Load Specifications
Load data in caliber .255 GS with .257 | 120gr | Speer Spitzer Soft Point bullet and 96 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-26 and Ramshot Grand.
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.
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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>> | 82% | 55,666 psi | 87% | 2808 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 54,259 psi | 85% | 2831 fps | 98.6% |
| Accurate 3100ᴾ | <<locked>> | 100% | 55,230 psi | 87% | 2922 fps | 99.6% |
| Accurate 4064 | <<locked>> | 84% | 55,999 psi | 88% | 2867 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 56,739 psi | 89% | 2972 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 55,999 psi | 88% | 2898 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 54,244 psi | 85% | 2964 fps | 98% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 56,391 psi | 88% | 3012 fps | 97% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 55,288 psi | 87% | 3022 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 56,927 psi | 89% | 2922 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 56,855 psi | 89% | 2940 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 57,450 psi | 90% | 3030 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 55,114 psi | 86% | 3002 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 57,435 psi | 90% | 3008 fps | 98.5% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 55,535 psi | 87% | 3008 fps | 98.2% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 52,895 psi | 83% | 2941 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,686 psi | 70% | 2862 fps | 99.1% |
| Alliant Reloder-26 | <<locked>> | 98% | 55,056 psi | 86% | 3080 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 49,617 psi | 78% | 2927 fps | 97.2% |
| Bofors RP3 | <<locked>> | 84% | 54,012 psi | 85% | 2885 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 54,360 psi | 85% | 3009 fps | 98.2% |
| Bofors RP7 | <<locked>> | 90% | 56,927 psi | 89% | 2923 fps | 99.1% |
| Hodgdon H380 | <<locked>> | 84% | 54,433 psi | 85% | 2901 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 88% | 56,608 psi | 89% | 2993 fps | 99.4% |
| Hodgdon H4350 | <<locked>> | 92% | 56,884 psi | 89% | 2959 fps | 98.6% |
| Hodgdon H4831 SC | <<locked>> | 98% | 54,273 psi | 85% | 2935 fps | 96.1% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 54,331 psi | 85% | 2903 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 56,014 psi | 88% | 2943 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 43,700 psi | 68% | 2890 fps | 96.4% |
| Hodgdon Superformance | <<locked>> | 90% | 55,506 psi | 87% | 3009 fps | 99.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,333 psi | 59% | 1814 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 55,463 psi | 87% | 2887 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 54,897 psi | 86% | 2858 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 54,868 psi | 86% | 2871 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 88% | 57,058 psi | 89% | 2902 fps | 99.4% |
| IMR 4350 | <<locked>> | 92% | 54,621 psi | 86% | 2907 fps | 98.8% |
| IMR 4451 Enduron | <<locked>> | 88% | 55,187 psi | 86% | 2897 fps | 99.2% |
| IMR 4831 | <<locked>> | 96% | 54,563 psi | 86% | 2927 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 54,897 psi | 86% | 2918 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 57,087 psi | 89% | 2943 fps | 96.9% |
| IMR 7828 SSC | <<locked>> | 98% | 53,577 psi | 84% | 2992 fps | 96.7% |
| Lovex S060 | <<locked>> | 82% | 56,724 psi | 89% | 2862 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 55,782 psi | 87% | 2876 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 55,390 psi | 87% | 2896 fps | 99.8% |
| Lovex S070 | <<locked>> | 92% | 56,579 psi | 89% | 2937 fps | 99.5% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,948 psi | 72% | 2771 fps | 98.5% |
| Norma 201 | <<locked>> | 82% | 57,014 psi | 89% | 2885 fps | 100% |
| Norma 202 | <<locked>> | 82% | 57,638 psi | 90% | 2878 fps | 100% |
| Norma 203B | <<locked>> | 84% | 56,144 psi | 88% | 2926 fps | 100% |
| Norma 204 | <<locked>> | 92% | 55,245 psi | 87% | 2956 fps | 98% |
| Norma MRP | <<locked>> | 98% | 54,868 psi | 86% | 3033 fps | 99.2% |
| Norma URP | <<locked>> | 92% | 55,376 psi | 87% | 2959 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 57,130 psi | 90% | 2956 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 52,678 psi | 83% | 2990 fps | 96.9% |
| Ramshot Hunter | <<locked>> | 92% | 54,186 psi | 85% | 2958 fps | 99.6% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 54,491 psi | 85% | 2975 fps | 98.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,434 psi | 59% | 1860 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 54,302 psi | 85% | 2885 fps | 99.4% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 54,607 psi | 86% | 2992 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 56,579 psi | 89% | 2996 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 55,245 psi | 87% | 3028 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,976 psi | 69% | 2885 fps | 97.5% |
| Rottweil R 902 | <<locked>> | 84% | 57,740 psi | 90% | 2886 fps | 100% |
| Rottweil R 903 | <<locked>> | 88% | 57,696 psi | 90% | 2932 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 55,753 psi | 87% | 2931 fps | 97.2% |
| Rottweil R 905 | <<locked>> | 98% | 57,566 psi | 90% | 2993 fps | 98.5% |
| Rottweil R 907 | <<locked>> | 90% | 56,927 psi | 89% | 2923 fps | 99.1% |
| Shooters World Long Rifle | <<locked>> | 90% | 55,390 psi | 87% | 2896 fps | 99.8% |
| Shooters World Precision | <<locked>> | 84% | 55,782 psi | 87% | 2876 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 56,579 psi | 89% | 2936 fps | 99.5% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 55,912 psi | 88% | 2944 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 56,695 psi | 89% | 2914 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 57,740 psi | 90% | 2812 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 55,013 psi | 86% | 2765 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 54,998 psi | 86% | 2846 fps | 99.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 55,898 psi | 88% | 2989 fps | 98.4% |
| Somchem S335 | <<locked>> | 82% | 57,421 psi | 90% | 2809 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 57,522 psi | 90% | 2925 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 57,667 psi | 90% | 2925 fps | 96.7% |
| Somchem S365 | <<locked>> | 94% | 54,737 psi | 86% | 2960 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 56,884 psi | 89% | 2966 fps | 99.1% |
| Unknown powder | <<locked>> | 90% | 56,057 psi | 88% | 2965 fps | 100% |
| Vihtavuori N133 | <<locked>> | 84% | 57,638 psi | 90% | 2788 fps | 100% |
| Vihtavuori N135 | <<locked>> | 82% | 54,650 psi | 86% | 2795 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 57,493 psi | 90% | 2849 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 55,767 psi | 87% | 2859 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 56,608 psi | 89% | 2935 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 50,662 psi | 79% | 2852 fps | 97.9% |
| Vihtavuori N540 | <<locked>> | 84% | 57,072 psi | 89% | 2874 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 56,855 psi | 89% | 2981 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 54,244 psi | 85% | 2969 fps | 100% |
| Vihtavuori N560ᴾ | <<locked>> | 100% | 55,085 psi | 86% | 3035 fps | 96.6% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 57,348 psi | 90% | 2919 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 56,608 psi | 89% | 2993 fps | 99.4% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,775 psi | 73% | 2999 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 55,361 psi | 87% | 2935 fps | 98.1% |
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% | 51,938 psi | 81% | 2759 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 44,817 psi | 70% | 2667 fps | 96.8% |
| Accurate 3100 | <<locked>> | 86% | 33,968 psi | 53% | 2527 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 49,240 psi | 77% | 2766 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 37,797 psi | 59% | 2635 fps | 98.2% |
| ADI AR 2208 | <<locked>> | 80% | 46,427 psi | 73% | 2740 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 90% | 44,382 psi | 70% | 2781 fps | 95.7% |
| ADI AR 2213 | <<locked>> | 96% | 48,530 psi | 76% | 2888 fps | 95.3% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 51,532 psi | 81% | 2960 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,123 psi | 74% | 2768 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,343 psi | 79% | 2837 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,767 psi | 58% | 2642 fps | 98.3% |
| Alliant Reloder-17 | <<locked>> | 80% | 41,597 psi | 65% | 2767 fps | 99.9% |
| Alliant Reloder-19 | <<locked>> | 90% | 44,106 psi | 69% | 2776 fps | 95.8% |
| Alliant Reloder-22 | <<locked>> | 92% | 41,698 psi | 65% | 2770 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 26,847 psi | 42% | 2386 fps | 95.8% |
| Alliant Reloder-25 | <<locked>> | 90% | 32,445 psi | 51% | 2564 fps | 95% |
| Alliant Reloder-26 | 46.1 gr | 82% | 30,734 psi | 48% | 2558 fps | 95.2% |
| Bofors RP15 | <<locked>> | 96% | 43,787 psi | 69% | 2815 fps | 95.7% |
| Bofors RP3 | <<locked>> | 80% | 47,384 psi | 74% | 2778 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 41,698 psi | 65% | 2769 fps | 95.2% |
| Bofors RP7 | <<locked>> | 80% | 41,742 psi | 65% | 2649 fps | 96.2% |
| Hodgdon H380 | <<locked>> | 80% | 47,848 psi | 75% | 2790 fps | 99.5% |
| Hodgdon H414 | <<locked>> | 80% | 43,120 psi | 68% | 2751 fps | 97.2% |
| Hodgdon H4350 | <<locked>> | 82% | 41,727 psi | 65% | 2680 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 96% | 50,923 psi | 80% | 2878 fps | 95.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,243 psi | 54% | 2534 fps | 98.8% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 49,240 psi | 77% | 2835 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 40,843 psi | 64% | 2822 fps | 95.2% |
| Hodgdon Superformance | <<locked>> | 80% | 38,537 psi | 60% | 2685 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,224 psi | 43% | 1622 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 49,066 psi | 77% | 2785 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 51,474 psi | 81% | 2809 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 45,585 psi | 71% | 2717 fps | 99.8% |
| IMR 4166 Enduron | <<locked>> | 80% | 44,889 psi | 70% | 2690 fps | 97.5% |
| IMR 4350 | <<locked>> | 82% | 39,871 psi | 62% | 2628 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,192 psi | 68% | 2680 fps | 97% |
| IMR 4831 | <<locked>> | 80% | 32,909 psi | 52% | 2503 fps | 96.8% |
| IMR 4895 | <<locked>> | 80% | 51,634 psi | 81% | 2865 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 50,328 psi | 79% | 2831 fps | 95.4% |
| IMR 7828 SSC | <<locked>> | 96% | 49,690 psi | 78% | 2925 fps | 95.8% |
| Lovex S060 | <<locked>> | 80% | 53,447 psi | 84% | 2813 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,110 psi | 77% | 2772 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 40,495 psi | 63% | 2625 fps | 97.7% |
| Lovex S070 | <<locked>> | 80% | 38,870 psi | 61% | 2607 fps | 96.1% |
| Lovex S071 | <<locked>> | 92% | 35,070 psi | 55% | 2555 fps | 95.8% |
| Norma 201 | <<locked>> | 80% | 53,345 psi | 84% | 2830 fps | 100% |
| Norma 202 | <<locked>> | 80% | 54,244 psi | 85% | 2831 fps | 100% |
| Norma 203B | <<locked>> | 80% | 49,690 psi | 78% | 2824 fps | 100% |
| Norma 204 | <<locked>> | 86% | 45,165 psi | 71% | 2777 fps | 95.8% |
| Norma MRP | <<locked>> | 88% | 38,014 psi | 60% | 2718 fps | 95.4% |
| Norma URP | <<locked>> | 80% | 37,463 psi | 59% | 2626 fps | 98% |
| Ramshot Big Game | <<locked>> | 80% | 50,009 psi | 78% | 2845 fps | 100% |
| Ramshot Grand | 52.9 gr | 94% | 48,950 psi | 77% | 2921 fps | 96% |
| Ramshot Hunter | <<locked>> | 80% | 36,245 psi | 57% | 2608 fps | 96% |
| Ramshot Magnum | <<locked>> | 92% | 39,436 psi | 62% | 2705 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,804 psi | 44% | 1663 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 47,601 psi | 75% | 2770 fps | 98.6% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,179 psi | 69% | 2822 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,507 psi | 59% | 2650 fps | 97.9% |
| ReloadSwiss RS 70 | 44.6 gr | 80% | 36,347 psi | 57% | 2652 fps | 97.2% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 37,840 psi | 59% | 2740 fps | 95.1% |
| Rottweil R 902 | <<locked>> | 80% | 51,111 psi | 80% | 2787 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 44,643 psi | 70% | 2724 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 49,255 psi | 77% | 2821 fps | 95.8% |
| Rottweil R 905 | <<locked>> | 90% | 43,062 psi | 67% | 2757 fps | 95.6% |
| Rottweil R 907 | <<locked>> | 80% | 41,742 psi | 65% | 2649 fps | 96.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,495 psi | 63% | 2625 fps | 97.7% |
| Shooters World Precision | <<locked>> | 80% | 49,110 psi | 77% | 2772 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 38,870 psi | 61% | 2608 fps | 96.1% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,672 psi | 72% | 2777 fps | 99.9% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 53,113 psi | 83% | 2860 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 54,244 psi | 85% | 2765 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 45,934 psi | 72% | 2632 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 39,639 psi | 62% | 2569 fps | 96.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 42,714 psi | 67% | 2753 fps | 95.5% |
| Somchem S335 | <<locked>> | 80% | 53,809 psi | 84% | 2758 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 44,802 psi | 70% | 2721 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 50,604 psi | 79% | 2812 fps | 95.2% |
| Somchem S365 | <<locked>> | 80% | 33,837 psi | 53% | 2579 fps | 99.6% |
| Somchem S385 | <<locked>> | 86% | 38,493 psi | 60% | 2629 fps | 95.1% |
| Unknown powder | <<locked>> | 80% | 40,480 psi | 63% | 2685 fps | 98.2% |
| Vihtavuori N133 | <<locked>> | 80% | 51,285 psi | 80% | 2700 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 51,329 psi | 80% | 2749 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 50,633 psi | 79% | 2752 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 38,580 psi | 60% | 2570 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 80% | 40,379 psi | 63% | 2654 fps | 98.6% |
| Vihtavuori N165 | <<locked>> | 94% | 41,597 psi | 65% | 2686 fps | 95.7% |
| Vihtavuori N540 | <<locked>> | 80% | 50,357 psi | 79% | 2777 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,089 psi | 64% | 2701 fps | 98.7% |
| Vihtavuori N555 | <<locked>> | 80% | 29,588 psi | 46% | 2465 fps | 96% |
| Vihtavuori N560 | <<locked>> | 98% | 52,040 psi | 82% | 2971 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 37,884 psi | 59% | 2592 fps | 99.6% |
| Winchester 760 | <<locked>> | 80% | 43,120 psi | 68% | 2751 fps | 97.2% |
| Winchester StaBALL HD | <<locked>> | 82% | 25,396 psi | 40% | 2414 fps | 95.5% |
| Winchester Supreme 780 | <<locked>> | 90% | 44,353 psi | 70% | 2746 fps | 95.8% |
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 104 powders for .255 GS loaded with the .257 | 120gr | Speer Spitzer Soft Point. Alliant Reloder-26 delivers the highest muzzle velocity at 3,080 fps; across all powders the maximum-charge window runs from 1,814 fps to 3,080 fps. Accurate 3100 gives the best case fill at 100 %, and 104 of the 104 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 2213 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-26, Ramshot Grand rank at the top here: for .255 GS 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 2217, ADI AR 2225 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.