Load Specifications
Load data in caliber .260 Rem. with .263 | 139gr | Prvi Partizan SP BT bullet and 98 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 70, Alliant Reloder-16 and Hodgdon Superformance.
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 2495 | <<locked>> | 84% | 51,837 psi | 86% | 2562 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 53,490 psi | 89% | 2612 fps | 97.9% |
| Accurate 3100ᴾ | <<locked>> | 100% | 45,614 psi | 76% | 2585 fps | 98.2% |
| Accurate 4064 | <<locked>> | 86% | 51,793 psi | 86% | 2608 fps | 100% |
| Accurate 4350 | <<locked>> | 94% | 51,445 psi | 85% | 2694 fps | 99.8% |
| ADI AR 2206H | <<locked>> | 82% | 51,764 psi | 86% | 2635 fps | 100% |
| ADI AR 2208 | <<locked>> | 88% | 52,721 psi | 88% | 2638 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 52,924 psi | 88% | 2726 fps | 97.1% |
| ADI Benchmark 8208 | <<locked>> | 82% | 53,954 psi | 90% | 2631 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 84% | 51,082 psi | 85% | 2743 fps | 100% |
| Alliant Power Pro Varmintᴾ | <<locked>> | 100% | 52,881 psi | 88% | 2726 fps | 97.2% |
| Alliant Power Pro Varmintᴾ | <<locked>> | 100% | 52,881 psi | 88% | 2726 fps | 97.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 88% | 52,968 psi | 88% | 2657 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 86% | 53,534 psi | 89% | 2680 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 96% | 52,721 psi | 88% | 2749 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 92% | 53,606 psi | 89% | 2776 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 52,098 psi | 87% | 2717 fps | 97.1% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 43,004 psi | 71% | 2608 fps | 99.9% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 37,782 psi | 63% | 2516 fps | 96.8% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 48,486 psi | 81% | 2776 fps | 99.7% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 51,387 psi | 85% | 2648 fps | 99.9% |
| Bofors RP3 | <<locked>> | 88% | 53,650 psi | 89% | 2674 fps | 100% |
| Bofors RP7 | <<locked>> | 92% | 53,534 psi | 89% | 2654 fps | 98.2% |
| Hodgdon BL-C2 | <<locked>> | 82% | 53,534 psi | 89% | 2664 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 54,259 psi | 90% | 2687 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 94% | 54,099 psi | 90% | 2743 fps | 98.8% |
| Hodgdon H4350 | <<locked>> | 90% | 51,314 psi | 85% | 2654 fps | 97.2% |
| Hodgdon H4895 | <<locked>> | 82% | 52,272 psi | 87% | 2641 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 98% | 52,692 psi | 88% | 2677 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 51,619 psi | 86% | 2674 fps | 100% |
| Hodgdon Superformance | <<locked>> | 92% | 50,676 psi | 84% | 2723 fps | 98% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,969 psi | 60% | 1631 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 53,040 psi | 88% | 2641 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 52,257 psi | 87% | 2618 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 52,069 psi | 87% | 2618 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 84% | 51,706 psi | 86% | 2598 fps | 98.3% |
| IMR 4350 | <<locked>> | 96% | 53,925 psi | 90% | 2680 fps | 98.3% |
| IMR 4451 Enduron | <<locked>> | 90% | 52,083 psi | 87% | 2631 fps | 98.3% |
| IMR 4831 | <<locked>> | 96% | 52,025 psi | 86% | 2687 fps | 99.9% |
| IMR 4895 | <<locked>> | 84% | 51,488 psi | 86% | 2657 fps | 100% |
| IMR 8208 XBR | <<locked>> | 82% | 53,954 psi | 90% | 2631 fps | 100% |
| Lovex D073.6 | <<locked>> | 82% | 51,503 psi | 86% | 2608 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 54,418 psi | 90% | 2612 fps | 100% |
| Lovex S062 | <<locked>> | 86% | 52,156 psi | 87% | 2615 fps | 100% |
| Lovex S065 | <<locked>> | 92% | 51,474 psi | 86% | 2625 fps | 99.2% |
| Lovex S070 | <<locked>> | 94% | 52,634 psi | 87% | 2664 fps | 98.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 37,985 psi | 63% | 2448 fps | 96.3% |
| Norma 201 | <<locked>> | 84% | 53,925 psi | 90% | 2631 fps | 100% |
| Norma 202 | <<locked>> | 82% | 51,126 psi | 85% | 2582 fps | 100% |
| Norma 203B | <<locked>> | 86% | 52,794 psi | 88% | 2667 fps | 100% |
| Norma 204 | <<locked>> | 96% | 54,317 psi | 90% | 2726 fps | 97.3% |
| Norma MRPᴾ | <<locked>> | 100% | 48,153 psi | 80% | 2733 fps | 97.8% |
| Norma URP | <<locked>> | 96% | 53,896 psi | 90% | 2730 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 86% | 53,214 psi | 88% | 2690 fps | 100% |
| Ramshot Hunter | <<locked>> | 96% | 52,765 psi | 88% | 2730 fps | 99.2% |
| Ramshot TAC | <<locked>> | 82% | 53,766 psi | 89% | 2651 fps | 99.5% |
| Ramshot Wild Boar | <<locked>> | 82% | 53,838 psi | 89% | 2671 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,564 psi | 61% | 1670 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 54,288 psi | 90% | 2671 fps | 99.1% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 53,969 psi | 90% | 2740 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 90% | 53,403 psi | 89% | 2772 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 94% | 51,126 psi | 85% | 2713 fps | 99.7% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 53,969 psi | 90% | 2795 fps | 99.9% |
| Rottweil R 902 | <<locked>> | 86% | 54,433 psi | 90% | 2628 fps | 100% |
| Rottweil R 903 | <<locked>> | 90% | 53,505 psi | 89% | 2667 fps | 100% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 50,763 psi | 84% | 2697 fps | 97% |
| Rottweil R 907 | <<locked>> | 92% | 53,534 psi | 89% | 2654 fps | 98.2% |
| Shooters World Long Rifle | <<locked>> | 92% | 51,474 psi | 86% | 2625 fps | 99.2% |
| Shooters World Match Rifle | <<locked>> | 82% | 51,503 psi | 86% | 2608 fps | 100% |
| Shooters World Precision | <<locked>> | 86% | 52,156 psi | 87% | 2615 fps | 100% |
| Shooters World SW4350 | <<locked>> | 94% | 52,634 psi | 87% | 2664 fps | 98.7% |
| SNPE Vectan SP 11 | <<locked>> | 88% | 51,547 psi | 86% | 2674 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 82% | 52,388 psi | 87% | 2631 fps | 99.6% |
| SNPE Vectan SP 9 | <<locked>> | 84% | 53,417 psi | 89% | 2654 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 51,750 psi | 86% | 2520 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 88% | 52,098 psi | 87% | 2523 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 51,358 psi | 85% | 2579 fps | 98.3% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 50,285 psi | 84% | 2694 fps | 96.9% |
| Somchem S335 | <<locked>> | 82% | 51,387 psi | 85% | 2523 fps | 100% |
| Somchem S341 | <<locked>> | 82% | 52,315 psi | 87% | 2625 fps | 100% |
| Somchem S355 | <<locked>> | 90% | 53,867 psi | 89% | 2667 fps | 100% |
| Somchem S365 | <<locked>> | 98% | 52,547 psi | 87% | 2736 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 51,808 psi | 86% | 2680 fps | 97.9% |
| Vihtavuori N133 | <<locked>> | 82% | 52,170 psi | 87% | 2507 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 54,404 psi | 90% | 2589 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 51,692 psi | 86% | 2566 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 51,634 psi | 86% | 2595 fps | 100% |
| Vihtavuori N160 | <<locked>> | 94% | 52,895 psi | 88% | 2677 fps | 99.8% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 44,570 psi | 74% | 2549 fps | 95.9% |
| Vihtavuori N530 | <<locked>> | 82% | 54,346 psi | 90% | 2631 fps | 100% |
| Vihtavuori N540 | <<locked>> | 86% | 53,040 psi | 88% | 2605 fps | 100% |
| Vihtavuori N550 | <<locked>> | 94% | 51,924 psi | 86% | 2684 fps | 99.7% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 47,790 psi | 79% | 2680 fps | 99.8% |
| Winchester 6.5 StaBALL | <<locked>> | 94% | 52,707 psi | 88% | 2654 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 50,691 psi | 84% | 2690 fps | 98.3% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 38,551 psi | 64% | 2638 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 84% | 53,287 psi | 89% | 2661 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 48,443 psi | 80% | 2618 fps | 96.1% |
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 2495 | <<locked>> | 80% | 45,382 psi | 75% | 2470 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 43,947 psi | 73% | 2457 fps | 96% |
| Accurate 3100 | <<locked>> | 92% | 34,650 psi | 58% | 2375 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 42,931 psi | 71% | 2474 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 31,923 psi | 53% | 2326 fps | 96.1% |
| ADI AR 2206H | <<locked>> | 80% | 48,573 psi | 81% | 2585 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 41,162 psi | 68% | 2444 fps | 99% |
| ADI AR 2209 | <<locked>> | 96% | 46,775 psi | 78% | 2621 fps | 95.7% |
| ADI Benchmark 8208 | <<locked>> | 80% | 50,618 psi | 84% | 2582 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 44,483 psi | 74% | 2631 fps | 99.5% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 46,485 psi | 77% | 2618 fps | 95.7% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 46,485 psi | 77% | 2618 fps | 95.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 41,234 psi | 69% | 2467 fps | 99.8% |
| Alliant Reloder-15 | <<locked>> | 80% | 44,222 psi | 73% | 2530 fps | 99.5% |
| Alliant Reloder-16 | 34.7 gr | 80% | 32,097 psi | 53% | 2339 fps | 96.3% |
| Alliant Reloder-17 | <<locked>> | 80% | 35,636 psi | 59% | 2451 fps | 99% |
| Alliant Reloder-19 | <<locked>> | 96% | 45,861 psi | 76% | 2612 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 84% | 26,368 psi | 44% | 2208 fps | 95.1% |
| Alliant Reloder-25 | <<locked>> | 98% | 35,752 psi | 59% | 2467 fps | 95.9% |
| Alliant Reloder-26 | <<locked>> | 88% | 31,923 psi | 53% | 2421 fps | 95.3% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 47,921 psi | 80% | 2595 fps | 99.6% |
| Bofors RP3 | <<locked>> | 80% | 41,205 psi | 68% | 2477 fps | 99.8% |
| Bofors RP7 | <<locked>> | 84% | 41,785 psi | 69% | 2451 fps | 95.6% |
| Hodgdon BL-C2 | <<locked>> | 80% | 49,835 psi | 83% | 2608 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 41,887 psi | 70% | 2484 fps | 98.4% |
| Hodgdon H414 | <<locked>> | 84% | 38,783 psi | 64% | 2474 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 84% | 42,409 psi | 70% | 2500 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 49,052 psi | 81% | 2592 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 29,428 psi | 49% | 2241 fps | 97% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 45,324 psi | 75% | 2575 fps | 100% |
| Hodgdon Superformance | 42.4 gr | 86% | 40,857 psi | 68% | 2543 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,832 psi | 45% | 1457 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 47,021 psi | 78% | 2549 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 49,211 psi | 82% | 2575 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 43,207 psi | 72% | 2474 fps | 99.4% |
| IMR 4166 Enduron | <<locked>> | 80% | 45,629 psi | 76% | 2497 fps | 97.2% |
| IMR 4350 | <<locked>> | 88% | 41,887 psi | 70% | 2477 fps | 95.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 38,319 psi | 64% | 2382 fps | 95% |
| IMR 4831 | <<locked>> | 80% | 31,082 psi | 52% | 2290 fps | 95.8% |
| IMR 4895 | <<locked>> | 80% | 45,281 psi | 75% | 2556 fps | 99.8% |
| IMR 8208 XBR | <<locked>> | 80% | 50,618 psi | 84% | 2582 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 48,269 psi | 80% | 2562 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 48,022 psi | 80% | 2516 fps | 99.9% |
| Lovex S062 | <<locked>> | 80% | 43,366 psi | 72% | 2477 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 35,708 psi | 59% | 2333 fps | 95.9% |
| Lovex S070 | <<locked>> | 84% | 38,580 psi | 64% | 2415 fps | 95.6% |
| Lovex S071 | <<locked>> | 98% | 35,447 psi | 59% | 2395 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 47,500 psi | 79% | 2533 fps | 100% |
| Norma 202 | <<locked>> | 80% | 47,950 psi | 80% | 2536 fps | 100% |
| Norma 203B | <<locked>> | 80% | 43,569 psi | 72% | 2516 fps | 99.7% |
| Norma 204 | <<locked>> | 92% | 47,630 psi | 79% | 2618 fps | 95.8% |
| Norma MRP | <<locked>> | 94% | 39,305 psi | 65% | 2559 fps | 95.3% |
| Norma URP | <<locked>> | 80% | 32,169 psi | 53% | 2326 fps | 96% |
| Ramshot Big Game | <<locked>> | 80% | 43,265 psi | 72% | 2533 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 84% | 35,723 psi | 59% | 2415 fps | 95.4% |
| Ramshot TAC | <<locked>> | 80% | 50,575 psi | 84% | 2602 fps | 99.2% |
| Ramshot Wild Boar | <<locked>> | 80% | 50,198 psi | 83% | 2615 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,166 psi | 45% | 1490 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 41,945 psi | 70% | 2464 fps | 96.9% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 46,847 psi | 78% | 2631 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 37,927 psi | 63% | 2510 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 31,604 psi | 53% | 2339 fps | 95.5% |
| ReloadSwiss RS 70 | 38.9 gr | 82% | 33,678 psi | 56% | 2398 fps | 95.5% |
| Rottweil R 902 | <<locked>> | 80% | 45,237 psi | 75% | 2490 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 38,711 psi | 64% | 2425 fps | 99.5% |
| Rottweil R 905 | <<locked>> | 96% | 44,715 psi | 74% | 2595 fps | 95.6% |
| Rottweil R 907 | <<locked>> | 84% | 41,785 psi | 69% | 2451 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 35,708 psi | 59% | 2333 fps | 95.9% |
| Shooters World Match Rifle | <<locked>> | 80% | 48,269 psi | 80% | 2562 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 43,366 psi | 72% | 2477 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 38,580 psi | 64% | 2415 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 39,508 psi | 66% | 2467 fps | 99.1% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 49,139 psi | 82% | 2582 fps | 99.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 46,789 psi | 78% | 2552 fps | 99.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 48,820 psi | 81% | 2480 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 40,901 psi | 68% | 2359 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 37,376 psi | 62% | 2333 fps | 95% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 44,295 psi | 74% | 2589 fps | 95.4% |
| Somchem S335 | <<locked>> | 80% | 48,269 psi | 80% | 2477 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 48,776 psi | 81% | 2572 fps | 99.9% |
| Somchem S355 | <<locked>> | 80% | 39,334 psi | 65% | 2425 fps | 99.4% |
| Somchem S365 | <<locked>> | 80% | 28,877 psi | 48% | 2283 fps | 98.2% |
| Somchem S385 | <<locked>> | 92% | 39,929 psi | 66% | 2474 fps | 95.1% |
| Vihtavuori N133 | <<locked>> | 80% | 49,226 psi | 82% | 2467 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 45,237 psi | 75% | 2464 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 45,455 psi | 76% | 2474 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 37,463 psi | 62% | 2365 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 80% | 33,533 psi | 56% | 2326 fps | 96.5% |
| Vihtavuori N165 | <<locked>> | 98% | 41,756 psi | 69% | 2500 fps | 95.1% |
| Vihtavuori N530 | <<locked>> | 80% | 50,923 psi | 85% | 2582 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 43,918 psi | 73% | 2470 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 33,112 psi | 55% | 2329 fps | 96.1% |
| Vihtavuori N555 | <<locked>> | 84% | 28,253 psi | 47% | 2274 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 33,069 psi | 55% | 2303 fps | 98.4% |
| Winchester 760 | <<locked>> | 84% | 39,073 psi | 65% | 2480 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 88% | 26,237 psi | 44% | 2277 fps | 95.5% |
| Winchester StaBALL Match | <<locked>> | 80% | 46,586 psi | 77% | 2562 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 45,281 psi | 75% | 2566 fps | 95.3% |
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 98 powders for .260 Rem. loaded with the .263 | 139gr | Prvi Partizan SP BT. ReloadSwiss RS 70 delivers the highest muzzle velocity at 2,795 fps; across all powders the maximum-charge window runs from 1,631 fps to 2,795 fps. Accurate 3100 gives the best case fill at 100 %, and 98 of the 98 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (415 MPa), the top charges use 60–90 %, leaving at least 10 % headroom. The 139.0 gr projectile in 0.263" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, Alliant Power Pro Varmint 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 70, Alliant Reloder-16, Hodgdon Superformance rank at the top here: for .260 Rem. with the .263 | 139gr | Prvi Partizan SP BT 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.