Load Specifications
Load data in caliber .25 WSSM with .257 | 120gr | Speer Spitzer 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% | 54,708 psi | 86% | 2720 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 54,041 psi | 85% | 2749 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 55,274 psi | 87% | 2812 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 56,043 psi | 88% | 2802 fps | 97.9% |
| Accurate 3100ᴾ | <<locked>> | 100% | 44,512 psi | 70% | 2713 fps | 97.5% |
| Accurate 4064 | <<locked>> | 90% | 57,421 psi | 90% | 2844 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 53,998 psi | 85% | 2887 fps | 99.8% |
| ADI AR 2206H | <<locked>> | 86% | 57,392 psi | 90% | 2877 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 54,940 psi | 86% | 2828 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 52,286 psi | 82% | 2867 fps | 96.4% |
| ADI Benchmark 8208 | <<locked>> | 84% | 56,231 psi | 88% | 2825 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 57,682 psi | 90% | 2795 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 57,609 psi | 90% | 3005 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 55,463 psi | 87% | 2854 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 55,738 psi | 87% | 2874 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 98% | 55,201 psi | 87% | 2946 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 94% | 56,521 psi | 89% | 2979 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 51,111 psi | 80% | 2854 fps | 96.3% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 42,148 psi | 66% | 2740 fps | 99.7% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 47,703 psi | 75% | 2917 fps | 99.3% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 57,638 psi | 90% | 2900 fps | 100% |
| Bofors RP3 | <<locked>> | 90% | 56,246 psi | 88% | 2871 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 55,738 psi | 87% | 2841 fps | 98.1% |
| Hodgdon Benchmark | <<locked>> | 82% | 54,563 psi | 86% | 2759 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 56,072 psi | 88% | 2858 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 56,869 psi | 89% | 2884 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 96% | 56,594 psi | 89% | 2936 fps | 98.8% |
| Hodgdon H4350 | <<locked>> | 94% | 57,217 psi | 90% | 2900 fps | 97.7% |
| Hodgdon H4895 | <<locked>> | 84% | 54,476 psi | 85% | 2835 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 54,824 psi | 86% | 2864 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 54,070 psi | 85% | 2871 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 57,464 psi | 90% | 2982 fps | 98.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,810 psi | 56% | 1739 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 55,695 psi | 87% | 2838 fps | 100% |
| IMR 3031 | <<locked>> | 84% | 54,969 psi | 86% | 2818 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 54,737 psi | 86% | 2815 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 86% | 54,288 psi | 85% | 2792 fps | 98.3% |
| IMR 4350 | <<locked>> | 98% | 56,420 psi | 88% | 2871 fps | 98.2% |
| IMR 4451 Enduron | <<locked>> | 94% | 57,638 psi | 90% | 2874 fps | 98.7% |
| IMR 4831 | <<locked>> | 98% | 54,447 psi | 85% | 2877 fps | 99.9% |
| IMR 4895 | <<locked>> | 88% | 57,116 psi | 90% | 2900 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 56,231 psi | 88% | 2825 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 57,682 psi | 90% | 2854 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 56,782 psi | 89% | 2805 fps | 100% |
| Lovex S062 | <<locked>> | 88% | 54,723 psi | 86% | 2808 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 57,348 psi | 90% | 2867 fps | 99.5% |
| Lovex S070 | <<locked>> | 96% | 54,694 psi | 86% | 2848 fps | 98.6% |
| Norma 201 | <<locked>> | 86% | 56,217 psi | 88% | 2822 fps | 100% |
| Norma 202 | <<locked>> | 86% | 56,811 psi | 89% | 2818 fps | 100% |
| Norma 203B | <<locked>> | 88% | 54,940 psi | 86% | 2861 fps | 100% |
| Norma 204 | <<locked>> | 98% | 56,927 psi | 89% | 2920 fps | 97.2% |
| Norma MRPᴾ | <<locked>> | 100% | 47,471 psi | 74% | 2871 fps | 97.1% |
| Norma URP | <<locked>> | 98% | 56,434 psi | 88% | 2927 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 88% | 55,651 psi | 87% | 2887 fps | 100% |
| Ramshot Hunter | <<locked>> | 98% | 55,158 psi | 86% | 2923 fps | 99.2% |
| Ramshot TAC | <<locked>> | 84% | 56,666 psi | 89% | 2851 fps | 99.5% |
| Ramshot Wild Boar | <<locked>> | 84% | 56,391 psi | 88% | 2864 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 57,072 psi | 89% | 2828 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,376 psi | 57% | 1781 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 56,826 psi | 89% | 2864 fps | 99.1% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 56,594 psi | 89% | 2943 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 55,927 psi | 88% | 2972 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 57,508 psi | 90% | 2966 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 56,826 psi | 89% | 2999 fps | 99.9% |
| Rottweil R 901 | <<locked>> | 84% | 57,348 psi | 90% | 2802 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 56,710 psi | 89% | 2822 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 56,043 psi | 88% | 2861 fps | 100% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 50,038 psi | 78% | 2838 fps | 96.3% |
| Rottweil R 907 | <<locked>> | 94% | 55,738 psi | 87% | 2841 fps | 98.1% |
| Shooters World Long Rifle | <<locked>> | 96% | 57,348 psi | 90% | 2867 fps | 99.5% |
| Shooters World Match Rifle | <<locked>> | 86% | 57,682 psi | 90% | 2854 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 54,723 psi | 86% | 2808 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 54,694 psi | 86% | 2848 fps | 98.6% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 53,954 psi | 85% | 2867 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 55,317 psi | 87% | 2831 fps | 99.6% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 55,970 psi | 88% | 2851 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 57,392 psi | 90% | 2753 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 54,375 psi | 85% | 2707 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 57,566 psi | 90% | 2822 fps | 98.7% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 49,559 psi | 78% | 2831 fps | 96.1% |
| Somchem S321 | <<locked>> | 82% | 57,595 psi | 90% | 2858 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 56,985 psi | 89% | 2753 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 54,824 psi | 86% | 2818 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 56,057 psi | 88% | 2854 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 55,013 psi | 86% | 2930 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 50,734 psi | 80% | 2815 fps | 97.2% |
| Vihtavuori N130 | <<locked>> | 82% | 56,971 psi | 89% | 2710 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 57,696 psi | 90% | 2736 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 56,826 psi | 89% | 2782 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 57,392 psi | 90% | 2799 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 54,172 psi | 85% | 2785 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 55,390 psi | 87% | 2871 fps | 99.8% |
| Vihtavuori N530 | <<locked>> | 84% | 56,710 psi | 89% | 2822 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 55,564 psi | 87% | 2799 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 54,259 psi | 85% | 2874 fps | 99.7% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 46,717 psi | 73% | 2815 fps | 99.6% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 55,521 psi | 87% | 2848 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 57,203 psi | 90% | 2874 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 56,985 psi | 89% | 2943 fps | 98.8% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 37,985 psi | 60% | 2766 fps | 99.8% |
| Winchester StaBALL Match | <<locked>> | 86% | 55,825 psi | 87% | 2858 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% | 51,677 psi | 81% | 2677 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 44,599 psi | 70% | 2612 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 51,808 psi | 81% | 2762 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 43,250 psi | 68% | 2585 fps | 95.1% |
| Accurate 3100 | <<locked>> | 94% | 36,230 psi | 57% | 2546 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 42,206 psi | 66% | 2612 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 31,038 psi | 49% | 2438 fps | 95% |
| ADI AR 2206H | <<locked>> | 80% | 47,529 psi | 74% | 2723 fps | 99.8% |
| ADI AR 2208 | <<locked>> | 80% | 40,524 psi | 64% | 2575 fps | 98.5% |
| ADI AR 2209 | <<locked>> | 98% | 48,994 psi | 77% | 2808 fps | 95.5% |
| ADI Benchmark 8208 | <<locked>> | 80% | 49,574 psi | 78% | 2723 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 50,749 psi | 80% | 2703 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 43,714 psi | 69% | 2769 fps | 99.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 40,524 psi | 64% | 2602 fps | 99.5% |
| Alliant Reloder-15 | <<locked>> | 80% | 43,192 psi | 68% | 2661 fps | 99.1% |
| Alliant Reloder-16 | <<locked>> | 80% | 31,372 psi | 49% | 2451 fps | 95.1% |
| Alliant Reloder-17 | 37.6 gr | 80% | 35,012 psi | 55% | 2579 fps | 98.3% |
| Alliant Reloder-19 | <<locked>> | 98% | 47,964 psi | 75% | 2799 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 88% | 29,153 psi | 46% | 2418 fps | 95.9% |
| Alliant Reloder-26 | <<locked>> | 90% | 33,315 psi | 52% | 2589 fps | 95.1% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 47,137 psi | 74% | 2733 fps | 99.3% |
| Bofors RP3 | <<locked>> | 80% | 40,176 psi | 63% | 2605 fps | 99.5% |
| Bofors RP7 | <<locked>> | 86% | 43,511 psi | 68% | 2628 fps | 95.4% |
| Hodgdon Benchmark | <<locked>> | 80% | 51,314 psi | 80% | 2710 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 49,023 psi | 77% | 2753 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 40,886 psi | 64% | 2608 fps | 97.6% |
| Hodgdon H414 | <<locked>> | 86% | 40,625 psi | 64% | 2654 fps | 95.4% |
| Hodgdon H4350 | <<locked>> | 88% | 47,369 psi | 74% | 2740 fps | 95.7% |
| Hodgdon H4895 | <<locked>> | 80% | 48,008 psi | 75% | 2733 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 28,906 psi | 45% | 2356 fps | 96% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 44,193 psi | 69% | 2707 fps | 99.9% |
| Hodgdon Superformance | 43.7 gr | 88% | 43,033 psi | 67% | 2730 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,760 psi | 42% | 1555 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 46,021 psi | 72% | 2684 fps | 99.8% |
| IMR 3031 | <<locked>> | 80% | 48,051 psi | 75% | 2720 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 42,583 psi | 67% | 2608 fps | 99% |
| IMR 4166 Enduron | <<locked>> | 80% | 45,005 psi | 71% | 2631 fps | 96.5% |
| IMR 4350 | <<locked>> | 90% | 43,845 psi | 69% | 2657 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 84% | 42,569 psi | 67% | 2612 fps | 95.7% |
| IMR 4831 | <<locked>> | 82% | 32,329 psi | 51% | 2454 fps | 95.6% |
| IMR 4895 | <<locked>> | 80% | 44,251 psi | 69% | 2690 fps | 99.5% |
| IMR 8208 XBR | <<locked>> | 80% | 49,574 psi | 78% | 2723 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 47,094 psi | 74% | 2700 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 47,413 psi | 74% | 2657 fps | 99.8% |
| Lovex S062 | <<locked>> | 80% | 42,699 psi | 67% | 2615 fps | 99.8% |
| Lovex S065 | <<locked>> | 82% | 37,173 psi | 58% | 2503 fps | 95.7% |
| Lovex S070 | <<locked>> | 86% | 40,147 psi | 63% | 2589 fps | 95.4% |
| Norma 201 | <<locked>> | 80% | 46,804 psi | 73% | 2674 fps | 100% |
| Norma 202 | <<locked>> | 80% | 47,239 psi | 74% | 2680 fps | 100% |
| Norma 203B | <<locked>> | 80% | 42,554 psi | 67% | 2648 fps | 99.3% |
| Norma 204 | <<locked>> | 94% | 49,922 psi | 78% | 2808 fps | 95.8% |
| Norma MRP | <<locked>> | 96% | 41,365 psi | 65% | 2746 fps | 95.3% |
| Norma URP | <<locked>> | 80% | 31,575 psi | 49% | 2444 fps | 95% |
| Ramshot Big Game | <<locked>> | 80% | 42,496 psi | 67% | 2667 fps | 99.2% |
| Ramshot Hunter | <<locked>> | 86% | 37,318 psi | 58% | 2592 fps | 95.2% |
| Ramshot TAC | <<locked>> | 80% | 49,530 psi | 78% | 2740 fps | 98.7% |
| Ramshot Wild Boar | <<locked>> | 80% | 49,400 psi | 77% | 2759 fps | 99.9% |
| Ramshot X-Terminator | <<locked>> | 80% | 53,722 psi | 84% | 2779 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,050 psi | 42% | 1591 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 41,249 psi | 65% | 2592 fps | 96.1% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 45,992 psi | 72% | 2769 fps | 99.4% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 37,246 psi | 58% | 2641 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 33,069 psi | 52% | 2510 fps | 95.4% |
| ReloadSwiss RS 70 | 40.1 gr | 84% | 35,259 psi | 55% | 2572 fps | 95.4% |
| Rottweil R 901 | <<locked>> | 80% | 50,952 psi | 80% | 2710 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 44,599 psi | 70% | 2628 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 80% | 38,014 psi | 60% | 2552 fps | 99% |
| Rottweil R 905 | <<locked>> | 98% | 46,804 psi | 73% | 2779 fps | 95.4% |
| Rottweil R 907 | <<locked>> | 86% | 43,511 psi | 68% | 2628 fps | 95.4% |
| Shooters World Long Rifle | <<locked>> | 82% | 37,173 psi | 58% | 2503 fps | 95.7% |
| Shooters World Match Rifle | <<locked>> | 80% | 47,094 psi | 74% | 2700 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 42,699 psi | 67% | 2615 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 86% | 40,147 psi | 63% | 2589 fps | 95.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 38,783 psi | 61% | 2598 fps | 98.6% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 48,327 psi | 76% | 2720 fps | 98.9% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 46,108 psi | 72% | 2694 fps | 99.7% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 47,892 psi | 75% | 2618 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 40,045 psi | 63% | 2490 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 41,582 psi | 65% | 2556 fps | 95.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 46,354 psi | 73% | 2772 fps | 95.3% |
| Somchem S321 | <<locked>> | 80% | 54,128 psi | 85% | 2808 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 47,630 psi | 75% | 2621 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 47,964 psi | 75% | 2713 fps | 99.8% |
| Somchem S355 | <<locked>> | 80% | 38,667 psi | 61% | 2556 fps | 99% |
| Somchem S365 | <<locked>> | 80% | 28,108 psi | 44% | 2392 fps | 97.2% |
| Somchem S385 | <<locked>> | 96% | 44,556 psi | 70% | 2707 fps | 95.8% |
| Vihtavuori N130 | <<locked>> | 80% | 53,824 psi | 84% | 2671 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 48,269 psi | 76% | 2608 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 44,193 psi | 69% | 2602 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 44,759 psi | 70% | 2615 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 36,840 psi | 58% | 2493 fps | 99.5% |
| Vihtavuori N160 | <<locked>> | 80% | 32,648 psi | 51% | 2441 fps | 95.4% |
| Vihtavuori N530 | <<locked>> | 80% | 49,821 psi | 78% | 2720 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 42,960 psi | 67% | 2602 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 32,242 psi | 51% | 2441 fps | 95% |
| Vihtavuori N555 | <<locked>> | 86% | 29,530 psi | 46% | 2441 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 32,532 psi | 51% | 2421 fps | 97.7% |
| Winchester 748 | <<locked>> | 80% | 49,908 psi | 78% | 2769 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 40,915 psi | 64% | 2661 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 90% | 27,369 psi | 43% | 2434 fps | 95.3% |
| Winchester StaBALL Match | <<locked>> | 80% | 45,818 psi | 72% | 2700 fps | 99.8% |
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 119 powders for .25 WSSM loaded with the .257 | 120gr | Speer Spitzer Soft Point. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,005 fps; across all powders the maximum-charge window runs from 1,739 fps to 3,005 fps. Accurate 3100 gives the best case fill at 100 %, and 119 of the 119 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 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate MAGPRO, ADI AR 2209 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 | Speer Spitzer Soft Point they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate MAGPRO, ADI AR 2213, Alliant Reloder-22 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.