Load Specifications
Bullet Manufacturer:Swift
Bullet Weight:100 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:1:9.5
Load data in caliber .25 WSSM with .257 | 100gr | Swift Scirocco bullet and 102 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 Power Pro 2000-MR and ReloadSwiss RS 52.
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>> | 86% | 54,186 psi | 85% | 2966 fps | 100% |
| Accurate 2460 | <<locked>> | 84% | 56,405 psi | 88% | 3045 fps | 100% |
| Accurate 2495 | <<locked>> | 92% | 56,014 psi | 88% | 3035 fps | 100% |
| Accurate 2520 | <<locked>> | 86% | 54,563 psi | 86% | 3054 fps | 100% |
| Accurate 4064 | <<locked>> | 94% | 55,941 psi | 88% | 3081 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 51,459 psi | 81% | 3087 fps | 98.4% |
| Accurate LT-30 | <<locked>> | 82% | 56,710 psi | 89% | 2956 fps | 100% |
| Accurate LT-32 | <<locked>> | 82% | 57,116 psi | 90% | 2986 fps | 100% |
| ADI AR 2206H | <<locked>> | 90% | 56,942 psi | 89% | 3117 fps | 99.7% |
| ADI AR 2208 | <<locked>> | 94% | 54,230 psi | 85% | 3054 fps | 99.1% |
| ADI Benchmark 8208 | <<locked>> | 88% | 55,956 psi | 88% | 3068 fps | 100% |
| Alliant AR-Comp | <<locked>> | 88% | 56,231 psi | 88% | 3045 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 84% | 57,653 psi | 90% | 3182 fps | 99.9% |
| Alliant Power Pro 2000-MR | <<locked>> | 92% | 56,391 psi | 88% | 3235 fps | 99.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 96% | 57,653 psi | 90% | 3133 fps | 100% |
| Alliant Reloder-10x | <<locked>> | 84% | 57,348 psi | 90% | 3025 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 92% | 54,824 psi | 86% | 3100 fps | 99.3% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 50,285 psi | 79% | 3094 fps | 98.5% |
| Alliant Reloder-17 | <<locked>> | 98% | 54,795 psi | 86% | 3202 fps | 99.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 35,708 psi | 56% | 2792 fps | 96% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 56,043 psi | 88% | 2949 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 90% | 56,666 psi | 89% | 3127 fps | 99.2% |
| Bofors RP3 | <<locked>> | 94% | 54,476 psi | 85% | 3094 fps | 99.9% |
| Bofors RP7 | <<locked>> | 98% | 54,897 psi | 86% | 3048 fps | 95.8% |
| Hodgdon Benchmark | <<locked>> | 86% | 54,418 psi | 85% | 2999 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 88% | 55,027 psi | 86% | 3094 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 86% | 57,363 psi | 90% | 3202 fps | 99.6% |
| Hodgdon H322 | <<locked>> | 84% | 56,753 psi | 89% | 3068 fps | 100% |
| Hodgdon H335 | <<locked>> | 82% | 54,056 psi | 85% | 3038 fps | 100% |
| Hodgdon H380 | <<locked>> | 94% | 55,970 psi | 88% | 3107 fps | 98.6% |
| Hodgdon H414ᴾ | <<locked>> | 100% | 54,940 psi | 86% | 3143 fps | 96.6% |
| Hodgdon H4895 | <<locked>> | 90% | 57,464 psi | 90% | 3127 fps | 99.9% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 46,369 psi | 73% | 2966 fps | 98.9% |
| Hodgdon LEVERevolution | <<locked>> | 92% | 56,608 psi | 89% | 3159 fps | 100% |
| Hodgdon Superformanceᴾ | <<locked>> | 100% | 56,492 psi | 89% | 3182 fps | 96.3% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,983 psi | 55% | 1886 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 55,434 psi | 87% | 3077 fps | 99.8% |
| IMR 3031 | <<locked>> | 90% | 56,855 psi | 89% | 3110 fps | 100% |
| IMR 4064 | <<locked>> | 94% | 57,159 psi | 90% | 3091 fps | 99.5% |
| IMR 4166 Enduron | <<locked>> | 90% | 54,360 psi | 85% | 3015 fps | 96.3% |
| IMR 4198 | <<locked>> | 84% | 57,101 psi | 89% | 2976 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 98% | 56,942 psi | 89% | 3084 fps | 96.7% |
| IMR 4831ᴾ | <<locked>> | 100% | 48,791 psi | 76% | 3022 fps | 98.1% |
| IMR 4895 | <<locked>> | 92% | 56,202 psi | 88% | 3136 fps | 99.7% |
| IMR 8208 XBR | <<locked>> | 88% | 55,956 psi | 88% | 3068 fps | 100% |
| Lovex D073.5 | <<locked>> | 84% | 56,159 psi | 88% | 3051 fps | 100% |
| Lovex D073.6 | <<locked>> | 90% | 56,434 psi | 88% | 3091 fps | 100% |
| Lovex S060 | <<locked>> | 90% | 56,681 psi | 89% | 3041 fps | 99.7% |
| Lovex S062 | <<locked>> | 94% | 56,826 psi | 89% | 3087 fps | 100% |
| Lovex S065ᴾ | <<locked>> | 100% | 56,188 psi | 88% | 3081 fps | 98% |
| Lovex S070ᴾ | <<locked>> | 100% | 53,606 psi | 84% | 3058 fps | 96.5% |
| Norma 201 | <<locked>> | 90% | 55,506 psi | 87% | 3058 fps | 100% |
| Norma 202 | <<locked>> | 90% | 55,898 psi | 88% | 3064 fps | 100% |
| Norma 203B | <<locked>> | 94% | 57,566 psi | 90% | 3146 fps | 99.8% |
| Norma URPᴾ | <<locked>> | 100% | 51,155 psi | 80% | 3081 fps | 98.3% |
| Ramshot Big Game | <<locked>> | 92% | 54,230 psi | 85% | 3107 fps | 99.5% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 50,125 psi | 79% | 3068 fps | 96.5% |
| Ramshot TAC | <<locked>> | 88% | 56,710 psi | 89% | 3084 fps | 98.2% |
| Ramshot Wild Boar | <<locked>> | 88% | 55,999 psi | 88% | 3104 fps | 99.6% |
| Ramshot X-Terminator | <<locked>> | 86% | 57,276 psi | 90% | 3071 fps | 99.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,404 psi | 55% | 1932 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 84% | 55,361 psi | 87% | 3048 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 94% | 56,173 psi | 88% | 3081 fps | 97.3% |
| ReloadSwiss RS 52 | <<locked>> | 90% | 54,955 psi | 86% | 3173 fps | 99.3% |
| ReloadSwiss RS 60 | <<locked>> | 96% | 54,389 psi | 85% | 3202 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 51,358 psi | 80% | 3110 fps | 98.2% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 51,634 psi | 81% | 3130 fps | 97.8% |
| Rottweil R 901 | <<locked>> | 88% | 56,347 psi | 88% | 3041 fps | 100% |
| Rottweil R 902 | <<locked>> | 92% | 55,912 psi | 88% | 3054 fps | 100% |
| Rottweil R 903 | <<locked>> | 96% | 54,331 psi | 85% | 3084 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 98% | 54,897 psi | 86% | 3048 fps | 95.8% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 56,188 psi | 88% | 3081 fps | 98% |
| Shooters World Match Rifle | <<locked>> | 90% | 56,434 psi | 88% | 3091 fps | 100% |
| Shooters World Precision | <<locked>> | 94% | 56,826 psi | 89% | 3087 fps | 100% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 53,606 psi | 84% | 3058 fps | 96.5% |
| Shooters World Tactical Rifle | <<locked>> | 82% | 55,245 psi | 87% | 3018 fps | 99.9% |
| SNPE Vectan SP 11 | <<locked>> | 96% | 55,985 psi | 88% | 3143 fps | 99.6% |
| SNPE Vectan SP 3 | <<locked>> | 82% | 54,679 psi | 86% | 2995 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 88% | 54,592 psi | 86% | 3051 fps | 98.3% |
| SNPE Vectan SP 9 | <<locked>> | 90% | 55,332 psi | 87% | 3084 fps | 99.6% |
| SNPE Vectan Tubal 3000 | <<locked>> | 90% | 57,348 psi | 90% | 2999 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 96% | 57,232 psi | 90% | 2992 fps | 100% |
| SNPE Vectan Tubal 7000ᴾ | <<locked>> | 100% | 56,724 psi | 89% | 3025 fps | 96.7% |
| Somchem S321 | <<locked>> | 86% | 57,421 psi | 90% | 3104 fps | 100% |
| Somchem S335 | <<locked>> | 90% | 56,536 psi | 89% | 2995 fps | 100% |
| Somchem S341 | <<locked>> | 88% | 54,346 psi | 85% | 3048 fps | 99.5% |
| Somchem S355 | <<locked>> | 96% | 54,636 psi | 86% | 3081 fps | 99.7% |
| Somchem S365ᴾ | <<locked>> | 100% | 45,527 psi | 71% | 3025 fps | 99.7% |
| Vihtavuori N130 | <<locked>> | 86% | 57,014 psi | 89% | 2966 fps | 100% |
| Vihtavuori N133 | <<locked>> | 90% | 57,377 psi | 90% | 2986 fps | 100% |
| Vihtavuori N135 | <<locked>> | 92% | 55,100 psi | 86% | 3018 fps | 100% |
| Vihtavuori N140 | <<locked>> | 92% | 56,434 psi | 88% | 3038 fps | 100% |
| Vihtavuori N150 | <<locked>> | 98% | 56,521 psi | 89% | 3064 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 53,490 psi | 84% | 3077 fps | 98.6% |
| Vihtavuori N530 | <<locked>> | 88% | 56,550 psi | 89% | 3068 fps | 100% |
| Vihtavuori N540 | <<locked>> | 92% | 54,882 psi | 86% | 3038 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 52,663 psi | 83% | 3084 fps | 98.3% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 38,319 psi | 60% | 2877 fps | 96.1% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 54,534 psi | 85% | 3061 fps | 99.8% |
| Winchester 748 | <<locked>> | 88% | 56,101 psi | 88% | 3117 fps | 100% |
| Winchester 760ᴾ | <<locked>> | 100% | 54,940 psi | 86% | 3143 fps | 96.6% |
| Winchester StaBALL Match | <<locked>> | 90% | 55,230 psi | 87% | 3094 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% | 45,121 psi | 71% | 2822 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 49,211 psi | 77% | 2933 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 37,797 psi | 59% | 2730 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 44,440 psi | 70% | 2884 fps | 99.9% |
| Accurate 4064 | <<locked>> | 80% | 35,694 psi | 56% | 2713 fps | 99.4% |
| Accurate 4350 | <<locked>> | 92% | 39,015 psi | 61% | 2844 fps | 95.5% |
| Accurate LT-30 | <<locked>> | 80% | 53,214 psi | 83% | 2907 fps | 100% |
| Accurate LT-32 | <<locked>> | 80% | 53,606 psi | 84% | 2933 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 41,379 psi | 65% | 2828 fps | 97.5% |
| ADI AR 2208 | <<locked>> | 82% | 37,420 psi | 59% | 2720 fps | 95.6% |
| ADI Benchmark 8208 | <<locked>> | 80% | 43,381 psi | 68% | 2844 fps | 98.9% |
| Alliant AR-Comp | <<locked>> | 80% | 43,221 psi | 68% | 2848 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 50,502 psi | 79% | 3061 fps | 99.5% |
| Alliant Power Pro 2000-MR | 38 gr | 80% | 37,594 psi | 59% | 2841 fps | 95.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 34,447 psi | 54% | 2684 fps | 96.4% |
| Alliant Reloder-10x | <<locked>> | 80% | 50,676 psi | 79% | 2927 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 37,159 psi | 58% | 2753 fps | 95.7% |
| Alliant Reloder-16 | <<locked>> | 92% | 39,160 psi | 61% | 2854 fps | 95.5% |
| Alliant Reloder-17 | <<locked>> | 84% | 34,069 psi | 53% | 2753 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 98% | 33,562 psi | 53% | 2733 fps | 95% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 52,417 psi | 82% | 2897 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 40,393 psi | 63% | 2822 fps | 96.1% |
| Bofors RP3 | <<locked>> | 80% | 34,011 psi | 53% | 2684 fps | 96.4% |
| Bofors RP7 | <<locked>> | 96% | 51,837 psi | 81% | 2995 fps | 95.1% |
| Hodgdon Benchmark | <<locked>> | 80% | 45,411 psi | 71% | 2841 fps | 99.5% |
| Hodgdon BL-C2 | <<locked>> | 80% | 42,134 psi | 66% | 2864 fps | 99.1% |
| Hodgdon CFE223 | <<locked>> | 80% | 46,006 psi | 72% | 3005 fps | 98% |
| Hodgdon H322 | <<locked>> | 80% | 49,690 psi | 78% | 2963 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 50,676 psi | 79% | 2986 fps | 100% |
| Hodgdon H380 | <<locked>> | 84% | 40,001 psi | 63% | 2805 fps | 95.1% |
| Hodgdon H414 | <<locked>> | 96% | 48,124 psi | 75% | 3022 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 41,698 psi | 65% | 2841 fps | 98.1% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 33,750 psi | 53% | 2684 fps | 95.5% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 37,637 psi | 59% | 2802 fps | 97.5% |
| Hodgdon Superformance | <<locked>> | 98% | 52,504 psi | 82% | 3114 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,005 psi | 41% | 1686 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 40,132 psi | 63% | 2792 fps | 97.6% |
| IMR 3031 | <<locked>> | 80% | 40,959 psi | 64% | 2848 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 37,014 psi | 58% | 2703 fps | 95.7% |
| IMR 4166 Enduron | <<locked>> | 88% | 51,053 psi | 80% | 2956 fps | 95.6% |
| IMR 4198 | <<locked>> | 80% | 50,778 psi | 80% | 2887 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 94% | 50,604 psi | 79% | 2979 fps | 95.4% |
| IMR 4831 | <<locked>> | 92% | 37,565 psi | 59% | 2792 fps | 95.1% |
| IMR 4895 | <<locked>> | 80% | 38,043 psi | 60% | 2785 fps | 96.7% |
| IMR 8208 XBR | <<locked>> | 80% | 43,381 psi | 68% | 2844 fps | 98.9% |
| Lovex D073.5 | <<locked>> | 80% | 48,994 psi | 77% | 2936 fps | 99.9% |
| Lovex D073.6 | <<locked>> | 80% | 40,161 psi | 63% | 2808 fps | 99.5% |
| Lovex S060 | <<locked>> | 80% | 41,916 psi | 66% | 2772 fps | 97.6% |
| Lovex S062 | <<locked>> | 80% | 36,912 psi | 58% | 2713 fps | 97.6% |
| Lovex S065 | <<locked>> | 92% | 43,918 psi | 69% | 2858 fps | 95.3% |
| Lovex S070 | <<locked>> | 98% | 50,256 psi | 79% | 2999 fps | 95.7% |
| Norma 201 | <<locked>> | 80% | 40,741 psi | 64% | 2785 fps | 98.5% |
| Norma 202 | <<locked>> | 80% | 40,654 psi | 64% | 2795 fps | 99.8% |
| Norma 203B | <<locked>> | 80% | 36,550 psi | 57% | 2740 fps | 96.1% |
| Norma URP | <<locked>> | 92% | 39,160 psi | 61% | 2841 fps | 95.4% |
| Ramshot Big Game | <<locked>> | 80% | 36,230 psi | 57% | 2749 fps | 95.7% |
| Ramshot Hunter | <<locked>> | 98% | 47,036 psi | 74% | 3009 fps | 95.7% |
| Ramshot TAC | <<locked>> | 80% | 43,381 psi | 68% | 2838 fps | 95.4% |
| Ramshot Wild Boar | <<locked>> | 80% | 42,815 psi | 67% | 2864 fps | 97.8% |
| Ramshot X-Terminator | <<locked>> | 80% | 46,963 psi | 74% | 2894 fps | 98.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,179 psi | 41% | 1726 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 48,689 psi | 76% | 2940 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 46,412 psi | 73% | 2907 fps | 95.1% |
| ReloadSwiss RS 52 | 36.8 gr | 80% | 38,711 psi | 61% | 2854 fps | 96.1% |
| ReloadSwiss RS 60 | 37.4 gr | 80% | 31,908 psi | 50% | 2703 fps | 97.2% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 38,740 psi | 61% | 2858 fps | 95% |
| ReloadSwiss RS 70 | <<locked>> | 94% | 42,206 psi | 66% | 2933 fps | 95.1% |
| Rottweil R 901 | <<locked>> | 80% | 44,309 psi | 69% | 2838 fps | 99.9% |
| Rottweil R 902 | <<locked>> | 80% | 38,798 psi | 61% | 2736 fps | 98% |
| Rottweil R 903 | <<locked>> | 80% | 31,908 psi | 50% | 2621 fps | 95.2% |
| Rottweil R 907 | <<locked>> | 96% | 51,837 psi | 81% | 2995 fps | 95.1% |
| Shooters World Long Rifle | <<locked>> | 92% | 43,918 psi | 69% | 2858 fps | 95.3% |
| Shooters World Match Rifle | <<locked>> | 80% | 40,161 psi | 63% | 2808 fps | 99.5% |
| Shooters World Precision | <<locked>> | 80% | 36,912 psi | 58% | 2713 fps | 97.6% |
| Shooters World SW4350 | <<locked>> | 98% | 50,256 psi | 79% | 2999 fps | 95.7% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 51,779 psi | 81% | 2963 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 35,317 psi | 55% | 2733 fps | 95.5% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 51,532 psi | 81% | 2949 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 41,495 psi | 65% | 2805 fps | 95.5% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 39,987 psi | 63% | 2795 fps | 97.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 42,134 psi | 66% | 2749 fps | 99.9% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 34,809 psi | 55% | 2602 fps | 99.6% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 49,588 psi | 78% | 2910 fps | 95.2% |
| Somchem S321 | <<locked>> | 80% | 46,775 psi | 73% | 2927 fps | 99.5% |
| Somchem S335 | <<locked>> | 80% | 41,829 psi | 66% | 2753 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 41,147 psi | 64% | 2808 fps | 97.3% |
| Somchem S355 | <<locked>> | 80% | 33,127 psi | 52% | 2638 fps | 95.4% |
| Somchem S365 | <<locked>> | 88% | 30,850 psi | 48% | 2667 fps | 95.9% |
| Vihtavuori N130 | <<locked>> | 80% | 47,630 psi | 75% | 2825 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 42,322 psi | 66% | 2746 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 37,811 psi | 59% | 2726 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 38,464 psi | 60% | 2726 fps | 99.7% |
| Vihtavuori N150 | <<locked>> | 80% | 31,227 psi | 49% | 2569 fps | 96.3% |
| Vihtavuori N160 | <<locked>> | 90% | 38,609 psi | 61% | 2789 fps | 95.1% |
| Vihtavuori N530 | <<locked>> | 80% | 43,410 psi | 68% | 2838 fps | 99% |
| Vihtavuori N540 | <<locked>> | 80% | 37,159 psi | 58% | 2713 fps | 99.3% |
| Vihtavuori N550 | <<locked>> | 92% | 40,596 psi | 64% | 2851 fps | 95.6% |
| Vihtavuori N555 | <<locked>> | 98% | 35,839 psi | 56% | 2815 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 34,127 psi | 53% | 2651 fps | 95.8% |
| Winchester 748 | <<locked>> | 80% | 42,815 psi | 67% | 2887 fps | 99.4% |
| Winchester 760 | <<locked>> | 96% | 48,124 psi | 75% | 3022 fps | 95% |
| Winchester StaBALL Match | <<locked>> | 80% | 39,407 psi | 62% | 2799 fps | 97.6% |
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 102 powders for .25 WSSM loaded with the .257 | 100gr | Swift Scirocco. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,235 fps; across all powders the maximum-charge window runs from 1,886 fps to 3,235 fps. Accurate 4350 gives the best case fill at 100 %, and 102 of the 102 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 55–90 %, leaving at least 10 % headroom. The 100.0 gr projectile in 0.257" calls for a 1:9.5 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 Power Pro 2000-MR, ReloadSwiss RS 52 rank at the top here: for .25 WSSM with the .257 | 100gr | Swift Scirocco 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.