Load Specifications
Load data in caliber .270 Win. with .277 | 135gr | Peregrine Glider GRM bullet and 97 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 Winchester 760.
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 2015 | <<locked>> | 84% | 55,651 psi | 89% | 2776 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 54,070 psi | 87% | 2799 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 56,246 psi | 90% | 2867 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 53,606 psi | 86% | 2802 fps | 96.9% |
| Accurate 3100ᴾ | <<locked>> | 100% | 41,481 psi | 67% | 2690 fps | 96.1% |
| Accurate 4064 | <<locked>> | 90% | 54,462 psi | 87% | 2848 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 54,607 psi | 88% | 2936 fps | 99.7% |
| ADI AR 2206H | <<locked>> | 86% | 55,056 psi | 88% | 2884 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 56,115 psi | 90% | 2884 fps | 99.9% |
| ADI Benchmark 8208 | <<locked>> | 84% | 53,925 psi | 86% | 2831 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 54,969 psi | 88% | 2808 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 55,100 psi | 88% | 3009 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 56,362 psi | 90% | 2907 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 53,113 psi | 85% | 2874 fps | 99.8% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 56,072 psi | 90% | 2999 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 94% | 53,606 psi | 86% | 2979 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 39,813 psi | 64% | 2726 fps | 99% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 44,802 psi | 72% | 2890 fps | 98.4% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 54,897 psi | 88% | 2897 fps | 99.7% |
| Bofors RP3 | <<locked>> | 90% | 53,127 psi | 85% | 2867 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 53,461 psi | 86% | 2841 fps | 97.2% |
| Hodgdon Benchmark | <<locked>> | 84% | 55,782 psi | 89% | 2818 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 53,330 psi | 86% | 2861 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 55,622 psi | 89% | 2966 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 90% | 54,099 psi | 87% | 2881 fps | 99.4% |
| Hodgdon H414 | <<locked>> | 96% | 53,809 psi | 86% | 2933 fps | 97.9% |
| Hodgdon H4350 | <<locked>> | 94% | 54,549 psi | 87% | 2897 fps | 96.7% |
| Hodgdon H4895 | <<locked>> | 86% | 55,622 psi | 89% | 2894 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 52,069 psi | 83% | 2867 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 55,274 psi | 89% | 2930 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 54,549 psi | 87% | 2969 fps | 97.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,534 psi | 57% | 1762 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 53,330 psi | 86% | 2844 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 55,796 psi | 89% | 2874 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 55,637 psi | 89% | 2867 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 88% | 55,608 psi | 89% | 2848 fps | 98% |
| IMR 4350 | <<locked>> | 98% | 53,795 psi | 86% | 2867 fps | 97.3% |
| IMR 4451 Enduron | <<locked>> | 94% | 55,390 psi | 89% | 2874 fps | 98% |
| IMR 4831ᴾ | <<locked>> | 100% | 55,201 psi | 89% | 2930 fps | 99.7% |
| IMR 4895 | <<locked>> | 88% | 54,491 psi | 87% | 2904 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 53,925 psi | 86% | 2831 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 54,868 psi | 88% | 2858 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 54,694 psi | 88% | 2812 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 55,303 psi | 89% | 2861 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 54,491 psi | 87% | 2861 fps | 98.9% |
| Lovex S070 | <<locked>> | 98% | 55,521 psi | 89% | 2900 fps | 98.3% |
| Norma 201 | <<locked>> | 86% | 53,577 psi | 86% | 2825 fps | 100% |
| Norma 202 | <<locked>> | 86% | 54,476 psi | 87% | 2831 fps | 100% |
| Norma 203B | <<locked>> | 90% | 55,970 psi | 90% | 2913 fps | 100% |
| Norma 204 | <<locked>> | 98% | 54,592 psi | 88% | 2917 fps | 96.2% |
| Norma URP | <<locked>> | 98% | 53,635 psi | 86% | 2923 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 88% | 53,214 psi | 85% | 2890 fps | 99.9% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 56,072 psi | 90% | 2976 fps | 98.9% |
| Ramshot TAC | <<locked>> | 84% | 54,331 psi | 87% | 2851 fps | 99% |
| Ramshot Wild Boar | <<locked>> | 84% | 54,085 psi | 87% | 2874 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 54,853 psi | 88% | 2835 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,868 psi | 58% | 1801 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 54,549 psi | 87% | 2867 fps | 98.4% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 53,882 psi | 86% | 2943 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 53,316 psi | 85% | 2976 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 54,259 psi | 87% | 2959 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 53,911 psi | 86% | 2986 fps | 99.4% |
| Rottweil R 901 | <<locked>> | 84% | 54,288 psi | 87% | 2805 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 54,201 psi | 87% | 2828 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 53,011 psi | 85% | 2861 fps | 100% |
| Rottweil R 907 | <<locked>> | 94% | 53,461 psi | 86% | 2841 fps | 97.2% |
| Shooters World Long Rifle | <<locked>> | 96% | 54,491 psi | 87% | 2861 fps | 98.9% |
| Shooters World Match Rifle | <<locked>> | 86% | 54,868 psi | 88% | 2858 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 55,303 psi | 89% | 2861 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 55,521 psi | 89% | 2900 fps | 98.3% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 54,969 psi | 88% | 2923 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 52,779 psi | 85% | 2831 fps | 99.2% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 53,635 psi | 86% | 2854 fps | 99.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 55,085 psi | 88% | 2766 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 55,535 psi | 89% | 2766 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 54,795 psi | 88% | 2815 fps | 97.9% |
| Somchem S321 | <<locked>> | 82% | 55,317 psi | 89% | 2867 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 54,534 psi | 87% | 2766 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 55,985 psi | 90% | 2874 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 53,476 psi | 86% | 2861 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 51,547 psi | 83% | 2923 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 47,921 psi | 77% | 2802 fps | 96% |
| Vihtavuori N130 | <<locked>> | 82% | 55,085 psi | 88% | 2730 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 55,448 psi | 89% | 2749 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 53,925 psi | 86% | 2789 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 54,781 psi | 88% | 2808 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 55,129 psi | 88% | 2841 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 56,376 psi | 90% | 2923 fps | 99.7% |
| Vihtavuori N530 | <<locked>> | 84% | 54,418 psi | 87% | 2831 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 52,910 psi | 85% | 2802 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 55,259 psi | 89% | 2927 fps | 99.6% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 43,772 psi | 70% | 2802 fps | 98.9% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 53,069 psi | 85% | 2851 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 54,549 psi | 87% | 2881 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 54,114 psi | 87% | 2936 fps | 98% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 35,447 psi | 57% | 2723 fps | 98.9% |
| Winchester StaBALL Match | <<locked>> | 86% | 53,243 psi | 85% | 2861 fps | 100% |
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% | 49,081 psi | 79% | 2684 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 41,394 psi | 66% | 2602 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 48,994 psi | 79% | 2762 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 47,181 psi | 76% | 2694 fps | 95.5% |
| Accurate 3100 | <<locked>> | 98% | 38,754 psi | 62% | 2635 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 39,160 psi | 63% | 2598 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 33,069 psi | 53% | 2523 fps | 95.1% |
| ADI AR 2206H | <<locked>> | 80% | 45,310 psi | 73% | 2720 fps | 99.3% |
| ADI AR 2208 | <<locked>> | 80% | 38,566 psi | 62% | 2569 fps | 97.6% |
| ADI Benchmark 8208 | <<locked>> | 80% | 47,427 psi | 76% | 2730 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 80% | 48,167 psi | 77% | 2713 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 41,510 psi | 67% | 2756 fps | 98.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 38,305 psi | 61% | 2592 fps | 98.8% |
| Alliant Reloder-15 | <<locked>> | 80% | 40,930 psi | 66% | 2654 fps | 98.3% |
| Alliant Reloder-16 | <<locked>> | 84% | 33,649 psi | 54% | 2546 fps | 95.4% |
| Alliant Reloder-17 | 44 gr | 80% | 32,982 psi | 53% | 2556 fps | 97% |
| Alliant Reloder-23 | <<locked>> | 92% | 30,879 psi | 50% | 2500 fps | 96% |
| Alliant Reloder-26 | <<locked>> | 94% | 35,984 psi | 58% | 2687 fps | 95.5% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 44,686 psi | 72% | 2726 fps | 98.5% |
| Bofors RP3 | <<locked>> | 80% | 37,768 psi | 61% | 2592 fps | 98.8% |
| Bofors RP7 | <<locked>> | 88% | 44,135 psi | 71% | 2674 fps | 95% |
| Hodgdon Benchmark | <<locked>> | 80% | 49,226 psi | 79% | 2717 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 46,543 psi | 75% | 2753 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 51,605 psi | 83% | 2900 fps | 99.7% |
| Hodgdon H380 | <<locked>> | 80% | 38,769 psi | 62% | 2598 fps | 96.5% |
| Hodgdon H414 | <<locked>> | 90% | 43,990 psi | 71% | 2759 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 90% | 48,008 psi | 77% | 2785 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 45,716 psi | 73% | 2730 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 28,848 psi | 46% | 2388 fps | 95.3% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 41,916 psi | 67% | 2703 fps | 99.5% |
| Hodgdon Superformance | <<locked>> | 90% | 43,816 psi | 70% | 2776 fps | 95% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,252 psi | 42% | 1572 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 43,990 psi | 71% | 2684 fps | 99.4% |
| IMR 3031 | <<locked>> | 80% | 45,585 psi | 73% | 2723 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 40,466 psi | 65% | 2602 fps | 98.2% |
| IMR 4166 Enduron | <<locked>> | 80% | 43,149 psi | 69% | 2628 fps | 95.3% |
| IMR 4350 | <<locked>> | 92% | 44,527 psi | 71% | 2703 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 86% | 43,323 psi | 69% | 2661 fps | 95.3% |
| IMR 4831 | <<locked>> | 86% | 34,563 psi | 55% | 2543 fps | 95.8% |
| IMR 4895 | <<locked>> | 80% | 41,959 psi | 67% | 2684 fps | 98.9% |
| IMR 8208 XBR | <<locked>> | 80% | 47,427 psi | 76% | 2730 fps | 99.9% |
| Lovex D073.6 | <<locked>> | 80% | 44,512 psi | 71% | 2697 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 45,353 psi | 73% | 2657 fps | 99.4% |
| Lovex S062 | <<locked>> | 80% | 40,306 psi | 65% | 2605 fps | 99.4% |
| Lovex S065 | <<locked>> | 84% | 37,536 psi | 60% | 2546 fps | 95.2% |
| Lovex S070 | <<locked>> | 90% | 43,149 psi | 69% | 2684 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 44,208 psi | 71% | 2671 fps | 99.8% |
| Norma 202 | <<locked>> | 80% | 44,889 psi | 72% | 2680 fps | 100% |
| Norma 203B | <<locked>> | 80% | 40,321 psi | 65% | 2641 fps | 98.6% |
| Norma 204 | <<locked>> | 96% | 50,894 psi | 82% | 2854 fps | 95.3% |
| Norma URP | <<locked>> | 84% | 33,750 psi | 54% | 2536 fps | 95.2% |
| Ramshot Big Game | <<locked>> | 80% | 40,176 psi | 64% | 2657 fps | 98.4% |
| Ramshot Hunter | <<locked>> | 90% | 40,161 psi | 64% | 2687 fps | 95.5% |
| Ramshot TAC | <<locked>> | 80% | 47,398 psi | 76% | 2736 fps | 98% |
| Ramshot Wild Boar | <<locked>> | 80% | 47,065 psi | 75% | 2756 fps | 99.5% |
| Ramshot X-Terminator | <<locked>> | 80% | 51,430 psi | 82% | 2782 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,629 psi | 43% | 1611 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 41,785 psi | 67% | 2638 fps | 95.7% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 43,468 psi | 70% | 2762 fps | 98.7% |
| ReloadSwiss RS 60 | 44 gr | 80% | 35,143 psi | 56% | 2625 fps | 99.6% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 35,389 psi | 57% | 2602 fps | 95.6% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 38,276 psi | 61% | 2677 fps | 95.9% |
| Rottweil R 901 | <<locked>> | 80% | 47,993 psi | 77% | 2707 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,032 psi | 67% | 2621 fps | 99.6% |
| Rottweil R 903 | <<locked>> | 80% | 35,520 psi | 57% | 2536 fps | 98.1% |
| Rottweil R 907 | <<locked>> | 88% | 44,135 psi | 71% | 2674 fps | 95% |
| Shooters World Long Rifle | <<locked>> | 84% | 37,536 psi | 60% | 2546 fps | 95.2% |
| Shooters World Match Rifle | <<locked>> | 80% | 44,512 psi | 71% | 2697 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 40,306 psi | 65% | 2605 fps | 99.4% |
| Shooters World SW4350 | <<locked>> | 90% | 43,149 psi | 69% | 2684 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 36,637 psi | 59% | 2585 fps | 97.6% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 45,730 psi | 73% | 2710 fps | 98.1% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 43,918 psi | 70% | 2690 fps | 99.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 45,876 psi | 74% | 2628 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,174 psi | 61% | 2490 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 42,032 psi | 67% | 2595 fps | 95.1% |
| Somchem S321 | <<locked>> | 80% | 51,430 psi | 82% | 2808 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 45,208 psi | 72% | 2621 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 45,469 psi | 73% | 2707 fps | 99.3% |
| Somchem S355 | <<locked>> | 80% | 36,289 psi | 58% | 2539 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 26,237 psi | 42% | 2362 fps | 95.4% |
| Somchem S385 | <<locked>> | 98% | 44,657 psi | 72% | 2743 fps | 95.1% |
| Vihtavuori N130 | <<locked>> | 80% | 51,779 psi | 83% | 2687 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 46,296 psi | 74% | 2618 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 41,916 psi | 67% | 2605 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 42,467 psi | 68% | 2615 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 34,606 psi | 55% | 2477 fps | 98.7% |
| Vihtavuori N160 | <<locked>> | 84% | 35,114 psi | 56% | 2536 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 47,703 psi | 76% | 2726 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 40,944 psi | 66% | 2605 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 34,635 psi | 56% | 2536 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 90% | 31,212 psi | 50% | 2520 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 30,589 psi | 49% | 2402 fps | 96.2% |
| Winchester 748 | <<locked>> | 80% | 47,529 psi | 76% | 2772 fps | 100% |
| Winchester 760 | 48.5 gr | 90% | 44,251 psi | 71% | 2762 fps | 95.8% |
| Winchester StaBALL HD | <<locked>> | 94% | 29,095 psi | 47% | 2520 fps | 95.5% |
| Winchester StaBALL Match | <<locked>> | 80% | 43,424 psi | 70% | 2694 fps | 99.4% |
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 97 powders for .270 Win. loaded with the .277 | 135gr | Peregrine Glider GRM. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,009 fps; across all powders the maximum-charge window runs from 1,762 fps to 3,009 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 57–90 %, leaving at least 10 % headroom. The 135.0 gr projectile in 0.277" calls for a 1:8.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-16, Alliant Reloder-23 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, Winchester 760 rank at the top here: for .270 Win. with the .277 | 135gr | Peregrine 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.