Load Specifications
Bullet Manufacturer:Winchester
Bullet Weight:120 gr
Bullet Diameter:0.257"
Bullet Length:<<locked>>
Caliber:.25 WSSM load data
Case Length (l3):1.67"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:54.3 Grains of Water
Primer Size:Large Rifle (LR)
Barrel Length:24"
Max. allowed Pressure:63,817 psi
Recommended Twist Rate:1:12.5
Load data in caliber .25 WSSM with .257 | 120gr | Winchester Soft-Point bullet and 101 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are ReloadSwiss RS 70, Hodgdon Superformance 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>> | 82% | 56,043 psi | 88% | 2743 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 55,376 psi | 87% | 2772 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 56,869 psi | 89% | 2841 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 57,305 psi | 90% | 2835 fps | 98.2% |
| Accurate 3100ᴾ | <<locked>> | 100% | 46,064 psi | 72% | 2746 fps | 97.9% |
| Accurate 4064 | <<locked>> | 88% | 55,521 psi | 87% | 2825 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 55,883 psi | 88% | 2923 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 84% | 55,056 psi | 86% | 2851 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 56,318 psi | 88% | 2854 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 53,374 psi | 84% | 2894 fps | 96.8% |
| ADI Benchmark 8208 | <<locked>> | 84% | 57,348 psi | 90% | 2848 fps | 100% |
| Alliant AR-Comp | <<locked>> | 82% | 55,405 psi | 87% | 2772 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 54,998 psi | 86% | 2976 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 56,536 psi | 89% | 2877 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 57,188 psi | 90% | 2904 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 98% | 56,507 psi | 89% | 2976 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 92% | 54,215 psi | 85% | 2953 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 52,547 psi | 82% | 2887 fps | 96.8% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 43,482 psi | 68% | 2772 fps | 99.8% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 38,130 psi | 60% | 2671 fps | 96.4% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 49,037 psi | 77% | 2949 fps | 99.6% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 55,158 psi | 86% | 2871 fps | 99.9% |
| Bofors RP3 | <<locked>> | 90% | 57,305 psi | 90% | 2894 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 57,000 psi | 89% | 2871 fps | 98.4% |
| Hodgdon Benchmark | <<locked>> | 82% | 55,724 psi | 87% | 2785 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 57,551 psi | 90% | 2887 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 54,723 psi | 86% | 2861 fps | 99.7% |
| Hodgdon H414 | <<locked>> | 94% | 54,737 psi | 86% | 2920 fps | 98.6% |
| Hodgdon H4350 | <<locked>> | 92% | 55,013 psi | 86% | 2877 fps | 97.5% |
| Hodgdon H4895 | <<locked>> | 84% | 55,651 psi | 87% | 2861 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 56,623 psi | 89% | 2897 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 55,535 psi | 87% | 2897 fps | 100% |
| Hodgdon Superformance | <<locked>> | 94% | 54,795 psi | 86% | 2953 fps | 98.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,027 psi | 56% | 1752 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 56,797 psi | 89% | 2864 fps | 100% |
| IMR 3031 | <<locked>> | 84% | 55,985 psi | 88% | 2838 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 55,811 psi | 87% | 2838 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 86% | 55,593 psi | 87% | 2825 fps | 98.6% |
| IMR 4350 | <<locked>> | 98% | 57,551 psi | 90% | 2900 fps | 98.5% |
| IMR 4451 Enduron | <<locked>> | 92% | 55,419 psi | 87% | 2848 fps | 98.5% |
| IMR 4831 | <<locked>> | 98% | 56,130 psi | 88% | 2910 fps | 100% |
| IMR 4895 | <<locked>> | 86% | 55,158 psi | 86% | 2881 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 57,348 psi | 90% | 2848 fps | 100% |
| Lovex D073.6 | <<locked>> | 84% | 55,245 psi | 87% | 2828 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 54,447 psi | 85% | 2779 fps | 100% |
| Lovex S062 | <<locked>> | 88% | 55,854 psi | 88% | 2835 fps | 100% |
| Lovex S065 | <<locked>> | 94% | 55,143 psi | 86% | 2844 fps | 99.4% |
| Lovex S070 | <<locked>> | 96% | 56,304 psi | 88% | 2884 fps | 98.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 38,218 psi | 60% | 2595 fps | 95.9% |
| Norma 201 | <<locked>> | 86% | 57,421 psi | 90% | 2848 fps | 100% |
| Norma 202 | <<locked>> | 84% | 54,505 psi | 85% | 2795 fps | 100% |
| Norma 203B | <<locked>> | 88% | 56,391 psi | 88% | 2887 fps | 100% |
| Norma 204 | <<locked>> | 96% | 54,824 psi | 86% | 2900 fps | 97% |
| Norma MRPᴾ | <<locked>> | 100% | 48,776 psi | 76% | 2904 fps | 97.6% |
| Norma URP | <<locked>> | 96% | 54,592 psi | 86% | 2907 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 88% | 57,058 psi | 89% | 2913 fps | 100% |
| Ramshot Hunter | <<locked>> | 98% | 56,724 psi | 89% | 2956 fps | 99.4% |
| Ramshot TAC | <<locked>> | 82% | 54,259 psi | 85% | 2825 fps | 99.4% |
| Ramshot Wild Boar | <<locked>> | 82% | 53,998 psi | 85% | 2838 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,593 psi | 57% | 1795 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 54,694 psi | 86% | 2841 fps | 98.9% |
| ReloadSwiss RS 52 | <<locked>> | 84% | 54,172 psi | 85% | 2917 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 57,740 psi | 90% | 3005 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 96% | 55,550 psi | 87% | 2946 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 96% | 54,302 psi | 85% | 2969 fps | 99.8% |
| Rottweil R 901 | <<locked>> | 82% | 54,766 psi | 86% | 2776 fps | 100% |
| Rottweil R 902 | <<locked>> | 86% | 54,389 psi | 85% | 2795 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 57,566 psi | 90% | 2890 fps | 100% |
| Rottweil R 904ᴾ | <<locked>> | 100% | 55,143 psi | 86% | 2867 fps | 96% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 51,271 psi | 80% | 2867 fps | 96.7% |
| Rottweil R 907 | <<locked>> | 94% | 57,000 psi | 89% | 2871 fps | 98.4% |
| Shooters World Long Rifle | <<locked>> | 94% | 55,143 psi | 86% | 2844 fps | 99.4% |
| Shooters World Match Rifle | <<locked>> | 84% | 55,245 psi | 87% | 2828 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 55,854 psi | 88% | 2835 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 56,304 psi | 88% | 2884 fps | 98.9% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 55,288 psi | 87% | 2894 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 56,695 psi | 89% | 2861 fps | 99.8% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 57,348 psi | 90% | 2881 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 55,390 psi | 87% | 2736 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 55,869 psi | 88% | 2736 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 55,071 psi | 86% | 2795 fps | 98.5% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 50,778 psi | 80% | 2861 fps | 96.6% |
| Somchem S335 | <<locked>> | 84% | 54,665 psi | 86% | 2730 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 56,188 psi | 88% | 2844 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 57,464 psi | 90% | 2884 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 56,420 psi | 88% | 2956 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 52,214 psi | 82% | 2848 fps | 97.7% |
| Vihtavuori N133 | <<locked>> | 84% | 55,767 psi | 87% | 2720 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 54,491 psi | 85% | 2759 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 54,969 psi | 86% | 2776 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 55,521 psi | 87% | 2815 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 57,101 psi | 89% | 2904 fps | 99.9% |
| Vihtavuori N530 | <<locked>> | 82% | 54,331 psi | 85% | 2799 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 56,913 psi | 89% | 2822 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 55,883 psi | 88% | 2904 fps | 99.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 48,356 psi | 76% | 2851 fps | 99.8% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 56,927 psi | 89% | 2874 fps | 100% |
| Winchester 748 | <<locked>> | 82% | 54,795 psi | 86% | 2851 fps | 100% |
| Winchester 760 | <<locked>> | 94% | 54,737 psi | 86% | 2920 fps | 98.6% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 39,088 psi | 61% | 2802 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 86% | 57,246 psi | 90% | 2884 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% | 52,634 psi | 82% | 2697 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 45,585 psi | 71% | 2631 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 52,997 psi | 83% | 2785 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 44,179 psi | 69% | 2615 fps | 95.6% |
| Accurate 3100 | <<locked>> | 94% | 37,391 psi | 59% | 2579 fps | 95.6% |
| Accurate 4064 | <<locked>> | 80% | 43,120 psi | 68% | 2635 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 32,053 psi | 50% | 2467 fps | 95.6% |
| ADI AR 2206H | <<locked>> | 80% | 48,675 psi | 76% | 2749 fps | 99.9% |
| ADI AR 2208 | <<locked>> | 80% | 41,292 psi | 65% | 2598 fps | 98.7% |
| ADI AR 2209 | <<locked>> | 96% | 46,978 psi | 74% | 2782 fps | 95.2% |
| ADI Benchmark 8208 | <<locked>> | 80% | 50,749 psi | 80% | 2749 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 51,851 psi | 81% | 2726 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 44,730 psi | 70% | 2799 fps | 99.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 41,379 psi | 65% | 2625 fps | 99.6% |
| Alliant Reloder-15 | <<locked>> | 80% | 44,309 psi | 69% | 2690 fps | 99.3% |
| Alliant Reloder-16 | <<locked>> | 80% | 32,242 psi | 51% | 2484 fps | 95.7% |
| Alliant Reloder-17 | 38.5 gr | 80% | 35,897 psi | 56% | 2605 fps | 98.7% |
| Alliant Reloder-19 | <<locked>> | 96% | 46,398 psi | 73% | 2776 fps | 95.3% |
| Alliant Reloder-23 | <<locked>> | 86% | 28,079 psi | 44% | 2395 fps | 95.5% |
| Alliant Reloder-25 | <<locked>> | 98% | 35,882 psi | 56% | 2615 fps | 95.4% |
| Alliant Reloder-26 | <<locked>> | 90% | 34,461 psi | 54% | 2631 fps | 95.9% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 48,124 psi | 75% | 2759 fps | 99.5% |
| Bofors RP3 | <<locked>> | 80% | 41,307 psi | 65% | 2631 fps | 99.7% |
| Bofors RP7 | <<locked>> | 84% | 41,771 psi | 65% | 2602 fps | 95.1% |
| Hodgdon Benchmark | <<locked>> | 80% | 52,431 psi | 82% | 2736 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 50,111 psi | 79% | 2776 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 41,916 psi | 66% | 2638 fps | 98% |
| Hodgdon H414 | <<locked>> | 84% | 39,291 psi | 62% | 2635 fps | 95.1% |
| Hodgdon H4350 | <<locked>> | 86% | 45,368 psi | 71% | 2710 fps | 95.4% |
| Hodgdon H4895 | <<locked>> | 80% | 49,139 psi | 77% | 2759 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 29,573 psi | 46% | 2382 fps | 96.5% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 45,310 psi | 71% | 2733 fps | 100% |
| Hodgdon Superformance | 43.8 gr | 86% | 41,350 psi | 65% | 2703 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,861 psi | 42% | 1565 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 47,137 psi | 74% | 2710 fps | 99.9% |
| IMR 3031 | <<locked>> | 80% | 49,472 psi | 78% | 2746 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 43,395 psi | 68% | 2631 fps | 99.2% |
| IMR 4166 Enduron | <<locked>> | 80% | 45,963 psi | 72% | 2661 fps | 96.9% |
| IMR 4350 | <<locked>> | 88% | 42,322 psi | 66% | 2638 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 82% | 40,872 psi | 64% | 2585 fps | 95.4% |
| IMR 4831 | <<locked>> | 80% | 31,212 psi | 49% | 2431 fps | 95.3% |
| IMR 4895 | <<locked>> | 80% | 45,382 psi | 71% | 2720 fps | 99.7% |
| IMR 8208 XBR | <<locked>> | 80% | 50,749 psi | 80% | 2749 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 48,298 psi | 76% | 2726 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 48,196 psi | 76% | 2680 fps | 99.9% |
| Lovex S062 | <<locked>> | 80% | 43,540 psi | 68% | 2638 fps | 99.9% |
| Lovex S065 | <<locked>> | 80% | 35,839 psi | 56% | 2480 fps | 95.4% |
| Lovex S070 | <<locked>> | 84% | 38,624 psi | 61% | 2562 fps | 95.1% |
| Lovex S071 | <<locked>> | 98% | 35,752 psi | 56% | 2539 fps | 95% |
| Norma 201 | <<locked>> | 80% | 47,674 psi | 75% | 2697 fps | 100% |
| Norma 202 | <<locked>> | 80% | 48,095 psi | 75% | 2700 fps | 100% |
| Norma 203B | <<locked>> | 80% | 43,685 psi | 68% | 2677 fps | 99.5% |
| Norma 204 | <<locked>> | 92% | 47,906 psi | 75% | 2782 fps | 95.4% |
| Norma MRP | <<locked>> | 96% | 42,641 psi | 67% | 2782 fps | 96% |
| Norma URP | <<locked>> | 80% | 32,285 psi | 51% | 2470 fps | 95.5% |
| Ramshot Big Game | <<locked>> | 80% | 43,511 psi | 68% | 2694 fps | 99.4% |
| Ramshot Hunter | <<locked>> | 86% | 38,435 psi | 60% | 2625 fps | 95.8% |
| Ramshot TAC | <<locked>> | 80% | 50,749 psi | 80% | 2769 fps | 99% |
| Ramshot Wild Boar | <<locked>> | 80% | 50,459 psi | 79% | 2785 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,166 psi | 43% | 1601 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 42,250 psi | 66% | 2621 fps | 96.6% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 47,239 psi | 74% | 2799 fps | 99.6% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 38,159 psi | 60% | 2671 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 31,821 psi | 50% | 2484 fps | 95% |
| ReloadSwiss RS 70 | 40.1 gr | 82% | 33,808 psi | 53% | 2543 fps | 95% |
| Rottweil R 901 | <<locked>> | 80% | 51,866 psi | 81% | 2733 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 45,455 psi | 71% | 2651 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 38,827 psi | 61% | 2575 fps | 99.2% |
| Rottweil R 904 | <<locked>> | 98% | 51,750 psi | 81% | 2812 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 96% | 44,976 psi | 70% | 2753 fps | 95.2% |
| Rottweil R 907 | <<locked>> | 84% | 41,771 psi | 65% | 2602 fps | 95.1% |
| Shooters World Long Rifle | <<locked>> | 80% | 35,839 psi | 56% | 2480 fps | 95.4% |
| Shooters World Match Rifle | <<locked>> | 80% | 48,298 psi | 76% | 2726 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 43,540 psi | 68% | 2638 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 84% | 38,624 psi | 61% | 2562 fps | 95.1% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 39,813 psi | 62% | 2628 fps | 98.9% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 49,356 psi | 77% | 2746 fps | 99.2% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 47,152 psi | 74% | 2720 fps | 99.8% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 48,747 psi | 76% | 2641 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 40,872 psi | 64% | 2510 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 39,885 psi | 63% | 2530 fps | 95.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 44,541 psi | 70% | 2746 fps | 95% |
| Somchem S335 | <<locked>> | 80% | 48,428 psi | 76% | 2641 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 49,008 psi | 77% | 2736 fps | 99.9% |
| Somchem S355 | <<locked>> | 80% | 39,494 psi | 62% | 2579 fps | 99.2% |
| Somchem S365 | <<locked>> | 80% | 28,964 psi | 45% | 2421 fps | 97.8% |
| Somchem S385 | <<locked>> | 94% | 42,859 psi | 67% | 2684 fps | 95.5% |
| Vihtavuori N133 | <<locked>> | 80% | 49,197 psi | 77% | 2628 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 45,165 psi | 71% | 2625 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 45,571 psi | 71% | 2635 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 37,608 psi | 59% | 2513 fps | 99.6% |
| Vihtavuori N160 | <<locked>> | 80% | 33,634 psi | 53% | 2470 fps | 96% |
| Vihtavuori N530 | <<locked>> | 80% | 50,995 psi | 80% | 2749 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 43,976 psi | 69% | 2628 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 33,170 psi | 52% | 2474 fps | 95.6% |
| Vihtavuori N555 | <<locked>> | 86% | 30,443 psi | 48% | 2470 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 33,214 psi | 52% | 2448 fps | 98% |
| Winchester 748 | <<locked>> | 80% | 51,082 psi | 80% | 2795 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 39,291 psi | 62% | 2635 fps | 95.1% |
| Winchester StaBALL HD | <<locked>> | 90% | 28,108 psi | 44% | 2474 fps | 96.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 46,847 psi | 73% | 2723 fps | 99.9% |
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 101 powders for .25 WSSM loaded with the .257 | 120gr | Winchester Soft-Point. ReloadSwiss RS 60 delivers the highest muzzle velocity at 3,005 fps; across all powders the maximum-charge window runs from 1,752 fps to 3,005 fps. Accurate 3100 gives the best case fill at 100 %, and 101 of the 101 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 120.0 gr projectile in 0.257" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, Alliant Reloder-19 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, Hodgdon Superformance, Alliant Reloder-17 rank at the top here: for .25 WSSM with the .257 | 120gr | Winchester Soft-Point 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.