Load Specifications
Load data in caliber .260 Rem. with .264 | 121gr | Lehigh Defense Match Solid 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, Alliant Reloder-17 and Alliant Power Pro 2000-MR.
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>> | 84% | 51,401 psi | 85% | 2687 fps | 100% |
| Accurate 2460 | <<locked>> | 82% | 52,837 psi | 88% | 2753 fps | 100% |
| Accurate 2495 | <<locked>> | 90% | 52,866 psi | 88% | 2753 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 51,343 psi | 85% | 2769 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 52,475 psi | 87% | 2733 fps | 95.7% |
| Accurate 4064 | <<locked>> | 92% | 52,663 psi | 87% | 2795 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 51,721 psi | 86% | 2858 fps | 99% |
| ADI AR 2206H | <<locked>> | 88% | 53,563 psi | 89% | 2825 fps | 99.7% |
| ADI AR 2208 | <<locked>> | 92% | 51,474 psi | 86% | 2772 fps | 99.2% |
| ADI Benchmark 8208 | <<locked>> | 86% | 52,881 psi | 88% | 2779 fps | 100% |
| Alliant AR-Comp | <<locked>> | 86% | 53,127 psi | 88% | 2759 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 90% | 53,142 psi | 88% | 2936 fps | 99.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 94% | 54,157 psi | 90% | 2841 fps | 100% |
| Alliant Reloder-10x | <<locked>> | 82% | 54,201 psi | 90% | 2733 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 51,706 psi | 86% | 2815 fps | 99.4% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 50,343 psi | 84% | 2864 fps | 99% |
| Alliant Reloder-17 | <<locked>> | 96% | 51,227 psi | 85% | 2904 fps | 99.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 35,810 psi | 59% | 2592 fps | 97% |
| Baschieri & Pellagri 107 | <<locked>> | 88% | 53,461 psi | 89% | 2841 fps | 99.2% |
| Bofors RP3 | <<locked>> | 92% | 51,445 psi | 85% | 2812 fps | 99.9% |
| Bofors RP7 | <<locked>> | 96% | 52,011 psi | 86% | 2772 fps | 95.9% |
| Hodgdon Benchmark | <<locked>> | 84% | 51,576 psi | 86% | 2717 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 51,953 psi | 86% | 2808 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 84% | 53,795 psi | 89% | 2904 fps | 99.6% |
| Hodgdon H322 | <<locked>> | 82% | 53,577 psi | 89% | 2776 fps | 100% |
| Hodgdon H380 | <<locked>> | 92% | 52,576 psi | 87% | 2818 fps | 98.7% |
| Hodgdon H414 | <<locked>> | 98% | 51,663 psi | 86% | 2858 fps | 96.7% |
| Hodgdon H4895 | <<locked>> | 88% | 54,041 psi | 90% | 2835 fps | 99.9% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 46,383 psi | 77% | 2743 fps | 99.4% |
| Hodgdon LEVERevolution | <<locked>> | 90% | 53,229 psi | 88% | 2867 fps | 100% |
| Hodgdon Superformance | <<locked>> | 98% | 52,591 psi | 87% | 2890 fps | 96.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,259 psi | 59% | 1716 fps | 100% |
| Hodgdon VARGET | <<locked>> | 88% | 52,083 psi | 87% | 2785 fps | 99.8% |
| IMR 3031 | <<locked>> | 88% | 53,882 psi | 90% | 2822 fps | 100% |
| IMR 4064 | <<locked>> | 92% | 54,172 psi | 90% | 2805 fps | 99.6% |
| IMR 4166 Enduron | <<locked>> | 88% | 51,227 psi | 85% | 2730 fps | 96.4% |
| IMR 4198 | <<locked>> | 82% | 54,462 psi | 90% | 2694 fps | 100% |
| IMR 4350ᴾ | <<locked>> | 100% | 51,837 psi | 86% | 2792 fps | 95.9% |
| IMR 4451 Enduron | <<locked>> | 96% | 53,722 psi | 89% | 2802 fps | 96.8% |
| IMR 4831ᴾ | <<locked>> | 100% | 48,979 psi | 81% | 2799 fps | 98.6% |
| IMR 4895 | <<locked>> | 90% | 52,997 psi | 88% | 2844 fps | 99.7% |
| IMR 8208 XBR | <<locked>> | 86% | 52,881 psi | 88% | 2779 fps | 100% |
| Lovex D073.5 | <<locked>> | 82% | 52,765 psi | 88% | 2762 fps | 100% |
| Lovex D073.6 | <<locked>> | 88% | 53,185 psi | 88% | 2805 fps | 100% |
| Lovex S060 | <<locked>> | 88% | 53,534 psi | 89% | 2753 fps | 99.7% |
| Lovex S062 | <<locked>> | 92% | 53,882 psi | 90% | 2805 fps | 100% |
| Lovex S065 | <<locked>> | 98% | 53,011 psi | 88% | 2799 fps | 98% |
| Lovex S070ᴾ | <<locked>> | 100% | 53,751 psi | 89% | 2828 fps | 97.2% |
| Norma 201 | <<locked>> | 88% | 52,373 psi | 87% | 2772 fps | 100% |
| Norma 202 | <<locked>> | 88% | 52,779 psi | 88% | 2776 fps | 100% |
| Norma 203B | <<locked>> | 92% | 54,027 psi | 90% | 2851 fps | 99.8% |
| Norma URPᴾ | <<locked>> | 100% | 51,314 psi | 85% | 2851 fps | 98.8% |
| Ramshot Big Game | <<locked>> | 90% | 51,155 psi | 85% | 2825 fps | 99.5% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 50,212 psi | 83% | 2841 fps | 97.2% |
| Ramshot TAC | <<locked>> | 86% | 53,011 psi | 88% | 2789 fps | 98.2% |
| Ramshot Wild Boar | <<locked>> | 86% | 52,562 psi | 87% | 2812 fps | 99.6% |
| Ramshot X-Terminator | <<locked>> | 84% | 53,708 psi | 89% | 2779 fps | 99.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,418 psi | 59% | 1752 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 52,489 psi | 87% | 2762 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 92% | 52,982 psi | 88% | 2799 fps | 97.4% |
| ReloadSwiss RS 52 | <<locked>> | 88% | 51,764 psi | 86% | 2877 fps | 99.4% |
| ReloadSwiss RS 60 | <<locked>> | 94% | 51,039 psi | 85% | 2910 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 51,227 psi | 85% | 2877 fps | 98.7% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 51,924 psi | 86% | 2907 fps | 98.4% |
| Rottweil R 901 | <<locked>> | 86% | 53,693 psi | 89% | 2759 fps | 100% |
| Rottweil R 902 | <<locked>> | 90% | 52,895 psi | 88% | 2769 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 50,923 psi | 85% | 2795 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 96% | 52,011 psi | 86% | 2772 fps | 95.9% |
| Shooters World Long Rifle | <<locked>> | 98% | 53,011 psi | 88% | 2799 fps | 98% |
| Shooters World Match Rifle | <<locked>> | 88% | 53,185 psi | 88% | 2805 fps | 100% |
| Shooters World Precision | <<locked>> | 92% | 53,882 psi | 90% | 2805 fps | 100% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 53,751 psi | 89% | 2828 fps | 97.2% |
| SNPE Vectan SP 11 | <<locked>> | 94% | 52,910 psi | 88% | 2861 fps | 99.7% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 51,184 psi | 85% | 2766 fps | 98.3% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 52,257 psi | 87% | 2799 fps | 99.6% |
| SNPE Vectan Tubal 3000 | <<locked>> | 88% | 54,215 psi | 90% | 2717 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 94% | 54,128 psi | 90% | 2713 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 98% | 53,548 psi | 89% | 2753 fps | 96.8% |
| Somchem S321 | <<locked>> | 84% | 54,186 psi | 90% | 2815 fps | 100% |
| Somchem S335 | <<locked>> | 88% | 53,447 psi | 89% | 2717 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 51,068 psi | 85% | 2766 fps | 99.5% |
| Somchem S355 | <<locked>> | 94% | 51,619 psi | 86% | 2795 fps | 99.8% |
| Somchem S365ᴾ | <<locked>> | 100% | 45,730 psi | 76% | 2802 fps | 99.9% |
| Vihtavuori N130 | <<locked>> | 84% | 54,056 psi | 90% | 2684 fps | 100% |
| Vihtavuori N133 | <<locked>> | 88% | 54,317 psi | 90% | 2703 fps | 100% |
| Vihtavuori N135 | <<locked>> | 90% | 52,301 psi | 87% | 2740 fps | 100% |
| Vihtavuori N140 | <<locked>> | 90% | 53,519 psi | 89% | 2756 fps | 100% |
| Vihtavuori N150 | <<locked>> | 96% | 53,127 psi | 88% | 2779 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 53,766 psi | 89% | 2848 fps | 99.1% |
| Vihtavuori N530 | <<locked>> | 86% | 53,330 psi | 89% | 2779 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 51,547 psi | 86% | 2753 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 52,707 psi | 88% | 2851 fps | 98.8% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 38,450 psi | 64% | 2671 fps | 97% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 50,981 psi | 85% | 2779 fps | 99.8% |
| Winchester 748 | <<locked>> | 86% | 52,881 psi | 88% | 2825 fps | 100% |
| Winchester 760 | <<locked>> | 98% | 51,663 psi | 86% | 2858 fps | 96.7% |
| Winchester StaBALL Match | <<locked>> | 88% | 51,909 psi | 86% | 2805 fps | 99.8% |
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% | 45,498 psi | 76% | 2598 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 49,429 psi | 82% | 2700 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 37,971 psi | 63% | 2516 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 44,730 psi | 74% | 2661 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 49,458 psi | 82% | 2687 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 35,897 psi | 60% | 2503 fps | 99.7% |
| Accurate 4350 | <<locked>> | 90% | 36,651 psi | 61% | 2582 fps | 95.7% |
| ADI AR 2206H | <<locked>> | 80% | 41,930 psi | 70% | 2618 fps | 98.2% |
| ADI AR 2208 | <<locked>> | 80% | 35,665 psi | 59% | 2467 fps | 95.8% |
| ADI Benchmark 8208 | <<locked>> | 80% | 43,961 psi | 73% | 2631 fps | 99.4% |
| Alliant AR-Comp | <<locked>> | 80% | 43,337 psi | 72% | 2618 fps | 100% |
| Alliant Power Pro 2000-MR | 36.1 gr | 80% | 37,826 psi | 63% | 2631 fps | 96.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 34,896 psi | 58% | 2487 fps | 97.4% |
| Alliant Reloder-10x | <<locked>> | 80% | 51,010 psi | 85% | 2687 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 37,710 psi | 63% | 2549 fps | 96.7% |
| Alliant Reloder-16 | <<locked>> | 90% | 37,130 psi | 62% | 2595 fps | 95.7% |
| Alliant Reloder-17 | 36.4 gr | 82% | 32,184 psi | 53% | 2497 fps | 95.7% |
| Alliant Reloder-23 | <<locked>> | 96% | 31,618 psi | 53% | 2484 fps | 95.2% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 40,683 psi | 68% | 2612 fps | 96.9% |
| Bofors RP3 | <<locked>> | 80% | 34,301 psi | 57% | 2487 fps | 97.3% |
| Bofors RP7 | <<locked>> | 94% | 48,617 psi | 81% | 2713 fps | 95.1% |
| Hodgdon Benchmark | <<locked>> | 80% | 45,571 psi | 76% | 2618 fps | 99.8% |
| Hodgdon BL-C2 | <<locked>> | 80% | 42,453 psi | 71% | 2648 fps | 99.5% |
| Hodgdon CFE223 | <<locked>> | 80% | 46,499 psi | 77% | 2782 fps | 98.7% |
| Hodgdon H322 | <<locked>> | 80% | 49,966 psi | 83% | 2726 fps | 100% |
| Hodgdon H380 | <<locked>> | 82% | 37,884 psi | 63% | 2546 fps | 95.3% |
| Hodgdon H414 | <<locked>> | 94% | 45,063 psi | 75% | 2743 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 42,250 psi | 70% | 2631 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 31,850 psi | 53% | 2434 fps | 95.7% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 38,101 psi | 63% | 2595 fps | 98.3% |
| Hodgdon Superformance | <<locked>> | 96% | 48,689 psi | 81% | 2822 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,107 psi | 43% | 1529 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 40,321 psi | 67% | 2575 fps | 98.3% |
| IMR 3031 | <<locked>> | 80% | 41,394 psi | 69% | 2628 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 37,420 psi | 62% | 2503 fps | 96.7% |
| IMR 4166 Enduron | <<locked>> | 86% | 47,921 psi | 80% | 2674 fps | 95.6% |
| IMR 4198 | <<locked>> | 80% | 51,590 psi | 86% | 2654 fps | 100% |
| IMR 4350 | <<locked>> | 98% | 48,501 psi | 81% | 2736 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 92% | 47,790 psi | 79% | 2703 fps | 95.5% |
| IMR 4831 | <<locked>> | 90% | 35,331 psi | 59% | 2533 fps | 95.2% |
| IMR 4895 | <<locked>> | 80% | 38,595 psi | 64% | 2582 fps | 97.6% |
| IMR 8208 XBR | <<locked>> | 80% | 43,961 psi | 73% | 2631 fps | 99.4% |
| Lovex D073.5 | <<locked>> | 80% | 49,342 psi | 82% | 2710 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 40,596 psi | 67% | 2598 fps | 99.8% |
| Lovex S060 | <<locked>> | 80% | 42,032 psi | 70% | 2556 fps | 98.3% |
| Lovex S062 | <<locked>> | 80% | 37,014 psi | 61% | 2503 fps | 98.3% |
| Lovex S065 | <<locked>> | 90% | 41,597 psi | 69% | 2595 fps | 95.5% |
| Lovex S070 | <<locked>> | 94% | 44,309 psi | 74% | 2667 fps | 95% |
| Norma 201 | <<locked>> | 80% | 40,901 psi | 68% | 2572 fps | 99% |
| Norma 202 | <<locked>> | 80% | 41,133 psi | 68% | 2582 fps | 100% |
| Norma 203B | <<locked>> | 80% | 37,086 psi | 62% | 2539 fps | 97.1% |
| Norma URP | <<locked>> | 90% | 37,130 psi | 62% | 2585 fps | 95.6% |
| Ramshot Big Game | <<locked>> | 80% | 36,463 psi | 61% | 2546 fps | 96.7% |
| Ramshot Hunter | <<locked>> | 96% | 43,947 psi | 73% | 2726 fps | 95.6% |
| Ramshot TAC | <<locked>> | 80% | 43,700 psi | 73% | 2628 fps | 96.3% |
| Ramshot Wild Boar | <<locked>> | 80% | 43,091 psi | 72% | 2648 fps | 98.4% |
| Ramshot X-Terminator | <<locked>> | 80% | 47,210 psi | 78% | 2671 fps | 99% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,324 psi | 44% | 1565 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 49,066 psi | 82% | 2710 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 43,787 psi | 73% | 2638 fps | 95.3% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 39,175 psi | 65% | 2648 fps | 97.1% |
| ReloadSwiss RS 60 | 35.5 gr | 80% | 32,053 psi | 53% | 2507 fps | 98.2% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 36,448 psi | 61% | 2595 fps | 95.1% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 39,653 psi | 66% | 2664 fps | 95.1% |
| Rottweil R 901 | <<locked>> | 80% | 44,976 psi | 75% | 2621 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 38,856 psi | 65% | 2523 fps | 98.6% |
| Rottweil R 903 | <<locked>> | 80% | 32,372 psi | 54% | 2431 fps | 96.4% |
| Rottweil R 907 | <<locked>> | 94% | 48,617 psi | 81% | 2713 fps | 95.1% |
| Shooters World Long Rifle | <<locked>> | 90% | 41,597 psi | 69% | 2595 fps | 95.5% |
| Shooters World Match Rifle | <<locked>> | 80% | 40,596 psi | 67% | 2598 fps | 99.8% |
| Shooters World Precision | <<locked>> | 80% | 37,014 psi | 61% | 2503 fps | 98.3% |
| Shooters World SW4350 | <<locked>> | 94% | 44,309 psi | 74% | 2667 fps | 95% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 33,446 psi | 56% | 2480 fps | 95.7% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 41,800 psi | 69% | 2598 fps | 96.4% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 40,408 psi | 67% | 2585 fps | 97.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 42,395 psi | 70% | 2533 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 35,085 psi | 58% | 2398 fps | 99.9% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 46,891 psi | 78% | 2648 fps | 95.4% |
| Somchem S321 | <<locked>> | 80% | 47,094 psi | 78% | 2703 fps | 99.8% |
| Somchem S335 | <<locked>> | 80% | 41,959 psi | 70% | 2533 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 41,466 psi | 69% | 2595 fps | 98.1% |
| Somchem S355 | <<locked>> | 80% | 33,286 psi | 55% | 2438 fps | 96.4% |
| Somchem S365 | <<locked>> | 84% | 27,427 psi | 46% | 2369 fps | 95.1% |
| Vihtavuori N130 | <<locked>> | 80% | 47,950 psi | 80% | 2598 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 42,641 psi | 71% | 2530 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 38,116 psi | 63% | 2513 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 38,943 psi | 65% | 2520 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 80% | 31,662 psi | 53% | 2382 fps | 97.3% |
| Vihtavuori N160 | <<locked>> | 88% | 36,318 psi | 60% | 2530 fps | 95.2% |
| Vihtavuori N530 | <<locked>> | 80% | 43,743 psi | 73% | 2621 fps | 99.4% |
| Vihtavuori N540 | <<locked>> | 80% | 37,449 psi | 62% | 2507 fps | 99.7% |
| Vihtavuori N550 | <<locked>> | 90% | 38,072 psi | 63% | 2585 fps | 95.6% |
| Vihtavuori N555 | <<locked>> | 96% | 33,736 psi | 56% | 2559 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 32,314 psi | 54% | 2408 fps | 95.9% |
| Winchester 748 | <<locked>> | 80% | 43,033 psi | 71% | 2664 fps | 99.7% |
| Winchester 760 | <<locked>> | 94% | 45,455 psi | 76% | 2749 fps | 95.1% |
| Winchester StaBALL Match | <<locked>> | 80% | 39,595 psi | 66% | 2589 fps | 98.3% |
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 Rem. loaded with the .264 | 121gr | Lehigh Defense Match Solid. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 2,936 fps; across all powders the maximum-charge window runs from 1,716 fps to 2,936 fps. Accurate 4350 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 (415 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 121.0 gr projectile in 0.264" calls for a 1:8.0 twist; slower twists will usually not stabilise this weight. Accurate 4350, 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. ReloadSwiss RS 60, Alliant Reloder-17, Alliant Power Pro 2000-MR rank at the top here: for .260 Rem. with the .264 | 121gr | Lehigh Defense Match Solid 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.