Load Specifications
Load data in caliber .255 GS with .257 | 115gr | Barnes XLC S bullet and 96 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, ReloadSwiss RS 70 and Alliant Reloder-16.
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 2495 | <<locked>> | 82% | 56,869 psi | 89% | 2854 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 57,682 psi | 90% | 2907 fps | 98.5% |
| Accurate 3100ᴾ | <<locked>> | 100% | 54,723 psi | 86% | 2953 fps | 99.3% |
| Accurate 4064 | <<locked>> | 84% | 57,029 psi | 89% | 2910 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 56,652 psi | 89% | 3005 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 55,448 psi | 87% | 2920 fps | 100% |
| ADI AR 2209 | <<locked>> | 98% | 56,782 psi | 89% | 3031 fps | 97.7% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 54,476 psi | 85% | 3018 fps | 95.9% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 54,520 psi | 85% | 3045 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 56,579 psi | 89% | 2949 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 56,797 psi | 89% | 2972 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 56,463 psi | 88% | 3051 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 54,259 psi | 85% | 3028 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 56,275 psi | 88% | 3022 fps | 97.8% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 53,403 psi | 84% | 3025 fps | 97.4% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 50,734 psi | 80% | 2966 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,498 psi | 70% | 2884 fps | 98.5% |
| Alliant Reloder-26 | <<locked>> | 98% | 54,114 psi | 85% | 3104 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 57,696 psi | 90% | 2986 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 49,240 psi | 77% | 2946 fps | 96.3% |
| Bofors RP3 | <<locked>> | 84% | 54,534 psi | 85% | 2923 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 53,403 psi | 84% | 3025 fps | 97.4% |
| Bofors RP7 | <<locked>> | 90% | 56,869 psi | 89% | 2946 fps | 98.6% |
| Hodgdon H380 | <<locked>> | 84% | 54,418 psi | 85% | 2930 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 88% | 56,014 psi | 88% | 3015 fps | 98.9% |
| Hodgdon H4350 | <<locked>> | 92% | 56,159 psi | 88% | 2976 fps | 97.9% |
| Hodgdon H4831 SCᴾ | <<locked>> | 100% | 57,087 psi | 89% | 3005 fps | 95.8% |
| Hodgdon Hybrid 100V | <<locked>> | 96% | 57,087 psi | 89% | 2976 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 55,448 psi | 87% | 2969 fps | 100% |
| Hodgdon Superformance | <<locked>> | 90% | 54,592 psi | 86% | 3025 fps | 98.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,651 psi | 57% | 1837 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 55,056 psi | 86% | 2913 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 54,839 psi | 86% | 2894 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 54,636 psi | 86% | 2897 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 88% | 56,536 psi | 89% | 2920 fps | 98.9% |
| IMR 4350 | <<locked>> | 94% | 57,363 psi | 90% | 2976 fps | 98.7% |
| IMR 4451 Enduron | <<locked>> | 88% | 54,752 psi | 86% | 2917 fps | 98.6% |
| IMR 4831 | <<locked>> | 98% | 57,711 psi | 90% | 3005 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 54,853 psi | 86% | 2949 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 56,318 psi | 88% | 2956 fps | 95.9% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 55,883 psi | 88% | 3058 fps | 96.4% |
| Lovex S060 | <<locked>> | 82% | 56,710 psi | 89% | 2890 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 55,637 psi | 87% | 2904 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 55,143 psi | 86% | 2917 fps | 99.5% |
| Lovex S070 | <<locked>> | 92% | 56,391 psi | 88% | 2959 fps | 99% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,818 psi | 72% | 2802 fps | 98% |
| Norma 201 | <<locked>> | 82% | 57,232 psi | 90% | 2917 fps | 100% |
| Norma 202 | <<locked>> | 82% | 57,522 psi | 90% | 2910 fps | 100% |
| Norma 203B | <<locked>> | 84% | 56,159 psi | 88% | 2959 fps | 100% |
| Norma 204 | <<locked>> | 92% | 54,346 psi | 85% | 2969 fps | 97.2% |
| Norma MRPᴾ | <<locked>> | 100% | 56,797 psi | 89% | 3114 fps | 99.1% |
| Norma URP | <<locked>> | 92% | 54,824 psi | 86% | 2982 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 84% | 56,724 psi | 89% | 2982 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 55,782 psi | 87% | 3064 fps | 96.7% |
| Ramshot Hunter | <<locked>> | 94% | 57,116 psi | 90% | 3038 fps | 99.5% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 52,736 psi | 83% | 2982 fps | 97.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,318 psi | 58% | 1877 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 54,201 psi | 85% | 2907 fps | 99% |
| ReloadSwiss RS 52 | <<locked>> | 82% | 57,522 psi | 90% | 3038 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 88% | 57,435 psi | 90% | 3074 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 56,275 psi | 88% | 3025 fps | 99.9% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 54,433 psi | 85% | 3048 fps | 99.9% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,569 psi | 68% | 2897 fps | 96.4% |
| Rottweil R 902 | <<locked>> | 82% | 54,636 psi | 86% | 2871 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 54,375 psi | 85% | 2913 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 55,245 psi | 87% | 2949 fps | 96.3% |
| Rottweil R 905 | <<locked>> | 98% | 55,535 psi | 87% | 3009 fps | 97.8% |
| Rottweil R 907 | <<locked>> | 90% | 56,869 psi | 89% | 2946 fps | 98.6% |
| Shooters World Long Rifle | <<locked>> | 90% | 55,143 psi | 86% | 2917 fps | 99.5% |
| Shooters World Precision | <<locked>> | 84% | 55,637 psi | 87% | 2904 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 56,391 psi | 88% | 2959 fps | 99% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 55,216 psi | 87% | 2966 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 56,260 psi | 88% | 2940 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 57,392 psi | 90% | 2838 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 54,795 psi | 86% | 2795 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 54,810 psi | 86% | 2867 fps | 98.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 55,027 psi | 86% | 3002 fps | 97.6% |
| Somchem S335 | <<locked>> | 82% | 57,537 psi | 90% | 2841 fps | 100% |
| Somchem S355 | <<locked>> | 86% | 54,462 psi | 85% | 2910 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 56,985 psi | 89% | 2940 fps | 95.8% |
| Somchem S365 | <<locked>> | 96% | 57,667 psi | 90% | 3038 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 56,463 psi | 88% | 2989 fps | 98.5% |
| Unknown powder | <<locked>> | 90% | 55,332 psi | 87% | 2986 fps | 99.8% |
| Vihtavuori N133 | <<locked>> | 84% | 57,435 psi | 90% | 2818 fps | 100% |
| Vihtavuori N135 | <<locked>> | 82% | 54,563 psi | 86% | 2825 fps | 100% |
| Vihtavuori N140 | <<locked>> | 84% | 57,348 psi | 90% | 2881 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 55,593 psi | 87% | 2887 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 56,028 psi | 88% | 2956 fps | 99.9% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 50,198 psi | 79% | 2871 fps | 97.1% |
| Vihtavuori N540 | <<locked>> | 84% | 57,188 psi | 90% | 2910 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 56,420 psi | 88% | 3005 fps | 99.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 56,927 psi | 89% | 3048 fps | 100% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 56,507 psi | 89% | 2943 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 56,014 psi | 88% | 3015 fps | 98.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,064 psi | 72% | 3025 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 54,433 psi | 85% | 2946 fps | 97.3% |
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% | 53,563 psi | 84% | 2808 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 45,078 psi | 71% | 2690 fps | 96.1% |
| Accurate 3100 | <<locked>> | 86% | 35,128 psi | 55% | 2575 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 50,676 psi | 79% | 2815 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,725 psi | 61% | 2677 fps | 97.9% |
| ADI AR 2208 | <<locked>> | 80% | 46,586 psi | 73% | 2769 fps | 99.6% |
| ADI AR 2209 | <<locked>> | 92% | 47,224 psi | 74% | 2861 fps | 95.6% |
| ADI AR 2213 | <<locked>> | 98% | 51,213 psi | 80% | 2959 fps | 95.1% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 50,923 psi | 80% | 2982 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,311 psi | 74% | 2799 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,401 psi | 79% | 2867 fps | 99.9% |
| Alliant Reloder-16 | 39.3 gr | 80% | 37,043 psi | 58% | 2671 fps | 97.7% |
| Alliant Reloder-17 | <<locked>> | 80% | 41,843 psi | 66% | 2802 fps | 99.8% |
| Alliant Reloder-19 | <<locked>> | 92% | 46,659 psi | 73% | 2851 fps | 95.6% |
| Alliant Reloder-22 | <<locked>> | 94% | 44,425 psi | 70% | 2854 fps | 95.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 28,065 psi | 44% | 2438 fps | 95.6% |
| Alliant Reloder-25 | <<locked>> | 92% | 35,244 psi | 55% | 2657 fps | 95.4% |
| Alliant Reloder-26 | 45.6 gr | 84% | 33,895 psi | 53% | 2667 fps | 95.9% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 54,389 psi | 85% | 2933 fps | 99.9% |
| Bofors RP15 | <<locked>> | 98% | 46,311 psi | 73% | 2887 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 47,964 psi | 75% | 2815 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 44,425 psi | 70% | 2854 fps | 95.2% |
| Bofors RP7 | <<locked>> | 80% | 42,206 psi | 66% | 2677 fps | 95.5% |
| Hodgdon H380 | <<locked>> | 80% | 48,240 psi | 76% | 2822 fps | 99.2% |
| Hodgdon H414 | <<locked>> | 80% | 43,134 psi | 68% | 2779 fps | 96.5% |
| Hodgdon H4350 | <<locked>> | 84% | 44,498 psi | 70% | 2762 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 98% | 53,606 psi | 84% | 2946 fps | 95% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,940 psi | 55% | 2572 fps | 98.5% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 49,066 psi | 77% | 2867 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 41,611 psi | 65% | 2772 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,528 psi | 43% | 1640 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 49,124 psi | 77% | 2815 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 51,445 psi | 81% | 2844 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 45,847 psi | 72% | 2746 fps | 99.6% |
| IMR 4166 Enduron | <<locked>> | 80% | 45,165 psi | 71% | 2713 fps | 96.9% |
| IMR 4350 | <<locked>> | 84% | 42,641 psi | 67% | 2710 fps | 95.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,294 psi | 68% | 2703 fps | 96.3% |
| IMR 4831 | <<locked>> | 80% | 33,895 psi | 53% | 2546 fps | 96.5% |
| IMR 4895 | <<locked>> | 80% | 51,706 psi | 81% | 2897 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 53,113 psi | 83% | 2904 fps | 95.2% |
| IMR 7828 SSC | <<locked>> | 98% | 52,431 psi | 82% | 2995 fps | 95.5% |
| Lovex S060 | <<locked>> | 80% | 53,432 psi | 84% | 2841 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,647 psi | 78% | 2808 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,379 psi | 65% | 2664 fps | 97.3% |
| Lovex S070 | <<locked>> | 80% | 39,610 psi | 62% | 2641 fps | 95.6% |
| Lovex S071 | <<locked>> | 92% | 36,187 psi | 57% | 2602 fps | 95.4% |
| Norma 201 | <<locked>> | 80% | 53,969 psi | 85% | 2867 fps | 100% |
| Norma 202 | <<locked>> | 80% | 54,172 psi | 85% | 2861 fps | 100% |
| Norma 203B | <<locked>> | 80% | 49,806 psi | 78% | 2854 fps | 100% |
| Norma 204 | <<locked>> | 88% | 48,008 psi | 75% | 2854 fps | 95.7% |
| Norma MRP | <<locked>> | 90% | 40,988 psi | 64% | 2812 fps | 95.6% |
| Norma URP | <<locked>> | 80% | 37,913 psi | 59% | 2657 fps | 97.6% |
| Ramshot Big Game | <<locked>> | 80% | 49,676 psi | 78% | 2871 fps | 99.9% |
| Ramshot Grand | <<locked>> | 96% | 51,982 psi | 81% | 2995 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 36,767 psi | 58% | 2641 fps | 95.4% |
| Ramshot Magnum | <<locked>> | 94% | 42,641 psi | 67% | 2792 fps | 95.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,166 psi | 44% | 1683 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 47,892 psi | 75% | 2799 fps | 98.1% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 54,070 psi | 85% | 2986 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,251 psi | 69% | 2858 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,898 psi | 59% | 2684 fps | 97.4% |
| ReloadSwiss RS 70 | 43 gr | 80% | 36,782 psi | 58% | 2680 fps | 96.5% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 40,799 psi | 64% | 2828 fps | 95.2% |
| Rottweil R 902 | <<locked>> | 80% | 51,459 psi | 81% | 2818 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 45,281 psi | 71% | 2759 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 94% | 51,982 psi | 81% | 2890 fps | 95.6% |
| Rottweil R 905 | <<locked>> | 92% | 46,021 psi | 72% | 2841 fps | 95.7% |
| Rottweil R 907 | <<locked>> | 80% | 42,206 psi | 66% | 2677 fps | 95.5% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,379 psi | 65% | 2664 fps | 97.3% |
| Shooters World Precision | <<locked>> | 80% | 49,647 psi | 78% | 2808 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 39,610 psi | 62% | 2641 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,774 psi | 72% | 2805 fps | 99.7% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 53,011 psi | 83% | 2890 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 54,317 psi | 85% | 2795 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,122 psi | 72% | 2661 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,640 psi | 64% | 2605 fps | 95.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 45,585 psi | 71% | 2835 fps | 95.5% |
| Somchem S335 | <<locked>> | 80% | 54,244 psi | 85% | 2795 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 45,469 psi | 71% | 2759 fps | 99.9% |
| Somchem S361 | <<locked>> | 94% | 53,403 psi | 84% | 2881 fps | 95% |
| Somchem S365 | <<locked>> | 80% | 34,708 psi | 54% | 2625 fps | 99.4% |
| Somchem S385 | <<locked>> | 88% | 41,481 psi | 65% | 2713 fps | 95.3% |
| Unknown powder | <<locked>> | 80% | 40,683 psi | 64% | 2713 fps | 97.7% |
| Vihtavuori N133 | <<locked>> | 80% | 51,503 psi | 81% | 2736 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 51,605 psi | 81% | 2785 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 50,865 psi | 80% | 2785 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 39,291 psi | 62% | 2608 fps | 99.8% |
| Vihtavuori N160 | <<locked>> | 80% | 40,727 psi | 64% | 2687 fps | 98.2% |
| Vihtavuori N165 | <<locked>> | 96% | 44,367 psi | 70% | 2762 fps | 95.7% |
| Vihtavuori N540 | <<locked>> | 80% | 50,517 psi | 79% | 2808 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,597 psi | 65% | 2736 fps | 98.3% |
| Vihtavuori N555 | <<locked>> | 80% | 30,821 psi | 48% | 2523 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,435 psi | 60% | 2628 fps | 99.4% |
| Winchester 760 | <<locked>> | 80% | 43,134 psi | 68% | 2779 fps | 96.5% |
| Winchester StaBALL HD | <<locked>> | 82% | 26,643 psi | 42% | 2467 fps | 95.3% |
| Winchester Supreme 780 | <<locked>> | 92% | 47,543 psi | 75% | 2828 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 105 powders for .255 GS loaded with the .257 | 115gr | Barnes XLC S. Norma MRP delivers the highest muzzle velocity at 3,114 fps; across all powders the maximum-charge window runs from 1,837 fps to 3,114 fps. Accurate 3100 gives the best case fill at 100 %, and 105 of the 105 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 115.0 gr projectile in 0.257" calls for a 1:9.5 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. Alliant Reloder-26, ReloadSwiss RS 70, Alliant Reloder-16 rank at the top here: for .255 GS with the .257 | 115gr | Barnes XLC S they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate MAGPRO, ADI AR 2225, Baschieri & Pellagri 109 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.