Load Specifications
Bullet Manufacturer:Sierra
Bullet Weight:117 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:1:10.5
Load data in caliber .25 WSSM with .257 | 117gr | Sierra GameKing bullet and 99 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-17, ReloadSwiss RS 60 and Hodgdon H414.
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% | 57,508 psi | 90% | 2792 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 56,739 psi | 89% | 2822 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 56,652 psi | 89% | 2877 fps | 100% |
| Accurate 2700 | <<locked>> | 92% | 56,420 psi | 88% | 2831 fps | 97.7% |
| Accurate 3100ᴾ | <<locked>> | 100% | 43,497 psi | 68% | 2726 fps | 97% |
| Accurate 4064 | <<locked>> | 90% | 56,376 psi | 88% | 2867 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 56,623 psi | 89% | 2963 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 86% | 56,507 psi | 89% | 2900 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 57,566 psi | 90% | 2900 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 84% | 55,405 psi | 87% | 2848 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 56,710 psi | 89% | 2822 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 56,521 psi | 89% | 3028 fps | 100% |
| Alliant Power Pro Varmintᴾ | <<locked>> | 100% | 50,865 psi | 80% | 2877 fps | 95.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 54,520 psi | 85% | 2877 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 54,795 psi | 86% | 2894 fps | 99.9% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 57,334 psi | 90% | 3015 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 94% | 55,332 psi | 87% | 3002 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 41,249 psi | 65% | 2753 fps | 99.4% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 46,557 psi | 73% | 2927 fps | 99% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 56,652 psi | 89% | 2920 fps | 99.9% |
| Bofors RP3 | <<locked>> | 90% | 55,201 psi | 87% | 2890 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 54,810 psi | 86% | 2861 fps | 97.7% |
| Hodgdon Benchmark | <<locked>> | 84% | 57,232 psi | 90% | 2831 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 55,100 psi | 86% | 2881 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 57,392 psi | 90% | 2989 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 55,869 psi | 88% | 2904 fps | 99.6% |
| Hodgdon H414 | <<locked>> | 96% | 55,477 psi | 87% | 2956 fps | 98.4% |
| Hodgdon H4350 | <<locked>> | 94% | 56,231 psi | 88% | 2920 fps | 97.3% |
| Hodgdon H4895 | <<locked>> | 86% | 57,087 psi | 89% | 2910 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 54,056 psi | 85% | 2890 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 88% | 56,985 psi | 89% | 2946 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 56,246 psi | 88% | 2995 fps | 98.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,607 psi | 56% | 1759 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 54,839 psi | 86% | 2861 fps | 100% |
| IMR 3031 | <<locked>> | 86% | 57,334 psi | 90% | 2887 fps | 100% |
| IMR 4064 | <<locked>> | 90% | 57,014 psi | 89% | 2884 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 88% | 56,913 psi | 89% | 2867 fps | 98.5% |
| IMR 4350 | <<locked>> | 98% | 55,405 psi | 87% | 2890 fps | 97.8% |
| IMR 4451 Enduron | <<locked>> | 94% | 56,753 psi | 89% | 2894 fps | 98.4% |
| IMR 4831ᴾ | <<locked>> | 100% | 56,942 psi | 89% | 2949 fps | 99.9% |
| IMR 4895 | <<locked>> | 88% | 56,217 psi | 88% | 2927 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 55,405 psi | 87% | 2848 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 56,652 psi | 89% | 2877 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 56,014 psi | 88% | 2828 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 56,971 psi | 89% | 2877 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 56,362 psi | 88% | 2887 fps | 99.3% |
| Lovex S070 | <<locked>> | 98% | 57,217 psi | 90% | 2923 fps | 98.7% |
| Norma 201 | <<locked>> | 86% | 55,376 psi | 87% | 2844 fps | 100% |
| Norma 202 | <<locked>> | 86% | 55,927 psi | 88% | 2844 fps | 100% |
| Norma 203B | <<locked>> | 90% | 57,522 psi | 90% | 2933 fps | 100% |
| Norma 204 | <<locked>> | 98% | 56,231 psi | 88% | 2943 fps | 96.8% |
| Norma MRPᴾ | <<locked>> | 100% | 46,412 psi | 73% | 2884 fps | 96.5% |
| Norma URP | <<locked>> | 98% | 55,288 psi | 87% | 2946 fps | 99.8% |
| Ramshot Big Game | <<locked>> | 88% | 54,679 psi | 86% | 2907 fps | 100% |
| Ramshot Hunter | <<locked>> | 98% | 54,447 psi | 85% | 2946 fps | 98.9% |
| Ramshot TAC | <<locked>> | 84% | 55,825 psi | 87% | 2874 fps | 99.3% |
| Ramshot Wild Boar | <<locked>> | 84% | 55,463 psi | 87% | 2890 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 56,231 psi | 88% | 2851 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,143 psi | 57% | 1801 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 56,289 psi | 88% | 2890 fps | 98.8% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 55,506 psi | 87% | 2963 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 54,824 psi | 86% | 2992 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 56,275 psi | 88% | 2982 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 55,724 psi | 87% | 3015 fps | 99.7% |
| Rottweil R 901 | <<locked>> | 84% | 56,130 psi | 88% | 2822 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 55,840 psi | 88% | 2844 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 55,071 psi | 86% | 2884 fps | 100% |
| Rottweil R 907 | <<locked>> | 94% | 54,810 psi | 86% | 2861 fps | 97.7% |
| Shooters World Long Rifle | <<locked>> | 96% | 56,362 psi | 88% | 2887 fps | 99.3% |
| Shooters World Match Rifle | <<locked>> | 86% | 56,652 psi | 89% | 2877 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 56,971 psi | 89% | 2877 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 57,217 psi | 90% | 2923 fps | 98.7% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 56,782 psi | 89% | 2946 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 54,375 psi | 85% | 2851 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 55,071 psi | 86% | 2874 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 56,565 psi | 89% | 2779 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 57,174 psi | 90% | 2779 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 56,536 psi | 89% | 2841 fps | 98.4% |
| Somchem S321 | <<locked>> | 82% | 56,681 psi | 89% | 2881 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 56,173 psi | 88% | 2779 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 53,896 psi | 84% | 2841 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 55,085 psi | 86% | 2877 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 53,708 psi | 84% | 2949 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 49,705 psi | 78% | 2831 fps | 96.7% |
| Vihtavuori N130 | <<locked>> | 82% | 56,217 psi | 88% | 2736 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 56,869 psi | 89% | 2759 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 55,825 psi | 87% | 2805 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 56,478 psi | 89% | 2825 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 56,797 psi | 89% | 2858 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 54,302 psi | 85% | 2890 fps | 99.7% |
| Vihtavuori N530 | <<locked>> | 84% | 55,840 psi | 88% | 2848 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 54,650 psi | 86% | 2822 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 57,130 psi | 90% | 2949 fps | 99.8% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 45,585 psi | 71% | 2831 fps | 99.3% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 54,505 psi | 85% | 2867 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 56,217 psi | 88% | 2900 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 55,912 psi | 88% | 2963 fps | 98.5% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 37,159 psi | 58% | 2772 fps | 99.6% |
| Winchester StaBALL Match | <<locked>> | 86% | 54,882 psi | 86% | 2877 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% | 50,923 psi | 80% | 2703 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 43,801 psi | 69% | 2635 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 49,400 psi | 77% | 2772 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 46,456 psi | 73% | 2667 fps | 95.7% |
| Accurate 3100 | <<locked>> | 96% | 37,884 psi | 59% | 2615 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 41,408 psi | 65% | 2631 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 32,547 psi | 51% | 2507 fps | 95.3% |
| ADI AR 2206H | <<locked>> | 80% | 46,804 psi | 73% | 2743 fps | 99.6% |
| ADI AR 2208 | <<locked>> | 80% | 39,929 psi | 63% | 2595 fps | 98.1% |
| ADI Benchmark 8208 | <<locked>> | 80% | 48,849 psi | 77% | 2746 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 49,893 psi | 78% | 2730 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 42,931 psi | 67% | 2785 fps | 98.8% |
| Alliant Power Pro Varmint | <<locked>> | 98% | 47,747 psi | 75% | 2822 fps | 95.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 39,537 psi | 62% | 2615 fps | 99.2% |
| Alliant Reloder-15 | <<locked>> | 80% | 42,467 psi | 67% | 2680 fps | 98.8% |
| Alliant Reloder-16 | <<locked>> | 82% | 32,895 psi | 52% | 2523 fps | 95.5% |
| Alliant Reloder-17 | 37.7 gr | 80% | 34,374 psi | 54% | 2592 fps | 97.9% |
| Alliant Reloder-23 | <<locked>> | 88% | 28,601 psi | 45% | 2431 fps | 95.2% |
| Alliant Reloder-26 | <<locked>> | 92% | 35,012 psi | 55% | 2664 fps | 95.6% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 46,340 psi | 73% | 2753 fps | 99% |
| Bofors RP3 | <<locked>> | 80% | 39,421 psi | 62% | 2621 fps | 99.3% |
| Bofors RP7 | <<locked>> | 88% | 45,614 psi | 71% | 2700 fps | 95.7% |
| Hodgdon Benchmark | <<locked>> | 80% | 50,618 psi | 79% | 2736 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 48,196 psi | 76% | 2776 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 53,374 psi | 84% | 2927 fps | 99.9% |
| Hodgdon H380 | <<locked>> | 80% | 40,176 psi | 63% | 2625 fps | 97.2% |
| Hodgdon H414 | 40.6 gr | 88% | 42,830 psi | 67% | 2733 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 88% | 46,543 psi | 73% | 2756 fps | 95.2% |
| Hodgdon H4895 | <<locked>> | 80% | 47,239 psi | 74% | 2753 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 28,398 psi | 45% | 2369 fps | 95.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 43,366 psi | 68% | 2726 fps | 99.7% |
| Hodgdon Superformance | <<locked>> | 90% | 45,324 psi | 71% | 2805 fps | 95.9% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,585 psi | 42% | 1572 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 45,339 psi | 71% | 2707 fps | 99.7% |
| IMR 3031 | <<locked>> | 80% | 47,239 psi | 74% | 2743 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 41,945 psi | 66% | 2628 fps | 98.7% |
| IMR 4166 Enduron | <<locked>> | 80% | 44,367 psi | 70% | 2651 fps | 96% |
| IMR 4350 | <<locked>> | 90% | 43,120 psi | 68% | 2677 fps | 95.1% |
| IMR 4451 Enduron | <<locked>> | 84% | 41,872 psi | 66% | 2628 fps | 95.2% |
| IMR 4831 | <<locked>> | 82% | 31,676 psi | 50% | 2467 fps | 95% |
| IMR 4895 | <<locked>> | 80% | 43,497 psi | 68% | 2710 fps | 99.3% |
| IMR 8208 XBR | <<locked>> | 80% | 48,849 psi | 77% | 2746 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 46,267 psi | 73% | 2720 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 46,789 psi | 73% | 2680 fps | 99.6% |
| Lovex S062 | <<locked>> | 80% | 42,047 psi | 66% | 2635 fps | 99.7% |
| Lovex S065 | <<locked>> | 82% | 36,579 psi | 57% | 2520 fps | 95.2% |
| Lovex S070 | <<locked>> | 88% | 42,032 psi | 66% | 2657 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 46,093 psi | 72% | 2697 fps | 99.9% |
| Norma 202 | <<locked>> | 80% | 46,180 psi | 72% | 2697 fps | 100% |
| Norma 203B | <<locked>> | 80% | 41,843 psi | 66% | 2667 fps | 99% |
| Norma 204 | <<locked>> | 94% | 48,950 psi | 77% | 2822 fps | 95.2% |
| Norma MRP | <<locked>> | 98% | 43,192 psi | 68% | 2815 fps | 95.6% |
| Norma URP | <<locked>> | 82% | 32,837 psi | 51% | 2510 fps | 95.3% |
| Ramshot Big Game | <<locked>> | 80% | 41,713 psi | 65% | 2687 fps | 98.9% |
| Ramshot Hunter | <<locked>> | 88% | 39,030 psi | 61% | 2661 fps | 95.5% |
| Ramshot TAC | <<locked>> | 80% | 48,776 psi | 76% | 2759 fps | 98.4% |
| Ramshot Wild Boar | <<locked>> | 80% | 48,588 psi | 76% | 2779 fps | 99.8% |
| Ramshot X-Terminator | <<locked>> | 80% | 52,939 psi | 83% | 2802 fps | 99.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,876 psi | 42% | 1608 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 40,582 psi | 64% | 2608 fps | 95.6% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 45,121 psi | 71% | 2789 fps | 99.2% |
| ReloadSwiss RS 60 | 37.7 gr | 80% | 36,564 psi | 57% | 2657 fps | 99.9% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 34,563 psi | 54% | 2579 fps | 95.7% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 36,883 psi | 58% | 2641 fps | 95.7% |
| Rottweil R 901 | <<locked>> | 80% | 49,850 psi | 78% | 2730 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 43,598 psi | 68% | 2644 fps | 99.8% |
| Rottweil R 903 | <<locked>> | 80% | 37,043 psi | 58% | 2566 fps | 98.7% |
| Rottweil R 907 | <<locked>> | 88% | 45,614 psi | 71% | 2700 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 82% | 36,579 psi | 57% | 2520 fps | 95.2% |
| Shooters World Match Rifle | <<locked>> | 80% | 46,267 psi | 73% | 2720 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 42,047 psi | 66% | 2635 fps | 99.7% |
| Shooters World SW4350 | <<locked>> | 88% | 42,032 psi | 66% | 2657 fps | 95.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 38,072 psi | 60% | 2615 fps | 98.2% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 47,529 psi | 74% | 2740 fps | 98.6% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 45,368 psi | 71% | 2713 fps | 99.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 47,195 psi | 74% | 2641 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 39,465 psi | 62% | 2510 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 40,872 psi | 64% | 2572 fps | 95.1% |
| Somchem S321 | <<locked>> | 80% | 53,272 psi | 83% | 2831 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 46,963 psi | 74% | 2644 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 47,152 psi | 74% | 2733 fps | 99.6% |
| Somchem S355 | <<locked>> | 80% | 38,029 psi | 60% | 2575 fps | 98.7% |
| Somchem S365 | <<locked>> | 80% | 27,557 psi | 43% | 2402 fps | 96.6% |
| Somchem S385 | <<locked>> | 96% | 43,598 psi | 68% | 2720 fps | 95.2% |
| Vihtavuori N130 | <<locked>> | 80% | 53,156 psi | 83% | 2697 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 47,616 psi | 75% | 2631 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 43,482 psi | 68% | 2625 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 43,758 psi | 69% | 2631 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 35,926 psi | 56% | 2503 fps | 99.2% |
| Vihtavuori N160 | <<locked>> | 82% | 34,272 psi | 54% | 2510 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 49,066 psi | 77% | 2746 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 42,279 psi | 66% | 2625 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 33,750 psi | 53% | 2510 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 88% | 30,879 psi | 48% | 2507 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 31,966 psi | 50% | 2434 fps | 97.2% |
| Winchester 748 | <<locked>> | 80% | 49,052 psi | 77% | 2792 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 42,830 psi | 67% | 2733 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 92% | 28,703 psi | 45% | 2510 fps | 95.8% |
| Winchester StaBALL Match | <<locked>> | 80% | 45,034 psi | 71% | 2720 fps | 99.7% |
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 99 powders for .25 WSSM loaded with the .257 | 117gr | Sierra GameKing. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,028 fps; across all powders the maximum-charge window runs from 1,759 fps to 3,028 fps. Accurate 3100 gives the best case fill at 100 %, and 99 of the 99 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 117.0 gr projectile in 0.257" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Power Pro Varmint, Alliant Reloder-16 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 Reloder-17, ReloadSwiss RS 60, Hodgdon H414 rank at the top here: for .25 WSSM with the .257 | 117gr | Sierra GameKing 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.