Load Specifications
Load data in caliber .270 Weath. Mag. with .277 | 100gr | Hornady GMX 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 60, Hodgdon H414 and Alliant Reloder-16.
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: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 82% | 55,869 psi | 88% | 3356 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 55,201 psi | 87% | 3379 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 57,276 psi | 90% | 3461 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 54,433 psi | 85% | 3379 fps | 96.9% |
| Accurate 3100ᴾ | <<locked>> | 100% | 47,181 psi | 74% | 3317 fps | 97.2% |
| Accurate 4064 | <<locked>> | 88% | 55,608 psi | 87% | 3435 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 56,884 psi | 89% | 3540 fps | 99.7% |
| ADI AR 2206H | <<locked>> | 84% | 55,448 psi | 87% | 3478 fps | 99.9% |
| ADI AR 2208 | <<locked>> | 90% | 56,942 psi | 89% | 3481 fps | 99.9% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 54,853 psi | 86% | 3510 fps | 96.2% |
| ADI Benchmark 8208 | <<locked>> | 82% | 54,244 psi | 85% | 3419 fps | 100% |
| Alliant AR-Comp | <<locked>> | 82% | 55,434 psi | 87% | 3392 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 56,188 psi | 88% | 3619 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 57,246 psi | 90% | 3504 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 57,595 psi | 90% | 3530 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 96% | 54,041 psi | 85% | 3547 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 92% | 55,434 psi | 87% | 3583 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 53,911 psi | 84% | 3494 fps | 96.1% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 44,338 psi | 69% | 3350 fps | 99.5% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 50,995 psi | 80% | 3560 fps | 99.3% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 55,782 psi | 87% | 3488 fps | 99.7% |
| Bofors RP3 | <<locked>> | 88% | 54,331 psi | 85% | 3458 fps | 100% |
| Bofors RP7 | <<locked>> | 92% | 54,433 psi | 85% | 3425 fps | 97.1% |
| Hodgdon Benchmark | <<locked>> | 82% | 55,608 psi | 87% | 3399 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 82% | 54,201 psi | 85% | 3448 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 55,201 psi | 87% | 3471 fps | 99.3% |
| Hodgdon H414 | <<locked>> | 94% | 55,811 psi | 87% | 3533 fps | 98% |
| Hodgdon H4350 | <<locked>> | 92% | 55,898 psi | 88% | 3491 fps | 96.8% |
| Hodgdon H4895 | <<locked>> | 84% | 56,086 psi | 88% | 3491 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 98% | 54,085 psi | 85% | 3458 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 56,347 psi | 88% | 3524 fps | 100% |
| Hodgdon Superformance | <<locked>> | 94% | 56,550 psi | 89% | 3573 fps | 98% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,636 psi | 56% | 2221 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 57,377 psi | 90% | 3491 fps | 100% |
| IMR 3031 | <<locked>> | 84% | 56,318 psi | 88% | 3471 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 56,202 psi | 88% | 3461 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 86% | 55,811 psi | 87% | 3432 fps | 97.9% |
| IMR 4350 | <<locked>> | 96% | 55,230 psi | 87% | 3455 fps | 97.4% |
| IMR 4451 Enduron | <<locked>> | 92% | 56,289 psi | 88% | 3465 fps | 97.9% |
| IMR 4831 | <<locked>> | 98% | 57,246 psi | 90% | 3527 fps | 99.8% |
| IMR 4895 | <<locked>> | 86% | 55,376 psi | 87% | 3501 fps | 100% |
| IMR 8208 XBR | <<locked>> | 82% | 54,244 psi | 85% | 3419 fps | 100% |
| Lovex D073.6 | <<locked>> | 84% | 55,622 psi | 87% | 3445 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 54,621 psi | 86% | 3392 fps | 99.9% |
| Lovex S062 | <<locked>> | 88% | 56,246 psi | 88% | 3455 fps | 100% |
| Lovex S065 | <<locked>> | 94% | 55,767 psi | 87% | 3451 fps | 98.9% |
| Lovex S070 | <<locked>> | 96% | 57,043 psi | 89% | 3494 fps | 98.3% |
| Norma 201 | <<locked>> | 86% | 57,580 psi | 90% | 3471 fps | 100% |
| Norma 202 | <<locked>> | 84% | 54,911 psi | 86% | 3415 fps | 100% |
| Norma 203B | <<locked>> | 88% | 56,811 psi | 89% | 3510 fps | 100% |
| Norma 204 | <<locked>> | 96% | 56,304 psi | 88% | 3514 fps | 96.3% |
| Norma MRPᴾ | <<locked>> | 100% | 50,241 psi | 79% | 3507 fps | 97% |
| Norma URP | <<locked>> | 96% | 55,535 psi | 87% | 3520 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 86% | 54,273 psi | 85% | 3474 fps | 99.9% |
| Ramshot Hunter | <<locked>> | 96% | 54,737 psi | 86% | 3517 fps | 98.6% |
| Ramshot TAC | <<locked>> | 82% | 54,607 psi | 86% | 3432 fps | 98.9% |
| Ramshot Wild Boar | <<locked>> | 82% | 54,636 psi | 86% | 3455 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,013 psi | 56% | 2267 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 55,347 psi | 87% | 3448 fps | 98.4% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 54,882 psi | 86% | 3547 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 54,897 psi | 86% | 3583 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 57,000 psi | 89% | 3563 fps | 99.7% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 56,130 psi | 88% | 3599 fps | 99.6% |
| Rottweil R 901 | <<locked>> | 82% | 54,505 psi | 85% | 3392 fps | 100% |
| Rottweil R 902 | <<locked>> | 86% | 54,766 psi | 86% | 3412 fps | 100% |
| Rottweil R 903 | <<locked>> | 90% | 54,447 psi | 85% | 3451 fps | 100% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 52,620 psi | 82% | 3468 fps | 96% |
| Rottweil R 907 | <<locked>> | 92% | 54,433 psi | 85% | 3425 fps | 97.1% |
| Shooters World Long Rifle | <<locked>> | 94% | 55,767 psi | 87% | 3451 fps | 98.9% |
| Shooters World Match Rifle | <<locked>> | 84% | 55,622 psi | 87% | 3445 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 56,246 psi | 88% | 3455 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 57,043 psi | 89% | 3494 fps | 98.3% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 56,420 psi | 88% | 3520 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 57,058 psi | 89% | 3474 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 54,244 psi | 85% | 3442 fps | 99.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 55,216 psi | 87% | 3346 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 56,130 psi | 88% | 3340 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 56,014 psi | 88% | 3396 fps | 98% |
| Somchem S335 | <<locked>> | 84% | 54,723 psi | 86% | 3337 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 56,768 psi | 89% | 3458 fps | 100% |
| Somchem S355 | <<locked>> | 90% | 54,578 psi | 86% | 3448 fps | 100% |
| Somchem S365 | <<locked>> | 98% | 54,375 psi | 85% | 3524 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 53,432 psi | 84% | 3445 fps | 97.1% |
| Vihtavuori N133 | <<locked>> | 84% | 55,680 psi | 87% | 3327 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 54,607 psi | 86% | 3369 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 55,608 psi | 87% | 3389 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 56,028 psi | 88% | 3419 fps | 100% |
| Vihtavuori N160 | <<locked>> | 94% | 54,418 psi | 85% | 3458 fps | 99.5% |
| Vihtavuori N530 | <<locked>> | 82% | 54,621 psi | 86% | 3415 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 57,551 psi | 90% | 3438 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 57,159 psi | 90% | 3520 fps | 99.6% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 49,530 psi | 78% | 3445 fps | 99.4% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 54,650 psi | 86% | 3425 fps | 100% |
| Winchester 748 | <<locked>> | 82% | 55,230 psi | 87% | 3471 fps | 100% |
| Winchester 760 | <<locked>> | 94% | 56,086 psi | 88% | 3537 fps | 98.1% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 40,059 psi | 63% | 3373 fps | 99.7% |
| Winchester StaBALL Match | <<locked>> | 84% | 54,114 psi | 85% | 3445 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 80% | 52,533 psi | 82% | 3304 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 45,049 psi | 71% | 3205 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 53,301 psi | 84% | 3396 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 47,311 psi | 74% | 3241 fps | 95.2% |
| Accurate 3100 | <<locked>> | 96% | 40,799 psi | 64% | 3179 fps | 95.4% |
| Accurate 4064 | <<locked>> | 80% | 42,612 psi | 67% | 3199 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 36,666 psi | 57% | 3114 fps | 95.8% |
| ADI AR 2206H | <<locked>> | 80% | 48,689 psi | 76% | 3350 fps | 99.5% |
| ADI AR 2208 | <<locked>> | 80% | 41,365 psi | 65% | 3163 fps | 97.8% |
| ADI AR 2209 | <<locked>> | 98% | 51,256 psi | 80% | 3442 fps | 95.3% |
| ADI Benchmark 8208 | <<locked>> | 80% | 50,836 psi | 80% | 3356 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 51,924 psi | 81% | 3340 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 45,121 psi | 71% | 3392 fps | 98.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 41,220 psi | 65% | 3189 fps | 99% |
| Alliant Reloder-15 | <<locked>> | 80% | 44,237 psi | 69% | 3268 fps | 98.5% |
| Alliant Reloder-16 | 57.5 gr | 84% | 36,405 psi | 57% | 3136 fps | 95.9% |
| Alliant Reloder-17 | <<locked>> | 80% | 36,013 psi | 56% | 3150 fps | 97.6% |
| Alliant Reloder-19 | <<locked>> | 98% | 50,430 psi | 79% | 3425 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 90% | 31,879 psi | 50% | 3012 fps | 95.8% |
| Alliant Reloder-26 | <<locked>> | 92% | 37,623 psi | 59% | 3238 fps | 95.8% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 48,544 psi | 76% | 3353 fps | 98.9% |
| Bofors RP3 | <<locked>> | 80% | 41,075 psi | 64% | 3189 fps | 99.1% |
| Bofors RP7 | <<locked>> | 88% | 47,703 psi | 75% | 3294 fps | 95.6% |
| Hodgdon Benchmark | <<locked>> | 80% | 52,417 psi | 82% | 3343 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 50,488 psi | 79% | 3379 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 41,800 psi | 66% | 3196 fps | 96.9% |
| Hodgdon H414 | 63.5 gr | 88% | 45,382 psi | 71% | 3323 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 88% | 48,834 psi | 77% | 3353 fps | 95.1% |
| Hodgdon H4895 | <<locked>> | 80% | 49,182 psi | 77% | 3360 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 31,256 psi | 49% | 2940 fps | 95.7% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 45,643 psi | 72% | 3323 fps | 99.7% |
| Hodgdon Superformance | <<locked>> | 88% | 45,208 psi | 71% | 3343 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,353 psi | 41% | 1988 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 47,137 psi | 74% | 3301 fps | 99.6% |
| IMR 3031 | <<locked>> | 80% | 49,226 psi | 77% | 3353 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 43,453 psi | 68% | 3209 fps | 98.5% |
| IMR 4166 Enduron | <<locked>> | 80% | 45,977 psi | 72% | 3235 fps | 95.7% |
| IMR 4350 | <<locked>> | 90% | 45,397 psi | 71% | 3258 fps | 95% |
| IMR 4451 Enduron | <<locked>> | 86% | 46,412 psi | 73% | 3268 fps | 95.8% |
| IMR 4831 | <<locked>> | 84% | 35,404 psi | 55% | 3061 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 45,353 psi | 71% | 3304 fps | 99.1% |
| IMR 8208 XBR | <<locked>> | 80% | 50,836 psi | 80% | 3356 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 48,341 psi | 76% | 3317 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 48,225 psi | 76% | 3271 fps | 99.5% |
| Lovex S062 | <<locked>> | 80% | 43,366 psi | 68% | 3209 fps | 99.5% |
| Lovex S065 | <<locked>> | 84% | 40,422 psi | 63% | 3130 fps | 95.6% |
| Lovex S070 | <<locked>> | 88% | 44,063 psi | 69% | 3235 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 47,471 psi | 74% | 3287 fps | 99.9% |
| Norma 202 | <<locked>> | 80% | 48,095 psi | 75% | 3297 fps | 100% |
| Norma 203B | <<locked>> | 80% | 43,598 psi | 68% | 3255 fps | 98.8% |
| Norma 204 | <<locked>> | 94% | 52,330 psi | 82% | 3442 fps | 95.4% |
| Norma MRP | <<locked>> | 98% | 46,876 psi | 73% | 3432 fps | 96.1% |
| Norma URP | <<locked>> | 84% | 36,941 psi | 58% | 3120 fps | 95.8% |
| Ramshot Big Game | <<locked>> | 80% | 43,801 psi | 69% | 3271 fps | 98.8% |
| Ramshot Hunter | <<locked>> | 88% | 41,437 psi | 65% | 3238 fps | 95.5% |
| Ramshot TAC | <<locked>> | 80% | 51,039 psi | 80% | 3363 fps | 98.3% |
| Ramshot Wild Boar | <<locked>> | 80% | 50,981 psi | 80% | 3389 fps | 99.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,760 psi | 42% | 2037 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 42,279 psi | 66% | 3179 fps | 95.4% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 47,558 psi | 75% | 3402 fps | 99% |
| ReloadSwiss RS 60 | 59 gr | 80% | 38,377 psi | 60% | 3232 fps | 99.8% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 36,811 psi | 58% | 3136 fps | 95.5% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 39,117 psi | 61% | 3219 fps | 95.7% |
| Rottweil R 901 | <<locked>> | 80% | 51,256 psi | 80% | 3337 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 45,092 psi | 71% | 3228 fps | 99.7% |
| Rottweil R 903 | <<locked>> | 80% | 38,580 psi | 60% | 3123 fps | 98.3% |
| Rottweil R 905 | <<locked>> | 98% | 49,095 psi | 77% | 3399 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 88% | 47,703 psi | 75% | 3294 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 84% | 40,422 psi | 63% | 3130 fps | 95.6% |
| Shooters World Match Rifle | <<locked>> | 80% | 48,341 psi | 76% | 3317 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 43,366 psi | 68% | 3209 fps | 99.5% |
| Shooters World SW4350 | <<locked>> | 88% | 44,063 psi | 69% | 3235 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 40,016 psi | 63% | 3186 fps | 98% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 49,516 psi | 78% | 3333 fps | 98.5% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 47,442 psi | 74% | 3310 fps | 99.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 48,733 psi | 76% | 3235 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 40,799 psi | 64% | 3068 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 45,818 psi | 72% | 3202 fps | 95.8% |
| Somchem S335 | <<locked>> | 80% | 48,356 psi | 76% | 3228 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 49,385 psi | 77% | 3327 fps | 99.6% |
| Somchem S355 | <<locked>> | 80% | 39,262 psi | 62% | 3130 fps | 98.3% |
| Somchem S365 | <<locked>> | 80% | 28,631 psi | 45% | 2913 fps | 95.9% |
| Somchem S385 | <<locked>> | 96% | 46,630 psi | 73% | 3310 fps | 95.4% |
| Vihtavuori N133 | <<locked>> | 80% | 49,211 psi | 77% | 3222 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 45,063 psi | 71% | 3209 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 45,585 psi | 71% | 3215 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 37,449 psi | 59% | 3054 fps | 99% |
| Vihtavuori N160 | <<locked>> | 82% | 35,868 psi | 56% | 3054 fps | 95.3% |
| Vihtavuori N530 | <<locked>> | 80% | 51,082 psi | 80% | 3353 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 43,990 psi | 69% | 3196 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 37,956 psi | 59% | 3120 fps | 95.9% |
| Vihtavuori N555 | <<locked>> | 90% | 34,896 psi | 55% | 3104 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 33,272 psi | 52% | 2956 fps | 96.9% |
| Winchester 748 | <<locked>> | 80% | 51,401 psi | 81% | 3406 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 45,382 psi | 71% | 3323 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 92% | 30,269 psi | 47% | 3038 fps | 95.7% |
| Winchester StaBALL Match | <<locked>> | 80% | 47,210 psi | 74% | 3314 fps | 99.6% |
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 116 powders for .270 Weath. Mag. loaded with the .277 | 100gr | Hornady GMX. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,619 fps; across all powders the maximum-charge window runs from 2,221 fps to 3,619 fps. Accurate 3100 gives the best case fill at 100 %, and 116 of the 116 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 56–90 %, leaving at least 10 % headroom. The 100.0 gr projectile in 0.277" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate MAGPRO, ADI AR 2209 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 60, Hodgdon H414, Alliant Reloder-16 rank at the top here: for .270 Weath. Mag. with the .277 | 100gr | Hornady GMX they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate MAGPRO, ADI AR 2213, Alliant Reloder-22 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.