Load Specifications
Load data in caliber .280 Ackley Improved with .284 | 100gr | Sierra VarmintKing 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 Power Pro 2000-MR, ReloadSwiss RS 60 and Alliant Reloder-17.
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.
A valid access license is required to use the Personalized Load Calculator.
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>> | 86% | 57,087 psi | 88% | 3337 fps | 100% |
| Accurate 2460 | <<locked>> | 82% | 55,550 psi | 85% | 3353 fps | 100% |
| Accurate 2495 | <<locked>> | 90% | 55,796 psi | 86% | 3353 fps | 100% |
| Accurate 2520 | <<locked>> | 86% | 56,043 psi | 86% | 3402 fps | 100% |
| Accurate 2520 | <<locked>> | 86% | 56,043 psi | 86% | 3402 fps | 100% |
| Accurate 4064 | <<locked>> | 92% | 55,753 psi | 86% | 3399 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 55,927 psi | 86% | 3468 fps | 98.5% |
| Accurate LT-30 | <<locked>> | 82% | 58,798 psi | 90% | 3327 fps | 100% |
| ADI AR 2206H | <<locked>> | 88% | 56,405 psi | 87% | 3435 fps | 99.3% |
| ADI AR 2208 | <<locked>> | 94% | 57,392 psi | 88% | 3425 fps | 99% |
| ADI Benchmark 8208 | <<locked>> | 86% | 55,143 psi | 85% | 3379 fps | 99.7% |
| Alliant AR-Comp | <<locked>> | 86% | 55,811 psi | 86% | 3369 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 82% | 56,898 psi | 88% | 3507 fps | 99.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 90% | 56,333 psi | 87% | 3553 fps | 98.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 94% | 57,305 psi | 88% | 3451 fps | 99.8% |
| Alliant Reloder-10x | <<locked>> | 82% | 56,260 psi | 87% | 3346 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 92% | 58,001 psi | 89% | 3474 fps | 99.2% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 53,563 psi | 82% | 3468 fps | 98.4% |
| Alliant Reloder-17 | <<locked>> | 96% | 55,056 psi | 85% | 3520 fps | 99.7% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 58,566 psi | 90% | 3307 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 88% | 56,449 psi | 87% | 3438 fps | 98.7% |
| Bofors RP3 | <<locked>> | 94% | 58,276 psi | 90% | 3468 fps | 99.9% |
| Hodgdon Benchmark | <<locked>> | 86% | 57,014 psi | 88% | 3366 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 54,926 psi | 85% | 3409 fps | 99.9% |
| Hodgdon CFE223 | <<locked>> | 84% | 56,652 psi | 87% | 3517 fps | 99% |
| Hodgdon H322 | <<locked>> | 86% | 58,726 psi | 90% | 3435 fps | 100% |
| Hodgdon H380 | <<locked>> | 92% | 55,535 psi | 85% | 3415 fps | 97.9% |
| Hodgdon H414 | <<locked>> | 96% | 57,000 psi | 88% | 3488 fps | 96.2% |
| Hodgdon H4895 | <<locked>> | 88% | 56,942 psi | 88% | 3448 fps | 99.6% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 49,588 psi | 76% | 3323 fps | 98.9% |
| Hodgdon LEVERevolution | <<locked>> | 92% | 56,333 psi | 87% | 3474 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,186 psi | 54% | 2165 fps | 100% |
| Hodgdon VARGET | <<locked>> | 92% | 56,884 psi | 88% | 3425 fps | 99.6% |
| IMR 3031 | <<locked>> | 92% | 58,334 psi | 90% | 3465 fps | 100% |
| IMR 4064 | <<locked>> | 94% | 55,898 psi | 86% | 3392 fps | 99% |
| IMR 4198 | <<locked>> | 82% | 56,115 psi | 86% | 3307 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 96% | 56,724 psi | 87% | 3396 fps | 95.9% |
| IMR 4831ᴾ | <<locked>> | 100% | 46,804 psi | 72% | 3271 fps | 96.8% |
| IMR 4895 | <<locked>> | 90% | 55,825 psi | 86% | 3448 fps | 99.3% |
| IMR 8208 XBR | <<locked>> | 86% | 55,143 psi | 85% | 3379 fps | 99.7% |
| Lovex D073.5 | <<locked>> | 82% | 55,405 psi | 85% | 3360 fps | 100% |
| Lovex D073.6 | <<locked>> | 88% | 56,043 psi | 86% | 3402 fps | 100% |
| Lovex S060 | <<locked>> | 88% | 55,854 psi | 86% | 3353 fps | 99.3% |
| Lovex S062 | <<locked>> | 92% | 56,666 psi | 87% | 3409 fps | 99.9% |
| Lovex S065 | <<locked>> | 98% | 56,057 psi | 86% | 3389 fps | 97.3% |
| Lovex S070ᴾ | <<locked>> | 100% | 57,087 psi | 88% | 3425 fps | 96.4% |
| Norma 201 | <<locked>> | 90% | 58,523 psi | 90% | 3432 fps | 99.9% |
| Norma 202 | <<locked>> | 88% | 55,434 psi | 85% | 3379 fps | 100% |
| Norma 203B | <<locked>> | 92% | 57,159 psi | 88% | 3458 fps | 99.4% |
| Norma URPᴾ | <<locked>> | 100% | 54,911 psi | 85% | 3451 fps | 98.3% |
| Ramshot Big Game | <<locked>> | 92% | 58,262 psi | 90% | 3488 fps | 99.4% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 54,027 psi | 83% | 3438 fps | 96.5% |
| Ramshot TAC | <<locked>> | 86% | 55,912 psi | 86% | 3386 fps | 97.4% |
| Ramshot Wild Boar | <<locked>> | 86% | 55,259 psi | 85% | 3409 fps | 99.2% |
| Ramshot X-Terminator | <<locked>> | 84% | 56,478 psi | 87% | 3379 fps | 99.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,520 psi | 55% | 2211 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 84% | 58,291 psi | 90% | 3425 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 92% | 56,159 psi | 86% | 3392 fps | 96.6% |
| ReloadSwiss RS 52 | <<locked>> | 90% | 58,624 psi | 90% | 3553 fps | 99.2% |
| ReloadSwiss RS 60 | <<locked>> | 96% | 58,740 psi | 90% | 3596 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 55,869 psi | 86% | 3484 fps | 98.3% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 55,724 psi | 86% | 3514 fps | 97.9% |
| Rottweil R 901 | <<locked>> | 86% | 55,796 psi | 86% | 3363 fps | 100% |
| Rottweil R 902 | <<locked>> | 90% | 55,593 psi | 86% | 3373 fps | 99.8% |
| Rottweil R 903 | <<locked>> | 96% | 58,088 psi | 89% | 3458 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 98% | 56,057 psi | 86% | 3389 fps | 97.3% |
| Shooters World Match Rifle | <<locked>> | 88% | 56,043 psi | 86% | 3402 fps | 100% |
| Shooters World Precision | <<locked>> | 92% | 56,666 psi | 87% | 3409 fps | 99.9% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 57,087 psi | 88% | 3425 fps | 96.4% |
| Shooters World Tactical Rifle | <<locked>> | 82% | 57,972 psi | 89% | 3386 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 94% | 56,391 psi | 87% | 3465 fps | 99.3% |
| SNPE Vectan SP 3 | <<locked>> | 82% | 57,377 psi | 88% | 3376 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 88% | 58,102 psi | 89% | 3425 fps | 98.2% |
| SNPE Vectan SP 9 | <<locked>> | 90% | 58,407 psi | 90% | 3455 fps | 99.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 88% | 56,492 psi | 87% | 3317 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 94% | 56,942 psi | 88% | 3307 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 98% | 56,637 psi | 87% | 3333 fps | 96% |
| Somchem S321 | <<locked>> | 84% | 56,666 psi | 87% | 3415 fps | 99.9% |
| Somchem S335 | <<locked>> | 88% | 55,898 psi | 86% | 3307 fps | 100% |
| Somchem S341 | <<locked>> | 88% | 57,609 psi | 89% | 3415 fps | 99.4% |
| Somchem S355 | <<locked>> | 96% | 58,320 psi | 90% | 3458 fps | 99.7% |
| Somchem S365ᴾ | <<locked>> | 100% | 49,095 psi | 76% | 3386 fps | 99.7% |
| Unknown powder | <<locked>> | 98% | 56,043 psi | 86% | 3465 fps | 97.9% |
| Vihtavuori N130 | <<locked>> | 86% | 58,233 psi | 90% | 3320 fps | 100% |
| Vihtavuori N133 | <<locked>> | 90% | 55,738 psi | 86% | 3294 fps | 100% |
| Vihtavuori N135 | <<locked>> | 92% | 58,552 psi | 90% | 3396 fps | 100% |
| Vihtavuori N140 | <<locked>> | 92% | 58,769 psi | 90% | 3399 fps | 100% |
| Vihtavuori N150ᴾ | <<locked>> | 100% | 56,101 psi | 86% | 3376 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 56,710 psi | 87% | 3432 fps | 98.4% |
| Vihtavuori N530 | <<locked>> | 86% | 58,769 psi | 90% | 3455 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 90% | 55,042 psi | 85% | 3366 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 57,043 psi | 88% | 3484 fps | 98.4% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 41,597 psi | 64% | 3219 fps | 95.9% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 58,581 psi | 90% | 3432 fps | 99.9% |
| Winchester 748 | <<locked>> | 84% | 56,318 psi | 87% | 3442 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 57,000 psi | 88% | 3488 fps | 96.2% |
| Winchester StaBALL Match | <<locked>> | 82% | 56,275 psi | 87% | 3425 fps | 99.6% |
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% | 47,210 psi | 73% | 3173 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 51,837 psi | 80% | 3291 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 39,856 psi | 61% | 3061 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 45,542 psi | 70% | 3212 fps | 99.6% |
| Accurate 2520 | <<locked>> | 80% | 45,542 psi | 70% | 3212 fps | 99.6% |
| Accurate 4064 | <<locked>> | 80% | 37,637 psi | 58% | 3035 fps | 99.1% |
| Accurate 4350 | <<locked>> | 92% | 42,032 psi | 65% | 3186 fps | 95.2% |
| Accurate LT-30 | <<locked>> | 80% | 55,201 psi | 85% | 3271 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 43,569 psi | 67% | 3173 fps | 97.1% |
| ADI AR 2208 | <<locked>> | 82% | 39,392 psi | 61% | 3051 fps | 95% |
| ADI Benchmark 8208 | <<locked>> | 80% | 45,600 psi | 70% | 3192 fps | 98.6% |
| Alliant AR-Comp | <<locked>> | 80% | 45,658 psi | 70% | 3202 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 53,258 psi | 82% | 3442 fps | 99.3% |
| Alliant Power Pro 2000-MR | 57.7 gr | 82% | 42,409 psi | 65% | 3248 fps | 95.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 36,492 psi | 56% | 3009 fps | 95.9% |
| Alliant Reloder-10x | <<locked>> | 80% | 52,982 psi | 82% | 3291 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 39,276 psi | 60% | 3081 fps | 95.1% |
| Alliant Reloder-16 | <<locked>> | 92% | 41,495 psi | 64% | 3196 fps | 95.1% |
| Alliant Reloder-17 | 58.2 gr | 84% | 36,172 psi | 56% | 3077 fps | 95% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 54,940 psi | 85% | 3255 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 42,815 psi | 66% | 3159 fps | 95.7% |
| Bofors RP3 | <<locked>> | 80% | 36,245 psi | 56% | 3009 fps | 95.9% |
| Hodgdon Benchmark | <<locked>> | 80% | 47,398 psi | 73% | 3189 fps | 99.3% |
| Hodgdon BL-C2 | <<locked>> | 80% | 44,469 psi | 68% | 3205 fps | 98.9% |
| Hodgdon CFE223 | <<locked>> | 80% | 48,936 psi | 75% | 3366 fps | 97.8% |
| Hodgdon H322 | <<locked>> | 80% | 48,240 psi | 74% | 3255 fps | 100% |
| Hodgdon H380 | <<locked>> | 86% | 45,469 psi | 70% | 3212 fps | 95.7% |
| Hodgdon H414 | <<locked>> | 94% | 53,113 psi | 82% | 3415 fps | 95.3% |
| Hodgdon H4895 | <<locked>> | 80% | 43,947 psi | 68% | 3189 fps | 97.7% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 35,737 psi | 55% | 3002 fps | 95% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 37,507 psi | 58% | 3074 fps | 96.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,063 psi | 40% | 1939 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 39,059 psi | 60% | 3054 fps | 96.3% |
| IMR 3031 | <<locked>> | 80% | 39,566 psi | 61% | 3114 fps | 99.9% |
| IMR 4064 | <<locked>> | 82% | 38,522 psi | 59% | 3022 fps | 95% |
| IMR 4198 | <<locked>> | 80% | 52,866 psi | 81% | 3255 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 94% | 53,330 psi | 82% | 3337 fps | 95.1% |
| IMR 4831 | <<locked>> | 96% | 41,176 psi | 63% | 3146 fps | 95.1% |
| IMR 4895 | <<locked>> | 80% | 40,248 psi | 62% | 3123 fps | 96.2% |
| IMR 8208 XBR | <<locked>> | 80% | 45,600 psi | 70% | 3192 fps | 98.6% |
| Lovex D073.5 | <<locked>> | 80% | 51,750 psi | 80% | 3297 fps | 99.8% |
| Lovex D073.6 | <<locked>> | 80% | 42,627 psi | 66% | 3150 fps | 99.2% |
| Lovex S060 | <<locked>> | 80% | 43,497 psi | 67% | 3107 fps | 97.2% |
| Lovex S062 | <<locked>> | 80% | 38,595 psi | 59% | 3035 fps | 97.1% |
| Lovex S065 | <<locked>> | 92% | 46,456 psi | 71% | 3202 fps | 95% |
| Lovex S070 | <<locked>> | 98% | 53,606 psi | 83% | 3360 fps | 95.6% |
| Norma 201 | <<locked>> | 80% | 42,554 psi | 65% | 3123 fps | 98.1% |
| Norma 202 | <<locked>> | 80% | 42,830 psi | 66% | 3136 fps | 99.6% |
| Norma 203B | <<locked>> | 80% | 38,696 psi | 60% | 3071 fps | 95.6% |
| Norma URP | <<locked>> | 92% | 41,843 psi | 64% | 3182 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 80% | 38,189 psi | 59% | 3074 fps | 95.2% |
| Ramshot Hunter | <<locked>> | 98% | 50,401 psi | 78% | 3366 fps | 95.6% |
| Ramshot TAC | <<locked>> | 80% | 45,643 psi | 70% | 3179 fps | 95% |
| Ramshot Wild Boar | <<locked>> | 80% | 45,092 psi | 69% | 3205 fps | 97.4% |
| Ramshot X-Terminator | <<locked>> | 80% | 49,298 psi | 76% | 3245 fps | 98.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,440 psi | 41% | 1985 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 51,082 psi | 79% | 3301 fps | 99.9% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 52,446 psi | 81% | 3323 fps | 95.8% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 41,089 psi | 63% | 3196 fps | 95.6% |
| ReloadSwiss RS 60 | 55.5 gr | 80% | 33,721 psi | 52% | 3022 fps | 96.6% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 44,976 psi | 69% | 3274 fps | 95.8% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 45,179 psi | 70% | 3287 fps | 95% |
| Rottweil R 901 | <<locked>> | 80% | 46,383 psi | 71% | 3189 fps | 99.8% |
| Rottweil R 902 | <<locked>> | 80% | 40,582 psi | 62% | 3064 fps | 97.6% |
| Rottweil R 903 | <<locked>> | 82% | 36,303 psi | 56% | 3002 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 92% | 46,456 psi | 71% | 3202 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 42,627 psi | 66% | 3150 fps | 99.2% |
| Shooters World Precision | <<locked>> | 80% | 38,595 psi | 59% | 3035 fps | 97.1% |
| Shooters World SW4350 | <<locked>> | 98% | 53,606 psi | 82% | 3360 fps | 95.6% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 54,099 psi | 83% | 3320 fps | 99.5% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 37,507 psi | 58% | 3061 fps | 95% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 53,708 psi | 83% | 3317 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 43,874 psi | 68% | 3146 fps | 95.1% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 42,119 psi | 65% | 3130 fps | 96.7% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 43,918 psi | 68% | 3087 fps | 99.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 36,434 psi | 56% | 2917 fps | 99.3% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 52,997 psi | 82% | 3268 fps | 95.2% |
| Somchem S321 | <<locked>> | 80% | 49,487 psi | 76% | 3284 fps | 99.4% |
| Somchem S335 | <<locked>> | 80% | 43,555 psi | 67% | 3084 fps | 99.9% |
| Somchem S341 | <<locked>> | 80% | 43,627 psi | 67% | 3146 fps | 97% |
| Somchem S355 | <<locked>> | 82% | 37,130 psi | 57% | 3012 fps | 95.6% |
| Somchem S365 | <<locked>> | 88% | 32,938 psi | 51% | 2986 fps | 95.4% |
| Unknown powder | <<locked>> | 92% | 45,759 psi | 70% | 3261 fps | 95.5% |
| Vihtavuori N130 | <<locked>> | 80% | 48,573 psi | 75% | 3159 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 41,321 psi | 64% | 3031 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 39,798 psi | 61% | 3061 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 39,943 psi | 61% | 3051 fps | 99.5% |
| Vihtavuori N150 | <<locked>> | 82% | 31,560 psi | 49% | 2838 fps | 95.1% |
| Vihtavuori N160 | <<locked>> | 90% | 43,091 psi | 66% | 3166 fps | 95.4% |
| Vihtavuori N530 | <<locked>> | 80% | 48,080 psi | 74% | 3258 fps | 99.1% |
| Vihtavuori N540 | <<locked>> | 80% | 39,885 psi | 61% | 3068 fps | 99.2% |
| Vihtavuori N550 | <<locked>> | 90% | 43,627 psi | 67% | 3215 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 98% | 38,841 psi | 60% | 3153 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 36,318 psi | 56% | 2969 fps | 95.5% |
| Winchester 748 | <<locked>> | 80% | 49,008 psi | 75% | 3310 fps | 99.6% |
| Winchester 760 | <<locked>> | 94% | 53,113 psi | 82% | 3415 fps | 95.3% |
| Winchester StaBALL Match | <<locked>> | 80% | 52,286 psi | 80% | 3353 fps | 99.2% |
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 110 powders for .280 Ackley Improved loaded with the .284 | 100gr | Sierra VarmintKing. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,596 fps; across all powders the maximum-charge window runs from 2,165 fps to 3,596 fps. Accurate 3100 gives the best case fill at 100 %, and 110 of the 110 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (448 MPa), the top charges use 53–90 %, leaving at least 10 % headroom. The 100.0 gr projectile in 0.284" calls for a 1:15.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate 4350, Alliant Reloder-16 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 Power Pro 2000-MR, ReloadSwiss RS 60, Alliant Reloder-17 rank at the top here: for .280 Ackley Improved with the .284 | 100gr | Sierra VarmintKing they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 3100, Alliant Reloder-26, Hodgdon H4350 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.