Load Specifications
Load data in caliber 8.5 x 63 R with .338 | 300gr | MAKER .338 ARC/Spectre Expanding Subsonic 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 70, Alliant Reloder-17 and ReloadSwiss RS 60.
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: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 82% | 49,617 psi | 90% | 2001 fps | 100% |
| Accurate 2495 | <<locked>> | 86% | 47,427 psi | 86% | 2021 fps | 100% |
| Accurate 2520 | <<locked>> | 82% | 49,066 psi | 89% | 2070 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 47,007 psi | 85% | 2021 fps | 96.7% |
| Accurate 3100ᴾ | <<locked>> | 100% | 37,202 psi | 68% | 1985 fps | 96.4% |
| Accurate 4064 | <<locked>> | 88% | 47,572 psi | 86% | 2060 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 49,110 psi | 89% | 2159 fps | 99.8% |
| ADI AR 2206H | <<locked>> | 84% | 48,298 psi | 88% | 2080 fps | 100% |
| ADI AR 2208 | <<locked>> | 90% | 49,255 psi | 89% | 2083 fps | 99.9% |
| ADI Benchmark 8208 | <<locked>> | 82% | 47,558 psi | 86% | 2041 fps | 100% |
| Alliant AR-Comp | <<locked>> | 82% | 47,863 psi | 87% | 2021 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 86% | 47,021 psi | 85% | 2165 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 90% | 48,892 psi | 89% | 2100 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 88% | 49,385 psi | 90% | 2113 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 98% | 48,298 psi | 88% | 2165 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 94% | 48,559 psi | 88% | 2192 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 36,274 psi | 66% | 2011 fps | 99.2% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 40,059 psi | 73% | 2133 fps | 98.5% |
| Baschieri & Pellagri 107 | <<locked>> | 84% | 47,485 psi | 86% | 2093 fps | 99.6% |
| Bofors RP3 | <<locked>> | 90% | 48,878 psi | 89% | 2110 fps | 100% |
| Bofors RP7 | <<locked>> | 94% | 49,748 psi | 90% | 2090 fps | 97.5% |
| Hodgdon Benchmark | <<locked>> | 82% | 49,516 psi | 90% | 2031 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 84% | 49,487 psi | 90% | 2106 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 46,978 psi | 85% | 2080 fps | 99.3% |
| Hodgdon H414 | <<locked>> | 96% | 49,081 psi | 89% | 2162 fps | 98.2% |
| Hodgdon H4350 | <<locked>> | 92% | 47,195 psi | 86% | 2090 fps | 96.4% |
| Hodgdon H4895 | <<locked>> | 84% | 48,718 psi | 88% | 2087 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 47,355 psi | 86% | 2110 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 86% | 47,645 psi | 86% | 2116 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 49,240 psi | 89% | 2185 fps | 97.7% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,331 psi | 64% | 1257 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 46,934 psi | 85% | 2054 fps | 100% |
| IMR 3031 | <<locked>> | 84% | 48,443 psi | 88% | 2070 fps | 100% |
| IMR 4064 | <<locked>> | 88% | 48,718 psi | 88% | 2067 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 86% | 49,095 psi | 89% | 2054 fps | 97.9% |
| IMR 4350 | <<locked>> | 98% | 49,545 psi | 90% | 2110 fps | 97.5% |
| IMR 4451 Enduron | <<locked>> | 92% | 48,559 psi | 88% | 2077 fps | 97.7% |
| IMR 4831 | <<locked>> | 98% | 46,833 psi | 85% | 2116 fps | 99.6% |
| IMR 4895 | <<locked>> | 86% | 47,529 psi | 86% | 2096 fps | 100% |
| IMR 8208 XBR | <<locked>> | 82% | 47,558 psi | 86% | 2041 fps | 100% |
| Lovex D073.6 | <<locked>> | 84% | 47,413 psi | 86% | 2060 fps | 100% |
| Lovex S060 | <<locked>> | 84% | 48,486 psi | 88% | 2028 fps | 100% |
| Lovex S062 | <<locked>> | 88% | 48,486 psi | 88% | 2067 fps | 100% |
| Lovex S065 | <<locked>> | 94% | 47,645 psi | 86% | 2070 fps | 98.8% |
| Lovex S070 | <<locked>> | 96% | 48,066 psi | 87% | 2096 fps | 98% |
| Norma 201 | <<locked>> | 84% | 47,326 psi | 86% | 2037 fps | 100% |
| Norma 202 | <<locked>> | 84% | 47,848 psi | 87% | 2044 fps | 100% |
| Norma 203B | <<locked>> | 88% | 48,602 psi | 88% | 2106 fps | 100% |
| Norma 204 | <<locked>> | 98% | 49,530 psi | 90% | 2142 fps | 96.2% |
| Norma MRPᴾ | <<locked>> | 100% | 40,350 psi | 73% | 2100 fps | 95.8% |
| Norma URP | <<locked>> | 98% | 48,791 psi | 89% | 2152 fps | 99.7% |
| Ramshot Big Game | <<locked>> | 88% | 48,617 psi | 88% | 2126 fps | 100% |
| Ramshot Hunter | <<locked>> | 98% | 47,645 psi | 86% | 2149 fps | 98.6% |
| Ramshot TAC | <<locked>> | 82% | 47,369 psi | 86% | 2057 fps | 98.8% |
| Ramshot Wild Boar | <<locked>> | 82% | 46,804 psi | 85% | 2070 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,708 psi | 65% | 1286 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 88% | 47,398 psi | 86% | 2067 fps | 98.2% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 49,182 psi | 89% | 2162 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 92% | 48,675 psi | 88% | 2192 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 48,762 psi | 88% | 2182 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 98% | 48,921 psi | 89% | 2201 fps | 99.5% |
| Rottweil R 901 | <<locked>> | 82% | 48,747 psi | 88% | 2024 fps | 100% |
| Rottweil R 902 | <<locked>> | 86% | 47,892 psi | 87% | 2041 fps | 100% |
| Rottweil R 903 | <<locked>> | 92% | 48,776 psi | 89% | 2103 fps | 100% |
| Rottweil R 907 | <<locked>> | 94% | 49,748 psi | 90% | 2090 fps | 97.5% |
| Shooters World Long Rifle | <<locked>> | 94% | 47,645 psi | 86% | 2070 fps | 98.8% |
| Shooters World Match Rifle | <<locked>> | 84% | 47,413 psi | 86% | 2060 fps | 100% |
| Shooters World Precision | <<locked>> | 88% | 48,486 psi | 88% | 2067 fps | 100% |
| Shooters World SW4350 | <<locked>> | 96% | 48,066 psi | 87% | 2096 fps | 98% |
| SNPE Vectan SP 11 | <<locked>> | 90% | 47,181 psi | 86% | 2113 fps | 99.9% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 48,878 psi | 89% | 2080 fps | 99.4% |
| SNPE Vectan SP 9 | <<locked>> | 86% | 49,705 psi | 90% | 2100 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 84% | 49,182 psi | 89% | 1995 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 90% | 48,892 psi | 89% | 1995 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 47,413 psi | 86% | 2031 fps | 97.6% |
| Somchem S335 | <<locked>> | 84% | 48,341 psi | 88% | 1995 fps | 100% |
| Somchem S341 | <<locked>> | 84% | 48,443 psi | 88% | 2073 fps | 100% |
| Somchem S355 | <<locked>> | 92% | 49,414 psi | 90% | 2103 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 46,615 psi | 85% | 2156 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 43,439 psi | 79% | 2067 fps | 96.3% |
| Vihtavuori N133 | <<locked>> | 84% | 49,429 psi | 90% | 1982 fps | 100% |
| Vihtavuori N135 | <<locked>> | 86% | 47,340 psi | 86% | 2011 fps | 100% |
| Vihtavuori N140 | <<locked>> | 86% | 48,153 psi | 87% | 2028 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 47,427 psi | 86% | 2051 fps | 100% |
| Vihtavuori N160 | <<locked>> | 96% | 47,964 psi | 87% | 2110 fps | 99.5% |
| Vihtavuori N530 | <<locked>> | 82% | 47,819 psi | 87% | 2041 fps | 100% |
| Vihtavuori N540 | <<locked>> | 88% | 49,327 psi | 90% | 2064 fps | 100% |
| Vihtavuori N550 | <<locked>> | 96% | 47,195 psi | 86% | 2119 fps | 99.4% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 39,320 psi | 71% | 2070 fps | 99.1% |
| Winchester 6.5 StaBALL | <<locked>> | 96% | 48,341 psi | 88% | 2096 fps | 100% |
| Winchester 748 | <<locked>> | 82% | 47,384 psi | 86% | 2080 fps | 100% |
| Winchester 760 | <<locked>> | 96% | 49,081 psi | 89% | 2162 fps | 98.2% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 32,503 psi | 59% | 2021 fps | 99.2% |
| Winchester StaBALL Match | <<locked>> | 86% | 49,443 psi | 90% | 2106 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 80% | 46,572 psi | 85% | 1965 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 39,204 psi | 71% | 1919 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 45,701 psi | 83% | 2031 fps | 100% |
| Accurate 2700 | <<locked>> | 82% | 41,307 psi | 75% | 1939 fps | 95.3% |
| Accurate 3100 | <<locked>> | 98% | 34,809 psi | 63% | 1946 fps | 95.7% |
| Accurate 4064 | <<locked>> | 80% | 37,072 psi | 67% | 1919 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 28,543 psi | 52% | 1831 fps | 95.4% |
| ADI AR 2206H | <<locked>> | 80% | 42,656 psi | 77% | 2001 fps | 99.7% |
| ADI AR 2208 | <<locked>> | 80% | 36,506 psi | 66% | 1896 fps | 98.3% |
| ADI Benchmark 8208 | <<locked>> | 80% | 44,672 psi | 81% | 2005 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 44,730 psi | 81% | 1985 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 38,479 psi | 70% | 2031 fps | 98.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 35,897 psi | 65% | 1913 fps | 99.3% |
| Alliant Reloder-15 | <<locked>> | 80% | 38,464 psi | 70% | 1959 fps | 98.9% |
| Alliant Reloder-16 | <<locked>> | 82% | 29,849 psi | 54% | 1844 fps | 95.6% |
| Alliant Reloder-17 | 41.9 gr | 80% | 30,864 psi | 56% | 1896 fps | 97.9% |
| Alliant Reloder-23 | <<locked>> | 88% | 25,599 psi | 46% | 1778 fps | 95.2% |
| Alliant Reloder-26 | <<locked>> | 92% | 30,676 psi | 56% | 1946 fps | 95% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 41,742 psi | 76% | 2011 fps | 99% |
| Bofors RP3 | <<locked>> | 80% | 35,375 psi | 64% | 1916 fps | 99.4% |
| Bofors RP7 | <<locked>> | 88% | 41,263 psi | 75% | 1972 fps | 95.6% |
| Hodgdon Benchmark | <<locked>> | 80% | 46,586 psi | 85% | 1991 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 43,134 psi | 78% | 2024 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 36,230 psi | 66% | 1916 fps | 97.3% |
| Hodgdon H414 | <<locked>> | 88% | 37,956 psi | 69% | 1995 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 88% | 41,698 psi | 76% | 2008 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 43,004 psi | 78% | 2011 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 25,512 psi | 46% | 1729 fps | 95.6% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 38,885 psi | 71% | 1995 fps | 99.8% |
| Hodgdon Superformance | <<locked>> | 90% | 40,089 psi | 73% | 2047 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,469 psi | 48% | 1122 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 41,394 psi | 75% | 1975 fps | 99.7% |
| IMR 3031 | <<locked>> | 80% | 42,670 psi | 77% | 2001 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 38,305 psi | 70% | 1919 fps | 98.8% |
| IMR 4166 Enduron | <<locked>> | 80% | 40,611 psi | 74% | 1932 fps | 96% |
| IMR 4350 | <<locked>> | 92% | 41,220 psi | 75% | 1995 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 84% | 38,029 psi | 69% | 1919 fps | 95.2% |
| IMR 4831 | <<locked>> | 82% | 28,166 psi | 51% | 1804 fps | 95.2% |
| IMR 4895 | <<locked>> | 80% | 39,363 psi | 71% | 1978 fps | 99.4% |
| IMR 8208 XBR | <<locked>> | 80% | 44,672 psi | 81% | 2005 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 41,727 psi | 76% | 1988 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 43,149 psi | 78% | 1955 fps | 99.7% |
| Lovex S062 | <<locked>> | 80% | 38,203 psi | 69% | 1923 fps | 99.8% |
| Lovex S065 | <<locked>> | 82% | 33,344 psi | 61% | 1844 fps | 95.4% |
| Lovex S070 | <<locked>> | 88% | 37,782 psi | 69% | 1942 fps | 95.6% |
| Norma 201 | <<locked>> | 80% | 42,018 psi | 76% | 1969 fps | 100% |
| Norma 202 | <<locked>> | 80% | 42,148 psi | 76% | 1972 fps | 100% |
| Norma 203B | <<locked>> | 80% | 37,826 psi | 69% | 1949 fps | 99.1% |
| Norma 204 | <<locked>> | 96% | 46,485 psi | 84% | 2103 fps | 95.5% |
| Norma MRP | <<locked>> | 98% | 37,956 psi | 69% | 2057 fps | 95% |
| Norma URP | <<locked>> | 82% | 29,472 psi | 53% | 1834 fps | 95.4% |
| Ramshot Big Game | <<locked>> | 80% | 37,130 psi | 67% | 1959 fps | 98.9% |
| Ramshot Hunter | <<locked>> | 88% | 34,896 psi | 63% | 1946 fps | 95.4% |
| Ramshot TAC | <<locked>> | 80% | 44,628 psi | 81% | 2018 fps | 98.4% |
| Ramshot Wild Boar | <<locked>> | 80% | 44,005 psi | 80% | 2031 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,658 psi | 48% | 1148 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 36,637 psi | 66% | 1903 fps | 95.6% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 40,045 psi | 73% | 2034 fps | 99.2% |
| ReloadSwiss RS 60 | 41.9 gr | 80% | 32,837 psi | 60% | 1942 fps | 99.9% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 30,472 psi | 55% | 1883 fps | 95.6% |
| ReloadSwiss RS 70 | 45.7 gr | 86% | 32,996 psi | 60% | 1932 fps | 95.5% |
| Rottweil R 901 | <<locked>> | 80% | 45,803 psi | 83% | 1988 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 39,943 psi | 72% | 1929 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 80% | 33,257 psi | 60% | 1873 fps | 98.8% |
| Rottweil R 907 | <<locked>> | 88% | 41,263 psi | 75% | 1972 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 82% | 33,344 psi | 61% | 1844 fps | 95.4% |
| Shooters World Match Rifle | <<locked>> | 80% | 41,727 psi | 76% | 1988 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 38,203 psi | 69% | 1923 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 88% | 37,782 psi | 69% | 1942 fps | 95.6% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 34,069 psi | 62% | 1913 fps | 98.3% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 42,873 psi | 78% | 1998 fps | 98.6% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 41,060 psi | 75% | 1982 fps | 99.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 43,511 psi | 79% | 1926 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 36,085 psi | 65% | 1831 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 36,550 psi | 66% | 1877 fps | 95% |
| Somchem S335 | <<locked>> | 80% | 43,033 psi | 78% | 1929 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 42,525 psi | 77% | 1995 fps | 99.6% |
| Somchem S355 | <<locked>> | 80% | 34,316 psi | 62% | 1880 fps | 98.8% |
| Somchem S365 | <<locked>> | 80% | 24,772 psi | 45% | 1759 fps | 96.9% |
| Somchem S385 | <<locked>> | 98% | 40,770 psi | 74% | 2028 fps | 95.6% |
| Vihtavuori N133 | <<locked>> | 80% | 43,801 psi | 79% | 1916 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 39,363 psi | 71% | 1913 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 39,842 psi | 72% | 1923 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 32,489 psi | 59% | 1831 fps | 99.3% |
| Vihtavuori N160 | <<locked>> | 80% | 28,819 psi | 52% | 1795 fps | 95% |
| Vihtavuori N530 | <<locked>> | 80% | 44,860 psi | 81% | 2005 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 38,276 psi | 69% | 1919 fps | 100% |
| Vihtavuori N550 | <<locked>> | 82% | 30,066 psi | 55% | 1837 fps | 95.4% |
| Vihtavuori N555 | <<locked>> | 88% | 27,021 psi | 49% | 1834 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 28,863 psi | 52% | 1781 fps | 97.2% |
| Winchester 748 | <<locked>> | 80% | 44,179 psi | 80% | 2041 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 37,956 psi | 69% | 1995 fps | 95.5% |
| Winchester StaBALL HD | <<locked>> | 92% | 25,295 psi | 46% | 1827 fps | 95.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 40,495 psi | 73% | 1985 fps | 99.7% |
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 94 powders for 8.5 x 63 R loaded with the .338 | 300gr | MAKER .338 ARC/Spectre Expanding Subsonic. ReloadSwiss RS 70 delivers the highest muzzle velocity at 2,201 fps; across all powders the maximum-charge window runs from 1,257 fps to 2,201 fps. Accurate 3100 gives the best case fill at 100 %, and 94 of the 94 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (380 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.338" calls for a 1:11.5 twist; slower twists will usually not stabilise this weight. Accurate 3100, Alliant Reloder-23, Alliant Reloder-26 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-17, ReloadSwiss RS 60 rank at the top here: for 8.5 x 63 R with the .338 | 300gr | MAKER .338 ARC/Spectre Expanding Subsonic they combine a high case fill with complete burn and sit in the upper velocity band. Hodgdon TrailBoss stay subsonic at start load. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.