Load Specifications
Load data in caliber .260 Ackley Improved with .264 | 123gr | Hornady ELD Match 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, Hodgdon Superformance 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 2015 | <<locked>> | 84% | 55,390 psi | 89% | 2743 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 54,085 psi | 87% | 2769 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 56,115 psi | 90% | 2838 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 53,519 psi | 86% | 2769 fps | 96.8% |
| Accurate 3100ᴾ | <<locked>> | 100% | 41,336 psi | 66% | 2661 fps | 95.9% |
| Accurate 4064 | <<locked>> | 90% | 54,114 psi | 87% | 2815 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 54,099 psi | 87% | 2904 fps | 99.6% |
| ADI AR 2206H | <<locked>> | 86% | 54,592 psi | 88% | 2848 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 55,564 psi | 89% | 2848 fps | 99.8% |
| ADI Benchmark 8208 | <<locked>> | 84% | 53,621 psi | 86% | 2799 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 54,650 psi | 88% | 2776 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 54,085 psi | 87% | 2963 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 55,811 psi | 89% | 2871 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 56,159 psi | 90% | 2890 fps | 99.9% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 55,158 psi | 88% | 2956 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 94% | 52,692 psi | 84% | 2936 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 39,523 psi | 63% | 2690 fps | 98.8% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 44,179 psi | 71% | 2851 fps | 98.1% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 54,433 psi | 87% | 2864 fps | 99.7% |
| Bofors RP3 | <<locked>> | 92% | 56,376 psi | 90% | 2887 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 53,098 psi | 85% | 2805 fps | 97% |
| Hodgdon Benchmark | <<locked>> | 84% | 55,230 psi | 89% | 2779 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 52,968 psi | 85% | 2828 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 55,027 psi | 88% | 2927 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 90% | 53,679 psi | 86% | 2844 fps | 99.3% |
| Hodgdon H414 | <<locked>> | 96% | 53,214 psi | 85% | 2894 fps | 97.7% |
| Hodgdon H4350 | <<locked>> | 94% | 53,954 psi | 87% | 2858 fps | 96.5% |
| Hodgdon H4895 | <<locked>> | 86% | 55,158 psi | 88% | 2858 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 51,445 psi | 82% | 2831 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 54,578 psi | 88% | 2890 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 53,780 psi | 86% | 2930 fps | 97.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,462 psi | 57% | 1736 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 53,040 psi | 85% | 2808 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 55,230 psi | 89% | 2841 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 54,998 psi | 88% | 2828 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 88% | 55,071 psi | 88% | 2808 fps | 97.8% |
| IMR 4350 | <<locked>> | 98% | 53,055 psi | 85% | 2825 fps | 97% |
| IMR 4451 Enduron | <<locked>> | 94% | 54,679 psi | 88% | 2831 fps | 97.7% |
| IMR 4831ᴾ | <<locked>> | 100% | 54,549 psi | 87% | 2890 fps | 99.7% |
| IMR 4895 | <<locked>> | 88% | 54,070 psi | 87% | 2867 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 53,621 psi | 86% | 2799 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 54,418 psi | 87% | 2825 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 54,012 psi | 87% | 2772 fps | 99.9% |
| Lovex S062 | <<locked>> | 90% | 54,882 psi | 88% | 2825 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 54,172 psi | 87% | 2828 fps | 98.8% |
| Lovex S070 | <<locked>> | 98% | 55,172 psi | 88% | 2864 fps | 98.1% |
| Norma 201 | <<locked>> | 86% | 53,577 psi | 86% | 2795 fps | 100% |
| Norma 202 | <<locked>> | 86% | 54,012 psi | 87% | 2795 fps | 100% |
| Norma 203B | <<locked>> | 90% | 55,332 psi | 89% | 2877 fps | 100% |
| Norma 204 | <<locked>> | 98% | 53,606 psi | 86% | 2874 fps | 95.8% |
| Norma URP | <<locked>> | 98% | 53,069 psi | 85% | 2887 fps | 99.5% |
| Ramshot Big Game | <<locked>> | 90% | 56,086 psi | 90% | 2907 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 55,550 psi | 89% | 2940 fps | 98.8% |
| Ramshot TAC | <<locked>> | 84% | 53,867 psi | 86% | 2815 fps | 98.9% |
| Ramshot Wild Boar | <<locked>> | 84% | 53,403 psi | 86% | 2835 fps | 99.9% |
| Ramshot X-Terminator | <<locked>> | 82% | 54,404 psi | 87% | 2799 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,955 psi | 58% | 1778 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 56,434 psi | 90% | 2825 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 54,099 psi | 87% | 2828 fps | 98.2% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 53,171 psi | 85% | 2904 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 94% | 56,115 psi | 90% | 2992 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 53,577 psi | 86% | 2920 fps | 99.4% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 53,345 psi | 86% | 2946 fps | 99.3% |
| Rottweil R 901 | <<locked>> | 84% | 54,505 psi | 87% | 2776 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 53,969 psi | 87% | 2795 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 56,231 psi | 90% | 2877 fps | 100% |
| Rottweil R 907 | <<locked>> | 94% | 53,098 psi | 85% | 2805 fps | 97% |
| Shooters World Long Rifle | <<locked>> | 96% | 54,172 psi | 87% | 2828 fps | 98.8% |
| Shooters World Match Rifle | <<locked>> | 86% | 54,418 psi | 87% | 2825 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 54,882 psi | 88% | 2825 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 55,172 psi | 88% | 2864 fps | 98.1% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 54,302 psi | 87% | 2887 fps | 99.9% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 56,101 psi | 90% | 2851 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 53,084 psi | 85% | 2818 fps | 99.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 54,955 psi | 88% | 2733 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 55,201 psi | 89% | 2733 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 54,665 psi | 88% | 2782 fps | 97.7% |
| Somchem S321 | <<locked>> | 82% | 54,650 psi | 88% | 2828 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 54,462 psi | 87% | 2733 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 55,550 psi | 89% | 2841 fps | 100% |
| Somchem S355 | <<locked>> | 94% | 56,362 psi | 90% | 2871 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 50,807 psi | 81% | 2887 fps | 100% |
| Vihtavuori N130 | <<locked>> | 82% | 54,781 psi | 88% | 2697 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 55,201 psi | 89% | 2720 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 53,505 psi | 86% | 2756 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 54,520 psi | 87% | 2776 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 54,462 psi | 87% | 2805 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 55,709 psi | 89% | 2884 fps | 99.6% |
| Vihtavuori N530 | <<locked>> | 84% | 53,998 psi | 87% | 2795 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 55,999 psi | 90% | 2818 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 54,447 psi | 87% | 2887 fps | 99.5% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 43,323 psi | 69% | 2769 fps | 98.7% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 56,086 psi | 90% | 2864 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 54,070 psi | 87% | 2848 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 53,214 psi | 85% | 2894 fps | 97.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 35,476 psi | 57% | 2694 fps | 98.7% |
| Winchester StaBALL Match | <<locked>> | 86% | 52,736 psi | 85% | 2825 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% | 49,124 psi | 79% | 2654 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 41,858 psi | 67% | 2582 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 49,008 psi | 79% | 2736 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 46,963 psi | 75% | 2661 fps | 95.3% |
| Accurate 3100 | <<locked>> | 98% | 38,595 psi | 62% | 2605 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 39,566 psi | 63% | 2579 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 33,214 psi | 53% | 2503 fps | 95.1% |
| ADI AR 2206H | <<locked>> | 80% | 45,324 psi | 73% | 2694 fps | 99.3% |
| ADI AR 2208 | <<locked>> | 80% | 38,435 psi | 62% | 2539 fps | 97.4% |
| ADI Benchmark 8208 | <<locked>> | 80% | 47,355 psi | 76% | 2697 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 80% | 47,761 psi | 77% | 2680 fps | 100% |
| Alliant Power Pro 2000-MR | 38.8 gr | 80% | 41,278 psi | 66% | 2723 fps | 98.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 38,189 psi | 61% | 2562 fps | 98.7% |
| Alliant Reloder-15 | <<locked>> | 80% | 40,988 psi | 66% | 2628 fps | 98.2% |
| Alliant Reloder-16 | <<locked>> | 84% | 33,591 psi | 54% | 2516 fps | 95.2% |
| Alliant Reloder-17 | <<locked>> | 80% | 33,025 psi | 53% | 2533 fps | 96.9% |
| Alliant Reloder-23 | <<locked>> | 92% | 30,806 psi | 49% | 2470 fps | 95.8% |
| Alliant Reloder-26 | <<locked>> | 94% | 35,911 psi | 58% | 2661 fps | 95.3% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 44,309 psi | 71% | 2690 fps | 98.4% |
| Bofors RP3 | <<locked>> | 80% | 37,898 psi | 61% | 2569 fps | 98.8% |
| Bofors RP7 | <<locked>> | 90% | 46,876 psi | 75% | 2697 fps | 95.6% |
| Hodgdon Benchmark | <<locked>> | 80% | 48,936 psi | 78% | 2684 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 46,369 psi | 74% | 2723 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 51,242 psi | 82% | 2867 fps | 99.7% |
| Hodgdon H380 | <<locked>> | 80% | 38,711 psi | 62% | 2572 fps | 96.4% |
| Hodgdon H414 | <<locked>> | 90% | 43,642 psi | 70% | 2723 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 90% | 47,601 psi | 76% | 2749 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 45,730 psi | 73% | 2703 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 29,008 psi | 47% | 2365 fps | 95.2% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 41,655 psi | 67% | 2674 fps | 99.4% |
| Hodgdon Superformance | 46.4 gr | 92% | 46,673 psi | 75% | 2805 fps | 95.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,585 psi | 43% | 1555 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 43,918 psi | 70% | 2654 fps | 99.4% |
| IMR 3031 | <<locked>> | 80% | 45,571 psi | 73% | 2697 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 40,364 psi | 65% | 2572 fps | 98.1% |
| IMR 4166 Enduron | <<locked>> | 80% | 42,786 psi | 69% | 2592 fps | 95.1% |
| IMR 4350 | <<locked>> | 94% | 46,876 psi | 75% | 2720 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 86% | 42,815 psi | 69% | 2621 fps | 95% |
| IMR 4831 | <<locked>> | 86% | 34,606 psi | 55% | 2520 fps | 95.8% |
| IMR 4895 | <<locked>> | 80% | 42,003 psi | 67% | 2657 fps | 98.9% |
| IMR 8208 XBR | <<locked>> | 80% | 47,355 psi | 76% | 2697 fps | 99.9% |
| Lovex D073.6 | <<locked>> | 80% | 44,498 psi | 71% | 2671 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 45,223 psi | 73% | 2628 fps | 99.3% |
| Lovex S062 | <<locked>> | 80% | 40,364 psi | 65% | 2579 fps | 99.4% |
| Lovex S065 | <<locked>> | 84% | 37,623 psi | 60% | 2523 fps | 95.1% |
| Lovex S070 | <<locked>> | 90% | 42,989 psi | 69% | 2651 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 44,367 psi | 71% | 2644 fps | 99.8% |
| Norma 202 | <<locked>> | 80% | 44,672 psi | 72% | 2651 fps | 100% |
| Norma 203B | <<locked>> | 80% | 40,379 psi | 65% | 2615 fps | 98.5% |
| Norma 204 | <<locked>> | 96% | 50,270 psi | 81% | 2818 fps | 95% |
| Norma URP | <<locked>> | 84% | 33,663 psi | 54% | 2507 fps | 95.1% |
| Ramshot Big Game | <<locked>> | 80% | 40,016 psi | 64% | 2631 fps | 98.3% |
| Ramshot Hunter | <<locked>> | 90% | 40,016 psi | 64% | 2657 fps | 95.3% |
| Ramshot TAC | <<locked>> | 80% | 47,123 psi | 76% | 2703 fps | 97.8% |
| Ramshot Wild Boar | <<locked>> | 80% | 46,862 psi | 75% | 2726 fps | 99.4% |
| Ramshot X-Terminator | <<locked>> | 80% | 50,894 psi | 82% | 2743 fps | 99.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,832 psi | 43% | 1588 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 52,997 psi | 85% | 2779 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 41,698 psi | 67% | 2608 fps | 95.5% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 43,250 psi | 69% | 2733 fps | 98.6% |
| ReloadSwiss RS 60 | 38.2 gr | 80% | 35,128 psi | 56% | 2598 fps | 99.5% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 35,418 psi | 57% | 2575 fps | 95.5% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 37,869 psi | 61% | 2641 fps | 95.5% |
| Rottweil R 901 | <<locked>> | 80% | 48,457 psi | 78% | 2684 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,264 psi | 68% | 2595 fps | 99.6% |
| Rottweil R 903 | <<locked>> | 80% | 35,636 psi | 57% | 2513 fps | 98% |
| Rottweil R 907 | <<locked>> | 90% | 46,876 psi | 75% | 2697 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 84% | 37,623 psi | 60% | 2523 fps | 95.1% |
| Shooters World Match Rifle | <<locked>> | 80% | 44,498 psi | 71% | 2671 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 40,364 psi | 65% | 2579 fps | 99.4% |
| Shooters World SW4350 | <<locked>> | 90% | 42,989 psi | 69% | 2651 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 36,622 psi | 59% | 2562 fps | 97.5% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 45,484 psi | 73% | 2677 fps | 97.9% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 43,816 psi | 70% | 2661 fps | 99.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 45,629 psi | 73% | 2595 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,014 psi | 61% | 2461 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 44,773 psi | 72% | 2621 fps | 95.7% |
| Somchem S321 | <<locked>> | 80% | 51,053 psi | 82% | 2776 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 45,266 psi | 73% | 2595 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 45,121 psi | 72% | 2674 fps | 99.2% |
| Somchem S355 | <<locked>> | 80% | 36,448 psi | 58% | 2520 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 26,469 psi | 42% | 2346 fps | 95.5% |
| Vihtavuori N130 | <<locked>> | 80% | 51,459 psi | 83% | 2651 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 45,948 psi | 74% | 2585 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 41,713 psi | 67% | 2575 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 42,308 psi | 68% | 2585 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 34,664 psi | 56% | 2457 fps | 98.7% |
| Vihtavuori N160 | <<locked>> | 84% | 35,114 psi | 56% | 2510 fps | 95.6% |
| Vihtavuori N530 | <<locked>> | 80% | 47,500 psi | 76% | 2694 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 80% | 40,814 psi | 65% | 2575 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 34,505 psi | 55% | 2507 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 90% | 31,125 psi | 50% | 2493 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 30,589 psi | 49% | 2375 fps | 96.1% |
| Winchester 748 | <<locked>> | 80% | 47,253 psi | 76% | 2740 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 43,642 psi | 70% | 2723 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 94% | 29,080 psi | 47% | 2490 fps | 95.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 43,381 psi | 70% | 2667 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 .260 Ackley Improved loaded with the .264 | 123gr | Hornady ELD Match. ReloadSwiss RS 60 delivers the highest muzzle velocity at 2,992 fps; across all powders the maximum-charge window runs from 1,736 fps to 2,992 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 123.0 gr projectile in 0.264" calls for a 1:10.0 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 Power Pro 2000-MR, Hodgdon Superformance, ReloadSwiss RS 60 rank at the top here: for .260 Ackley Improved with the .264 | 123gr | Hornady ELD Match 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.