Load Specifications
Load data in caliber 6 mm XC with .243 | 90gr | Barnes X S bullet and 94 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 Reloder-17 and ReloadSwiss RS 70.
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 2015 | <<locked>> | 82% | 55,738 psi | 87% | 2995 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 55,753 psi | 87% | 3035 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 55,970 psi | 88% | 3091 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 56,347 psi | 88% | 3058 fps | 96.5% |
| Accurate 3100ᴾ | <<locked>> | 100% | 45,440 psi | 71% | 2963 fps | 96% |
| Accurate 4064 | <<locked>> | 88% | 55,738 psi | 87% | 3087 fps | 100% |
| Accurate 4350 | <<locked>> | 96% | 54,462 psi | 85% | 3156 fps | 99.2% |
| ADI AR 2206H | <<locked>> | 86% | 57,653 psi | 90% | 3150 fps | 99.9% |
| ADI AR 2208 | <<locked>> | 90% | 55,056 psi | 86% | 3091 fps | 99.5% |
| ADI Benchmark 8208 | <<locked>> | 84% | 56,579 psi | 89% | 3097 fps | 100% |
| Alliant AR-Comp | <<locked>> | 82% | 54,462 psi | 85% | 3028 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 57,014 psi | 89% | 3271 fps | 99.7% |
| Alliant Power Pro Varmint | <<locked>> | 84% | 55,245 psi | 87% | 3110 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 55,579 psi | 87% | 3123 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 56,130 psi | 88% | 3146 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 98% | 54,969 psi | 86% | 3209 fps | 99.5% |
| Alliant Reloder-17 | <<locked>> | 94% | 55,985 psi | 88% | 3248 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 42,786 psi | 67% | 2986 fps | 98.8% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 48,095 psi | 75% | 3166 fps | 98.1% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 57,290 psi | 90% | 3159 fps | 99.5% |
| Bofors RP3 | <<locked>> | 90% | 56,826 psi | 89% | 3146 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 56,202 psi | 88% | 3100 fps | 96.7% |
| Hodgdon Benchmark | <<locked>> | 82% | 54,839 psi | 86% | 3025 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 56,318 psi | 88% | 3130 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 57,319 psi | 90% | 3153 fps | 99.2% |
| Hodgdon H414 | <<locked>> | 96% | 56,608 psi | 89% | 3199 fps | 97.5% |
| Hodgdon H4350 | <<locked>> | 94% | 56,913 psi | 89% | 3156 fps | 96.2% |
| Hodgdon H4895 | <<locked>> | 84% | 55,129 psi | 86% | 3110 fps | 99.9% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 54,665 psi | 86% | 3130 fps | 99.9% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 54,317 psi | 85% | 3143 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 57,188 psi | 90% | 3235 fps | 97.2% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,187 psi | 57% | 1929 fps | 100% |
| Hodgdon VARGET | <<locked>> | 86% | 55,695 psi | 87% | 3104 fps | 99.9% |
| IMR 3031 | <<locked>> | 84% | 54,781 psi | 86% | 3091 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 54,882 psi | 86% | 3077 fps | 99.6% |
| IMR 4166 Enduron | <<locked>> | 86% | 54,520 psi | 85% | 3048 fps | 97% |
| IMR 4350 | <<locked>> | 98% | 55,999 psi | 88% | 3120 fps | 96.8% |
| IMR 4451 Enduron | <<locked>> | 94% | 57,725 psi | 90% | 3133 fps | 97.5% |
| IMR 4831 | <<locked>> | 98% | 54,723 psi | 86% | 3143 fps | 99.3% |
| IMR 4895 | <<locked>> | 88% | 57,522 psi | 90% | 3179 fps | 99.9% |
| IMR 8208 XBR | <<locked>> | 84% | 56,579 psi | 89% | 3097 fps | 100% |
| Lovex D073.6 | <<locked>> | 84% | 54,810 psi | 86% | 3081 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 56,695 psi | 89% | 3068 fps | 99.9% |
| Lovex S062 | <<locked>> | 88% | 55,259 psi | 87% | 3084 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 57,551 psi | 90% | 3130 fps | 98.6% |
| Lovex S070 | <<locked>> | 96% | 55,405 psi | 87% | 3114 fps | 97.4% |
| Norma 201 | <<locked>> | 86% | 56,884 psi | 89% | 3097 fps | 100% |
| Norma 202 | <<locked>> | 86% | 57,043 psi | 89% | 3094 fps | 100% |
| Norma 203B | <<locked>> | 88% | 55,419 psi | 87% | 3130 fps | 99.8% |
| Norma URP | <<locked>> | 98% | 56,376 psi | 88% | 3192 fps | 99.4% |
| Ramshot Big Game | <<locked>> | 88% | 55,390 psi | 87% | 3150 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 98% | 54,940 psi | 86% | 3179 fps | 98% |
| Ramshot TAC | <<locked>> | 84% | 56,782 psi | 89% | 3114 fps | 98.7% |
| Ramshot Wild Boar | <<locked>> | 84% | 56,347 psi | 88% | 3133 fps | 99.8% |
| Ramshot X-Terminator | <<locked>> | 82% | 57,363 psi | 90% | 3097 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,550 psi | 57% | 1969 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 57,174 psi | 90% | 3127 fps | 98% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 56,362 psi | 88% | 3212 fps | 99.7% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 55,709 psi | 87% | 3248 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 57,450 psi | 90% | 3235 fps | 99.4% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 56,405 psi | 88% | 3255 fps | 99.1% |
| Rottweil R 901 | <<locked>> | 82% | 54,926 psi | 86% | 3031 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 57,392 psi | 90% | 3094 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 56,666 psi | 89% | 3136 fps | 100% |
| Rottweil R 907 | <<locked>> | 94% | 56,202 psi | 88% | 3100 fps | 96.7% |
| Shooters World Long Rifle | <<locked>> | 96% | 57,551 psi | 90% | 3130 fps | 98.6% |
| Shooters World Match Rifle | <<locked>> | 84% | 54,810 psi | 86% | 3081 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 55,259 psi | 87% | 3084 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 55,405 psi | 87% | 3114 fps | 97.4% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 57,609 psi | 90% | 3192 fps | 99.9% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 55,709 psi | 87% | 3094 fps | 98.9% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 55,869 psi | 88% | 3114 fps | 99.8% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 54,520 psi | 85% | 2979 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 54,491 psi | 85% | 2972 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 54,215 psi | 85% | 3018 fps | 96.9% |
| Somchem S335 | <<locked>> | 86% | 57,392 psi | 90% | 3025 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 54,868 psi | 86% | 3081 fps | 99.7% |
| Somchem S355 | <<locked>> | 92% | 56,362 psi | 88% | 3127 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 54,607 psi | 86% | 3199 fps | 100% |
| Vihtavuori N130 | <<locked>> | 82% | 57,493 psi | 90% | 2986 fps | 100% |
| Vihtavuori N133 | <<locked>> | 84% | 54,650 psi | 86% | 2963 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 56,971 psi | 89% | 3054 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 57,595 psi | 90% | 3071 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 54,476 psi | 85% | 3054 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 55,347 psi | 87% | 3133 fps | 99.2% |
| Vihtavuori N530 | <<locked>> | 84% | 57,276 psi | 90% | 3100 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 55,825 psi | 87% | 3068 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 54,621 psi | 86% | 3140 fps | 99% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 47,369 psi | 74% | 3077 fps | 98.7% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 55,550 psi | 87% | 3107 fps | 100% |
| Winchester 748 | <<locked>> | 84% | 56,927 psi | 89% | 3146 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 56,608 psi | 89% | 3199 fps | 97.5% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 38,711 psi | 61% | 2995 fps | 98.8% |
| Winchester StaBALL Match | <<locked>> | 86% | 55,883 psi | 88% | 3127 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% | 52,663 psi | 83% | 2949 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 46,557 psi | 73% | 2887 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 52,489 psi | 82% | 3035 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 49,705 psi | 78% | 2940 fps | 95% |
| Accurate 3100 | <<locked>> | 98% | 42,757 psi | 67% | 2907 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 43,976 psi | 69% | 2881 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 37,188 psi | 58% | 2805 fps | 95.5% |
| ADI AR 2206H | <<locked>> | 80% | 48,124 psi | 75% | 2979 fps | 99.1% |
| ADI AR 2208 | <<locked>> | 80% | 41,017 psi | 64% | 2815 fps | 97.3% |
| ADI Benchmark 8208 | <<locked>> | 80% | 49,966 psi | 78% | 2982 fps | 99.8% |
| Alliant AR-Comp | <<locked>> | 80% | 50,850 psi | 80% | 2972 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 44,048 psi | 69% | 3015 fps | 97.9% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 48,689 psi | 76% | 2992 fps | 99.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 41,336 psi | 65% | 2851 fps | 98.7% |
| Alliant Reloder-15 | <<locked>> | 80% | 43,918 psi | 69% | 2913 fps | 98.1% |
| Alliant Reloder-16 | <<locked>> | 84% | 36,289 psi | 57% | 2795 fps | 95.1% |
| Alliant Reloder-17 | 36 gr | 80% | 35,795 psi | 56% | 2812 fps | 96.9% |
| Alliant Reloder-23 | <<locked>> | 90% | 32,126 psi | 50% | 2703 fps | 95.1% |
| Alliant Reloder-26 | <<locked>> | 94% | 39,305 psi | 62% | 2959 fps | 95.4% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 47,485 psi | 74% | 2986 fps | 98.3% |
| Bofors RP3 | <<locked>> | 80% | 41,481 psi | 65% | 2861 fps | 98.8% |
| Bofors RP7 | <<locked>> | 90% | 49,850 psi | 78% | 2986 fps | 95.3% |
| Hodgdon Benchmark | <<locked>> | 80% | 51,532 psi | 81% | 2969 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 49,603 psi | 78% | 3018 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 41,974 psi | 66% | 2858 fps | 96.4% |
| Hodgdon H414 | <<locked>> | 90% | 46,615 psi | 73% | 3015 fps | 95.3% |
| Hodgdon H4350 | <<locked>> | 92% | 53,432 psi | 84% | 3094 fps | 95.4% |
| Hodgdon H4895 | <<locked>> | 80% | 48,588 psi | 76% | 2992 fps | 99.5% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 31,966 psi | 50% | 2641 fps | 95.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 44,817 psi | 70% | 2966 fps | 99.3% |
| Hodgdon Superformance | <<locked>> | 92% | 49,879 psi | 78% | 3100 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,122 psi | 43% | 1726 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 46,369 psi | 73% | 2936 fps | 99.2% |
| IMR 3031 | <<locked>> | 80% | 48,660 psi | 76% | 2992 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 43,091 psi | 68% | 2854 fps | 98% |
| IMR 4166 Enduron | <<locked>> | 82% | 48,153 psi | 75% | 2927 fps | 95.6% |
| IMR 4350 | <<locked>> | 94% | 49,705 psi | 78% | 3009 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 88% | 48,225 psi | 76% | 2959 fps | 95.5% |
| IMR 4831 | <<locked>> | 86% | 37,956 psi | 59% | 2805 fps | 95.8% |
| IMR 4895 | <<locked>> | 80% | 44,962 psi | 70% | 2946 fps | 98.7% |
| IMR 8208 XBR | <<locked>> | 80% | 49,966 psi | 78% | 2982 fps | 99.8% |
| Lovex D073.6 | <<locked>> | 80% | 48,167 psi | 75% | 2969 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 47,674 psi | 75% | 2907 fps | 99.1% |
| Lovex S062 | <<locked>> | 80% | 43,555 psi | 68% | 2864 fps | 99.3% |
| Lovex S065 | <<locked>> | 84% | 40,814 psi | 64% | 2805 fps | 95% |
| Lovex S070 | <<locked>> | 90% | 46,296 psi | 73% | 2943 fps | 95.4% |
| Norma 201 | <<locked>> | 80% | 47,761 psi | 75% | 2936 fps | 99.7% |
| Norma 202 | <<locked>> | 80% | 47,834 psi | 75% | 2940 fps | 100% |
| Norma 203B | <<locked>> | 80% | 43,323 psi | 68% | 2900 fps | 98.4% |
| Norma URP | <<locked>> | 84% | 36,796 psi | 58% | 2792 fps | 95.2% |
| Ramshot Big Game | <<locked>> | 80% | 42,931 psi | 67% | 2917 fps | 98.2% |
| Ramshot Hunter | <<locked>> | 90% | 43,033 psi | 67% | 2946 fps | 95.2% |
| Ramshot TAC | <<locked>> | 80% | 49,951 psi | 78% | 2989 fps | 97.6% |
| Ramshot Wild Boar | <<locked>> | 80% | 49,748 psi | 78% | 3018 fps | 99.3% |
| Ramshot X-Terminator | <<locked>> | 80% | 53,969 psi | 85% | 3041 fps | 99.6% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,514 psi | 43% | 1765 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 44,643 psi | 70% | 2890 fps | 95.4% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 46,514 psi | 73% | 3031 fps | 98.5% |
| ReloadSwiss RS 60 | 36 gr | 80% | 37,884 psi | 59% | 2884 fps | 99.5% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 38,841 psi | 61% | 2871 fps | 95.6% |
| ReloadSwiss RS 70 | 40.2 gr | 88% | 40,799 psi | 64% | 2927 fps | 95.4% |
| Rottweil R 901 | <<locked>> | 80% | 52,011 psi | 82% | 2982 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 45,556 psi | 71% | 2884 fps | 99.5% |
| Rottweil R 903 | <<locked>> | 80% | 39,262 psi | 62% | 2802 fps | 98.1% |
| Rottweil R 907 | <<locked>> | 90% | 49,850 psi | 78% | 2986 fps | 95.3% |
| Shooters World Long Rifle | <<locked>> | 84% | 40,814 psi | 64% | 2805 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 48,167 psi | 75% | 2969 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 43,555 psi | 68% | 2864 fps | 99.3% |
| Shooters World SW4350 | <<locked>> | 90% | 46,296 psi | 73% | 2943 fps | 95.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 39,595 psi | 62% | 2848 fps | 97.5% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 48,762 psi | 76% | 2969 fps | 97.8% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 46,731 psi | 73% | 2949 fps | 99% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 48,544 psi | 76% | 2877 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 40,785 psi | 64% | 2733 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 48,095 psi | 75% | 2907 fps | 95.6% |
| Somchem S335 | <<locked>> | 80% | 48,356 psi | 76% | 2881 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 48,385 psi | 76% | 2969 fps | 99.1% |
| Somchem S355 | <<locked>> | 80% | 39,682 psi | 62% | 2805 fps | 98% |
| Somchem S365 | <<locked>> | 80% | 29,617 psi | 46% | 2631 fps | 95.9% |
| Vihtavuori N130 | <<locked>> | 80% | 54,331 psi | 85% | 2940 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 48,747 psi | 76% | 2867 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 45,092 psi | 71% | 2864 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 45,339 psi | 71% | 2871 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 37,811 psi | 59% | 2733 fps | 98.7% |
| Vihtavuori N160 | <<locked>> | 84% | 38,261 psi | 60% | 2792 fps | 95.6% |
| Vihtavuori N530 | <<locked>> | 80% | 50,328 psi | 79% | 2986 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 80% | 43,816 psi | 69% | 2858 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 37,666 psi | 59% | 2789 fps | 95.2% |
| Vihtavuori N555 | <<locked>> | 90% | 34,838 psi | 55% | 2792 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 33,504 psi | 53% | 2648 fps | 96.3% |
| Winchester 748 | <<locked>> | 80% | 50,430 psi | 79% | 3038 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 46,963 psi | 74% | 3022 fps | 95.4% |
| Winchester StaBALL HD | <<locked>> | 94% | 32,489 psi | 51% | 2795 fps | 95.8% |
| Winchester StaBALL Match | <<locked>> | 80% | 46,267 psi | 73% | 2953 fps | 99.3% |
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 111 powders for 6 mm XC loaded with the .243 | 90gr | Barnes X S. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 3,271 fps; across all powders the maximum-charge window runs from 1,929 fps to 3,271 fps. Accurate 3100 gives the best case fill at 100 %, and 111 of the 111 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 90.0 gr projectile in 0.243" calls for a 1:9.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate High Country, ADI AR 2209 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 Reloder-17, ReloadSwiss RS 70 rank at the top here: for 6 mm XC with the .243 | 90gr | Barnes X S they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate High Country, 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.