Load Specifications
Load data in caliber .255 GS with .257 | 90gr | Reichenberg HDB Universal bullet and 95 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Power Pro 2000-MR, ReloadSwiss RS 60 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>> | 84% | 56,260 psi | 88% | 3199 fps | 100% |
| Accurate 2495 | <<locked>> | 84% | 54,012 psi | 85% | 3232 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 55,071 psi | 86% | 3268 fps | 100% |
| Accurate 2700 | <<locked>> | 92% | 55,506 psi | 87% | 3205 fps | 96% |
| Accurate 4064 | <<locked>> | 90% | 55,027 psi | 86% | 3264 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 55,216 psi | 87% | 3343 fps | 99.1% |
| ADI AR 2206H | <<locked>> | 86% | 55,492 psi | 87% | 3301 fps | 99.7% |
| ADI AR 2208 | <<locked>> | 92% | 56,376 psi | 88% | 3294 fps | 99.5% |
| ADI Benchmark 8208 | <<locked>> | 84% | 54,259 psi | 85% | 3245 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 84% | 54,955 psi | 86% | 3225 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 55,303 psi | 87% | 3422 fps | 99.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 56,739 psi | 89% | 3323 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 57,188 psi | 90% | 3346 fps | 99.6% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 56,289 psi | 88% | 3409 fps | 99.5% |
| Alliant Reloder-17 | <<locked>> | 94% | 54,230 psi | 85% | 3392 fps | 99.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 40,582 psi | 64% | 3094 fps | 97.9% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 45,672 psi | 72% | 3274 fps | 97.2% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 55,201 psi | 87% | 3304 fps | 99.1% |
| Bofors RP3 | <<locked>> | 92% | 57,566 psi | 90% | 3340 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 57,261 psi | 90% | 3294 fps | 96.6% |
| Hodgdon Benchmark | <<locked>> | 84% | 55,796 psi | 87% | 3228 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 57,450 psi | 90% | 3333 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 55,840 psi | 88% | 3386 fps | 99.5% |
| Hodgdon H322 | <<locked>> | 84% | 57,696 psi | 90% | 3291 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 54,621 psi | 86% | 3287 fps | 98.6% |
| Hodgdon H414 | <<locked>> | 94% | 56,159 psi | 88% | 3366 fps | 97.1% |
| Hodgdon H4895 | <<locked>> | 86% | 56,028 psi | 88% | 3314 fps | 99.9% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 52,736 psi | 83% | 3271 fps | 99.7% |
| Hodgdon LEVERevolution | <<locked>> | 90% | 55,564 psi | 87% | 3343 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 55,274 psi | 87% | 3369 fps | 96.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,360 psi | 55% | 2073 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 55,898 psi | 88% | 3294 fps | 99.9% |
| IMR 3031 | <<locked>> | 88% | 54,375 psi | 85% | 3274 fps | 100% |
| IMR 4064 | <<locked>> | 92% | 54,940 psi | 86% | 3261 fps | 99.4% |
| IMR 4166 Enduron | <<locked>> | 92% | 54,563 psi | 86% | 3228 fps | 96.6% |
| IMR 4350 | <<locked>> | 98% | 54,418 psi | 85% | 3264 fps | 96.1% |
| IMR 4451 Enduron | <<locked>> | 94% | 55,695 psi | 87% | 3271 fps | 96.8% |
| IMR 4831ᴾ | <<locked>> | 100% | 49,719 psi | 78% | 3225 fps | 98.3% |
| IMR 4895 | <<locked>> | 88% | 54,882 psi | 86% | 3317 fps | 99.7% |
| IMR 8208 XBR | <<locked>> | 84% | 54,259 psi | 85% | 3245 fps | 99.9% |
| Lovex D073.6 | <<locked>> | 86% | 55,448 psi | 87% | 3274 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 54,708 psi | 86% | 3219 fps | 99.6% |
| Lovex S062 | <<locked>> | 90% | 55,811 psi | 87% | 3278 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 55,303 psi | 87% | 3271 fps | 98.1% |
| Lovex S070 | <<locked>> | 98% | 56,376 psi | 88% | 3307 fps | 97.3% |
| Norma 201 | <<locked>> | 88% | 57,551 psi | 90% | 3297 fps | 100% |
| Norma 202 | <<locked>> | 86% | 54,578 psi | 86% | 3245 fps | 100% |
| Norma 203B | <<locked>> | 90% | 56,391 psi | 88% | 3333 fps | 99.8% |
| Norma URP | <<locked>> | 98% | 54,346 psi | 85% | 3330 fps | 98.9% |
| Ramshot Big Game | <<locked>> | 90% | 57,217 psi | 90% | 3356 fps | 99.8% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 56,782 psi | 89% | 3383 fps | 98% |
| Ramshot TAC | <<locked>> | 84% | 54,665 psi | 86% | 3255 fps | 98.1% |
| Ramshot Wild Boar | <<locked>> | 84% | 54,433 psi | 85% | 3281 fps | 99.6% |
| Ramshot X-Terminator | <<locked>> | 82% | 55,187 psi | 86% | 3241 fps | 99.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,969 psi | 56% | 2123 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 57,174 psi | 90% | 3284 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 54,940 psi | 86% | 3264 fps | 97.3% |
| ReloadSwiss RS 52 | <<locked>> | 88% | 57,696 psi | 90% | 3419 fps | 99.6% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 53,635 psi | 84% | 3392 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 55,071 psi | 86% | 3363 fps | 98.9% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 54,563 psi | 86% | 3389 fps | 98.6% |
| Rottweil R 901 | <<locked>> | 84% | 55,042 psi | 86% | 3228 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 54,433 psi | 85% | 3235 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 57,406 psi | 90% | 3330 fps | 100% |
| Rottweil R 907 | <<locked>> | 96% | 57,261 psi | 90% | 3294 fps | 96.6% |
| Shooters World Long Rifle | <<locked>> | 96% | 55,303 psi | 87% | 3271 fps | 98.1% |
| Shooters World Match Rifle | <<locked>> | 86% | 55,448 psi | 87% | 3274 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 55,811 psi | 87% | 3278 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 56,376 psi | 88% | 3307 fps | 97.3% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 55,303 psi | 87% | 3333 fps | 99.7% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 56,913 psi | 89% | 3294 fps | 98.8% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 57,261 psi | 90% | 3317 fps | 99.8% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 55,535 psi | 87% | 3182 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 55,883 psi | 88% | 3173 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 55,608 psi | 87% | 3215 fps | 96.9% |
| Somchem S321 | <<locked>> | 82% | 55,419 psi | 87% | 3274 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 55,027 psi | 86% | 3176 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 56,289 psi | 88% | 3281 fps | 99.7% |
| Somchem S355 | <<locked>> | 94% | 57,348 psi | 90% | 3323 fps | 99.9% |
| Somchem S365ᴾ | <<locked>> | 100% | 52,315 psi | 82% | 3333 fps | 100% |
| Unknown powder | <<locked>> | 96% | 55,347 psi | 87% | 3340 fps | 98.6% |
| Vihtavuori N130 | <<locked>> | 82% | 55,172 psi | 86% | 3146 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 55,782 psi | 87% | 3166 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 54,360 psi | 85% | 3205 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 55,172 psi | 86% | 3219 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 55,550 psi | 87% | 3248 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 56,710 psi | 89% | 3327 fps | 99.1% |
| Vihtavuori N530 | <<locked>> | 84% | 54,781 psi | 86% | 3245 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 56,971 psi | 89% | 3264 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 56,043 psi | 88% | 3333 fps | 99% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 44,672 psi | 70% | 3186 fps | 97.9% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 57,479 psi | 90% | 3304 fps | 100% |
| Winchester 748 | <<locked>> | 82% | 55,201 psi | 87% | 3301 fps | 100% |
| Winchester 760 | <<locked>> | 94% | 56,159 psi | 88% | 3366 fps | 97.1% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 36,289 psi | 57% | 3074 fps | 97.4% |
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% | 49,414 psi | 77% | 3091 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 47,152 psi | 74% | 3117 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 48,080 psi | 75% | 3150 fps | 100% |
| Accurate 2700 | <<locked>> | 90% | 52,011 psi | 82% | 3143 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 39,871 psi | 62% | 2979 fps | 99.8% |
| Accurate 4350 | <<locked>> | 88% | 38,885 psi | 61% | 3012 fps | 95.4% |
| ADI AR 2206H | <<locked>> | 80% | 45,745 psi | 72% | 3114 fps | 98.5% |
| ADI AR 2208 | <<locked>> | 80% | 38,740 psi | 61% | 2933 fps | 96.1% |
| ADI Benchmark 8208 | <<locked>> | 80% | 47,834 psi | 75% | 3127 fps | 99.5% |
| Alliant AR-Comp | <<locked>> | 80% | 48,254 psi | 76% | 3120 fps | 100% |
| Alliant Power Pro 2000-MR | 45.3 gr | 80% | 41,597 psi | 65% | 3133 fps | 96.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 38,595 psi | 60% | 2963 fps | 97.7% |
| Alliant Reloder-15 | <<locked>> | 80% | 41,452 psi | 65% | 3035 fps | 97% |
| Alliant Reloder-16 | <<locked>> | 88% | 38,537 psi | 60% | 3025 fps | 95.5% |
| Alliant Reloder-17 | 44.6 gr | 80% | 33,286 psi | 52% | 2900 fps | 95.1% |
| Alliant Reloder-23 | <<locked>> | 94% | 33,417 psi | 52% | 2897 fps | 95.1% |
| Alliant Reloder-26 | <<locked>> | 98% | 42,583 psi | 67% | 3199 fps | 96.2% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 45,049 psi | 71% | 3107 fps | 97.4% |
| Bofors RP3 | <<locked>> | 80% | 38,218 psi | 60% | 2959 fps | 97.7% |
| Bofors RP7 | <<locked>> | 92% | 50,430 psi | 79% | 3169 fps | 95% |
| Hodgdon Benchmark | <<locked>> | 80% | 49,313 psi | 77% | 3117 fps | 99.9% |
| Hodgdon BL-C2 | <<locked>> | 80% | 46,760 psi | 73% | 3143 fps | 99.7% |
| Hodgdon CFE223 | <<locked>> | 80% | 51,822 psi | 81% | 3314 fps | 99.1% |
| Hodgdon H322 | <<locked>> | 80% | 50,633 psi | 79% | 3176 fps | 100% |
| Hodgdon H380 | <<locked>> | 82% | 41,887 psi | 66% | 3028 fps | 95.8% |
| Hodgdon H414 | <<locked>> | 90% | 48,704 psi | 76% | 3225 fps | 95.4% |
| Hodgdon H4895 | <<locked>> | 80% | 46,209 psi | 72% | 3127 fps | 98.9% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 33,315 psi | 52% | 2844 fps | 95.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 39,726 psi | 62% | 3028 fps | 98.1% |
| Hodgdon Superformance | <<locked>> | 94% | 51,648 psi | 81% | 3301 fps | 95.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,252 psi | 41% | 1857 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 41,002 psi | 64% | 2999 fps | 97.9% |
| IMR 3031 | <<locked>> | 80% | 41,945 psi | 66% | 3051 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 37,971 psi | 60% | 2910 fps | 96.1% |
| IMR 4166 Enduron | <<locked>> | 88% | 48,196 psi | 76% | 3104 fps | 95.1% |
| IMR 4350 | <<locked>> | 96% | 50,937 psi | 80% | 3199 fps | 95.2% |
| IMR 4451 Enduron | <<locked>> | 90% | 49,182 psi | 77% | 3150 fps | 95.3% |
| IMR 4831 | <<locked>> | 92% | 38,377 psi | 60% | 2982 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 42,482 psi | 67% | 3071 fps | 97.8% |
| IMR 8208 XBR | <<locked>> | 80% | 47,834 psi | 75% | 3127 fps | 99.5% |
| Lovex D073.6 | <<locked>> | 80% | 45,136 psi | 71% | 3094 fps | 99.9% |
| Lovex S060 | <<locked>> | 80% | 45,498 psi | 71% | 3045 fps | 98.5% |
| Lovex S062 | <<locked>> | 80% | 40,683 psi | 64% | 2982 fps | 98.5% |
| Lovex S065 | <<locked>> | 88% | 43,033 psi | 67% | 3025 fps | 95.2% |
| Lovex S070 | <<locked>> | 94% | 49,647 psi | 78% | 3179 fps | 95.8% |
| Norma 201 | <<locked>> | 80% | 44,614 psi | 70% | 3058 fps | 99.2% |
| Norma 202 | <<locked>> | 80% | 45,136 psi | 71% | 3074 fps | 100% |
| Norma 203B | <<locked>> | 80% | 40,843 psi | 64% | 3022 fps | 97.4% |
| Norma URP | <<locked>> | 88% | 38,928 psi | 61% | 3012 fps | 95.3% |
| Ramshot Big Game | <<locked>> | 80% | 40,350 psi | 63% | 3028 fps | 97.1% |
| Ramshot Hunter | <<locked>> | 94% | 46,383 psi | 73% | 3182 fps | 95.7% |
| Ramshot TAC | <<locked>> | 80% | 47,848 psi | 75% | 3123 fps | 96.7% |
| Ramshot Wild Boar | <<locked>> | 80% | 47,456 psi | 74% | 3150 fps | 98.8% |
| Ramshot X-Terminator | <<locked>> | 80% | 51,517 psi | 81% | 3179 fps | 99.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,643 psi | 42% | 1900 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 53,505 psi | 84% | 3225 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 45,150 psi | 71% | 3071 fps | 95% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 43,830 psi | 69% | 3153 fps | 97.5% |
| ReloadSwiss RS 60 | 44.6 gr | 80% | 35,418 psi | 56% | 2986 fps | 98.5% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 38,769 psi | 61% | 3028 fps | 95% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 41,423 psi | 65% | 3104 fps | 95.1% |
| Rottweil R 901 | <<locked>> | 80% | 48,573 psi | 76% | 3117 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,453 psi | 67% | 3002 fps | 98.8% |
| Rottweil R 903 | <<locked>> | 80% | 35,969 psi | 56% | 2897 fps | 96.7% |
| Rottweil R 907 | <<locked>> | 92% | 50,430 psi | 79% | 3169 fps | 95% |
| Shooters World Long Rifle | <<locked>> | 88% | 43,033 psi | 67% | 3025 fps | 95.2% |
| Shooters World Match Rifle | <<locked>> | 80% | 45,136 psi | 71% | 3094 fps | 99.9% |
| Shooters World Precision | <<locked>> | 80% | 40,683 psi | 64% | 2982 fps | 98.5% |
| Shooters World SW4350 | <<locked>> | 94% | 49,647 psi | 78% | 3179 fps | 95.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 37,072 psi | 58% | 2949 fps | 96.1% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 46,311 psi | 73% | 3097 fps | 96.9% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 44,338 psi | 69% | 3077 fps | 98.2% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 46,093 psi | 72% | 3018 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 38,435 psi | 60% | 2858 fps | 99.9% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 48,834 psi | 77% | 3091 fps | 95.3% |
| Somchem S321 | <<locked>> | 80% | 51,895 psi | 81% | 3215 fps | 99.9% |
| Somchem S335 | <<locked>> | 80% | 45,513 psi | 71% | 3012 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 45,890 psi | 72% | 3091 fps | 98.4% |
| Somchem S355 | <<locked>> | 80% | 36,680 psi | 57% | 2904 fps | 96.7% |
| Somchem S365 | <<locked>> | 84% | 30,632 psi | 48% | 2822 fps | 95.7% |
| Unknown powder | <<locked>> | 88% | 42,308 psi | 66% | 3081 fps | 95.7% |
| Vihtavuori N130 | <<locked>> | 80% | 51,938 psi | 81% | 3094 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 46,427 psi | 73% | 3015 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 42,163 psi | 66% | 2995 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 42,656 psi | 67% | 2995 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 34,983 psi | 55% | 2835 fps | 97.6% |
| Vihtavuori N160 | <<locked>> | 86% | 38,159 psi | 60% | 2953 fps | 95% |
| Vihtavuori N530 | <<locked>> | 80% | 47,834 psi | 75% | 3120 fps | 99.6% |
| Vihtavuori N540 | <<locked>> | 80% | 41,263 psi | 65% | 2979 fps | 99.8% |
| Vihtavuori N550 | <<locked>> | 88% | 40,074 psi | 63% | 3012 fps | 95.5% |
| Vihtavuori N555 | <<locked>> | 94% | 36,260 psi | 57% | 2989 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 33,199 psi | 52% | 2795 fps | 95.5% |
| Winchester 748 | <<locked>> | 80% | 51,619 psi | 81% | 3241 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 48,704 psi | 76% | 3225 fps | 95.4% |
| Winchester StaBALL HD | <<locked>> | 98% | 33,910 psi | 53% | 2992 fps | 96.1% |
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 110 powders for .255 GS loaded with the .257 | 90gr | Reichenberg HDB Universal. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,422 fps; across all powders the maximum-charge window runs from 2,073 fps to 3,422 fps. Accurate 3100 gives the best case fill at 100 %, and 110 of the 110 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 90.0 gr projectile in 0.257" calls for a 1:11.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, 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 Power Pro 2000-MR, ReloadSwiss RS 60, Alliant Reloder-17 rank at the top here: for .255 GS with the .257 | 90gr | Reichenberg HDB Universal they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 3100, ADI AR 2209, Alliant Reloder-19 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.