fps | 97.2% |
| Vihtavuori N540 | <<locked>> | 86% | 56,159 psi | 90% | 2717 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 55,854 psi | 90% | 2812 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 52,141 psi | 84% | 2812 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 52,939 psi | 85% | 2864 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 52,895 psi | 85% | 2726 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 54,534 psi | 87% | 2825 fps | 99.1% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 41,713 psi | 67% | 2779 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 52,953 psi | 85% | 2730 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 52,388 psi | 84% | 2756 fps | 97.4% |
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% | 47,616 psi | 76% | 2572 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 46,456 psi | 74% | 2575 fps | 97% |
| Accurate 3100 | <<locked>> | 90% | 34,679 psi | 56% | 2438 fps | 95.6% |
| Accurate 4064 | <<locked>> | 80% | 45,107 psi | 72% | 2575 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 34,011 psi | 55% | 2434 fps | 97.1% |
| ADI AR 2206H | <<locked>> | 80% | 51,227 psi | 82% | 2700 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 43,482 psi | 70% | 2556 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 92% | 43,845 psi | 70% | 2641 fps | 95.3% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 47,456 psi | 76% | 2756 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 43,424 psi | 70% | 2575 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 46,731 psi | 75% | 2644 fps | 99.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 33,707 psi | 54% | 2448 fps | 97.3% |
| Alliant Reloder-17 | 46 gr | 80% | 38,014 psi | 61% | 2569 fps | 99.6% |
| Alliant Reloder-19 | <<locked>> | 92% | 43,091 psi | 69% | 2631 fps | 95.3% |
| Alliant Reloder-22 | <<locked>> | 96% | 43,149 psi | 69% | 2677 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 82% | 25,991 psi | 42% | 2254 fps | 95.2% |
| Alliant Reloder-25 | <<locked>> | 94% | 33,576 psi | 54% | 2480 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 86% | 31,807 psi | 51% | 2480 fps | 95.7% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 50,836 psi | 82% | 2713 fps | 99.9% |
| Bofors RP15 | <<locked>> | 98% | 42,250 psi | 68% | 2657 fps | 95% |
| Bofors RP3 | <<locked>> | 80% | 43,381 psi | 70% | 2582 fps | 100% |
| Bofors RP5 | <<locked>> | 96% | 43,149 psi | 69% | 2677 fps | 95.5% |
| Bofors RP7 | <<locked>> | 80% | 38,493 psi | 62% | 2457 fps | 95% |
| Hodgdon H380 | <<locked>> | 80% | 44,063 psi | 71% | 2595 fps | 99% |
| Hodgdon H414 | <<locked>> | 82% | 38,725 psi | 62% | 2539 fps | 95.8% |
| Hodgdon H4350 | <<locked>> | 82% | 41,930 psi | 67% | 2562 fps | 95.3% |
| Hodgdon H4831 | <<locked>> | 98% | 51,198 psi | 82% | 2749 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 51,764 psi | 83% | 2710 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 31,082 psi | 50% | 2346 fps | 97.9% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 48,138 psi | 77% | 2687 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 40,814 psi | 65% | 2612 fps | 96% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,919 psi | 43% | 1519 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 49,458 psi | 79% | 2661 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 52,185 psi | 84% | 2687 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 45,730 psi | 73% | 2589 fps | 99.8% |
| IMR 4166 Enduron | <<locked>> | 80% | 48,037 psi | 77% | 2615 fps | 98.1% |
| IMR 4350 | <<locked>> | 84% | 39,204 psi | 63% | 2493 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 80% | 40,059 psi | 64% | 2490 fps | 96% |
| IMR 4831 | <<locked>> | 80% | 32,909 psi | 53% | 2392 fps | 96.8% |
| IMR 4895 | <<locked>> | 80% | 47,921 psi | 77% | 2674 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 49,617 psi | 80% | 2687 fps | 95% |
| Lovex D073.6 | <<locked>> | 80% | 51,024 psi | 82% | 2674 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 50,517 psi | 81% | 2631 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 45,745 psi | 73% | 2585 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 37,492 psi | 60% | 2441 fps | 96.8% |
| Lovex S070 | <<locked>> | 80% | 35,708 psi | 57% | 2418 fps | 95% |
| Lovex S071 | <<locked>> | 94% | 33,359 psi | 53% | 2405 fps | 95% |
| Norma 201 | <<locked>> | 80% | 49,792 psi | 80% | 2644 fps | 100% |
| Norma 202 | <<locked>> | 80% | 50,401 psi | 81% | 2641 fps | 100% |
| Norma 203B | <<locked>> | 80% | 46,079 psi | 74% | 2631 fps | 99.9% |
| Norma 204 | <<locked>> | 88% | 44,324 psi | 71% | 2631 fps | 95.4% |
| Norma MRP | <<locked>> | 92% | 39,494 psi | 63% | 2631 fps | 95.9% |
| Norma URP | <<locked>> | 80% | 34,185 psi | 55% | 2434 fps | 97% |
| Ramshot Big Game | <<locked>> | 80% | 46,064 psi | 74% | 2651 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 82% | 35,447 psi | 57% | 2474 fps | 95.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,369 psi | 44% | 1555 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 44,237 psi | 71% | 2579 fps | 97.8% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 50,212 psi | 81% | 2756 fps | 100% |
| ReloadSwiss RS 60 | 46 gr | 80% | 40,466 psi | 65% | 2628 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 33,852 psi | 54% | 2451 fps | 96.7% |
| ReloadSwiss RS 70 | 46.7 gr | 80% | 33,185 psi | 53% | 2451 fps | 95.8% |
| Rottweil R 902 | <<locked>> | 80% | 47,471 psi | 76% | 2598 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 40,959 psi | 66% | 2533 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 94% | 48,385 psi | 78% | 2674 fps | 95.4% |
| Rottweil R 905 | <<locked>> | 92% | 42,163 psi | 68% | 2615 fps | 95.3% |
| Rottweil R 907 | <<locked>> | 80% | 38,493 psi | 62% | 2457 fps | 95% |
| Shooters World Long Rifle | <<locked>> | 80% | 37,492 psi | 60% | 2441 fps | 96.8% |
| Shooters World Match Rifle | <<locked>> | 80% | 51,024 psi | 82% | 2674 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 45,745 psi | 73% | 2585 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 35,708 psi | 57% | 2418 fps | 95% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 42,206 psi | 68% | 2585 fps | 99.6% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 51,996 psi | 83% | 2700 fps | 99.8% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 49,647 psi | 80% | 2671 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 51,039 psi | 82% | 2585 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 42,888 psi | 69% | 2457 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 36,782 psi | 59% | 2388 fps | 95.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 41,756 psi | 67% | 2608 fps | 95.1% |
| Somchem S335 | <<locked>> | 80% | 50,560 psi | 81% | 2582 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 51,706 psi | 83% | 2690 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 41,452 psi | 66% | 2533 fps | 99.8% |
| Somchem S365 | <<locked>> | 80% | 30,560 psi | 49% | 2388 fps | 98.9% |
| Somchem S385 | <<locked>> | 90% | 39,929 psi | 64% | 2543 fps | 95.5% |
| Vihtavuori N133 | <<locked>> | 80% | 51,590 psi | 83% | 2572 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 47,645 psi | 76% | 2569 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 47,950 psi | 77% | 2582 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 39,581 psi | 63% | 2470 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 35,665 psi | 57% | 2438 fps | 97.5% |
| Vihtavuori N165 | <<locked>> | 96% | 41,887 psi | 67% | 2572 fps | 95.6% |
| Vihtavuori N540 | <<locked>> | 80% | 46,151 psi | 74% | 2572 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 34,954 psi | 56% | 2434 fps | 97% |
| Vihtavuori N555 | <<locked>> | 82% | 28,297 psi | 45% | 2326 fps | 95.4% |
| Vihtavuori N560 | <<locked>> | 98% | 49,530 psi | 79% | 2805 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 34,911 psi | 56% | 2411 fps | 99.1% |
| Winchester 760 | <<locked>> | 80% | 36,448 psi | 58% | 2487 fps | 95% |
| Winchester StaBALL HD | <<locked>> | 86% | 26,020 psi | 42% | 2333 fps | 95.9% |
| Winchester StaBALL Match | <<locked>> | 80% | 49,356 psi | 79% | 2674 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 42,279 psi | 68% | 2582 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 97 powders for .270 Win. loaded with the .277 | 150gr | Peregrine VRG-3. Alliant Reloder-26 delivers the highest muzzle velocity at 2,920 fps; across all powders the maximum-charge window runs from 1,699 fps to 2,920 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 150.0 gr projectile in 0.277" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-19, 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-17, ReloadSwiss RS 60 rank at the top here: for .270 Win. with the .277 | 150gr | Peregrine VRG-3 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.