Load Specifications
Load data in caliber 9.3 x 66 Sako with .366 | 286gr | North Fork Semi Spitz 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 Power Pro 2000-MR, ReloadSwiss RS 52 and Hodgdon CFE223.
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>> | 90% | 52,808 psi | 88% | 2267 fps | 100% |
| Accurate 2200 | <<locked>> | 82% | 53,055 psi | 88% | 2343 fps | 99% |
| Accurate 2230 | <<locked>> | 82% | 53,795 psi | 89% | 2356 fps | 99.3% |
| Accurate 2460 | <<locked>> | 86% | 51,140 psi | 85% | 2290 fps | 100% |
| Accurate 2495 | <<locked>> | 96% | 52,431 psi | 87% | 2316 fps | 100% |
| Accurate 2520 | <<locked>> | 92% | 53,780 psi | 89% | 2369 fps | 100% |
| Accurate 2520 | <<locked>> | 92% | 53,780 psi | 89% | 2369 fps | 100% |
| Accurate 4064 | <<locked>> | 98% | 51,967 psi | 86% | 2349 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 40,886 psi | 68% | 2260 fps | 96.5% |
| Accurate LT-30 | <<locked>> | 84% | 53,330 psi | 89% | 2221 fps | 100% |
| Accurate LT-32 | <<locked>> | 84% | 53,795 psi | 89% | 2241 fps | 100% |
| ADI AR 2206H | <<locked>> | 92% | 51,474 psi | 86% | 2339 fps | 99.3% |
| ADI AR 2208 | <<locked>> | 98% | 52,359 psi | 87% | 2333 fps | 98.9% |
| ADI AR 2219 | <<locked>> | 84% | 53,127 psi | 88% | 2323 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 92% | 54,273 psi | 90% | 2346 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 92% | 53,461 psi | 89% | 2326 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 86% | 52,359 psi | 87% | 2388 fps | 99.7% |
| Alliant Power Pro 2000-MR | <<locked>> | 96% | 54,215 psi | 90% | 2477 fps | 99.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 98% | 51,111 psi | 85% | 2352 fps | 99.7% |
| Alliant Reloder-10x | <<locked>> | 86% | 52,794 psi | 88% | 2274 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 96% | 52,156 psi | 87% | 2369 fps | 99.1% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 42,206 psi | 70% | 2267 fps | 96.7% |
| Alliant Reloder-17ᴾ | <<locked>> | 100% | 48,269 psi | 80% | 2398 fps | 99.4% |
| Baschieri & Pellagri 106 | <<locked>> | 84% | 52,040 psi | 86% | 2224 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 92% | 50,836 psi | 84% | 2349 fps | 98.5% |
| Bofors RP3 | <<locked>> | 98% | 51,329 psi | 85% | 2365 fps | 99.8% |
| Hodgdon Benchmark | <<locked>> | 90% | 53,548 psi | 89% | 2293 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 92% | 52,823 psi | 88% | 2375 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 90% | 54,418 psi | 90% | 2451 fps | 99.4% |
| Hodgdon H322 | <<locked>> | 90% | 54,317 psi | 90% | 2336 fps | 100% |
| Hodgdon H335 | <<locked>> | 84% | 52,243 psi | 87% | 2326 fps | 100% |
| Hodgdon H380 | <<locked>> | 98% | 53,171 psi | 88% | 2372 fps | 98.3% |
| Hodgdon H4198 | <<locked>> | 82% | 52,040 psi | 86% | 2221 fps | 100% |
| Hodgdon H4895 | <<locked>> | 92% | 51,880 psi | 86% | 2349 fps | 99.6% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 38,334 psi | 64% | 2172 fps | 97.3% |
| Hodgdon LEVERevolution | <<locked>> | 98% | 53,316 psi | 89% | 2415 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,345 psi | 57% | 1375 fps | 100% |
| Hodgdon VARGET | <<locked>> | 96% | 52,054 psi | 86% | 2336 fps | 99.6% |
| IMR 3031 | <<locked>> | 96% | 52,112 psi | 87% | 2356 fps | 100% |
| IMR 4064ᴾ | <<locked>> | 100% | 53,969 psi | 90% | 2346 fps | 99.3% |
| IMR 4198 | <<locked>> | 86% | 53,737 psi | 89% | 2241 fps | 100% |
| IMR 4895 | <<locked>> | 96% | 53,417 psi | 89% | 2395 fps | 99.6% |
| IMR 8208 XBR | <<locked>> | 92% | 54,273 psi | 90% | 2346 fps | 99.9% |
| Lovex D073.4 | <<locked>> | 86% | 53,461 psi | 89% | 2316 fps | 100% |
| Lovex D073.5 | <<locked>> | 88% | 54,447 psi | 90% | 2339 fps | 100% |
| Lovex D073.6 | <<locked>> | 94% | 53,447 psi | 89% | 2365 fps | 100% |
| Lovex S060 | <<locked>> | 92% | 52,315 psi | 87% | 2283 fps | 99.3% |
| Lovex S062 | <<locked>> | 98% | 54,230 psi | 90% | 2359 fps | 100% |
| Lovex S065ᴾ | <<locked>> | 100% | 47,195 psi | 78% | 2267 fps | 96.3% |
| Norma 200 | <<locked>> | 82% | 52,794 psi | 88% | 2251 fps | 100% |
| Norma 201 | <<locked>> | 94% | 53,548 psi | 89% | 2336 fps | 99.9% |
| Norma 202 | <<locked>> | 94% | 53,809 psi | 89% | 2343 fps | 100% |
| Norma 203B | <<locked>> | 96% | 51,198 psi | 85% | 2359 fps | 99.3% |
| Norma URPᴾ | <<locked>> | 100% | 41,872 psi | 70% | 2260 fps | 96.5% |
| Ramshot Big Game | <<locked>> | 96% | 51,488 psi | 86% | 2382 fps | 99.2% |
| Ramshot TAC | <<locked>> | 90% | 51,590 psi | 86% | 2316 fps | 97.4% |
| Ramshot Wild Boar | <<locked>> | 92% | 53,693 psi | 89% | 2375 fps | 99.5% |
| Ramshot X-Terminator | <<locked>> | 88% | 52,417 psi | 87% | 2306 fps | 99.2% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 34,664 psi | 58% | 1407 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 88% | 54,186 psi | 90% | 2336 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 98% | 53,983 psi | 90% | 2356 fps | 96.9% |
| ReloadSwiss RS 52 | <<locked>> | 94% | 51,517 psi | 86% | 2421 fps | 99.1% |
| ReloadSwiss RS 60ᴾ | <<locked>> | 100% | 51,605 psi | 86% | 2451 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 41,147 psi | 68% | 2274 fps | 96% |
| Rottweil R 901 | <<locked>> | 90% | 51,619 psi | 86% | 2287 fps | 100% |
| Rottweil R 902 | <<locked>> | 96% | 53,998 psi | 90% | 2333 fps | 99.9% |
| Rottweil R 903ᴾ | <<locked>> | 100% | 50,894 psi | 85% | 2352 fps | 99.6% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 47,195 psi | 78% | 2267 fps | 96.3% |
| Shooters World Match Rifle | <<locked>> | 94% | 53,447 psi | 89% | 2365 fps | 100% |
| Shooters World Precision | <<locked>> | 98% | 54,230 psi | 90% | 2359 fps | 100% |
| Shooters World Tactical Rifle | <<locked>> | 86% | 54,418 psi | 90% | 2313 fps | 99.8% |
| SNPE Vectan SP 10 | <<locked>> | 84% | 53,693 psi | 89% | 2336 fps | 100% |
| SNPE Vectan SP 11ᴾ | <<locked>> | 100% | 53,011 psi | 88% | 2408 fps | 99.4% |
| SNPE Vectan SP 3 | <<locked>> | 86% | 54,012 psi | 90% | 2290 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 92% | 52,852 psi | 88% | 2339 fps | 98.1% |
| SNPE Vectan SP 9 | <<locked>> | 94% | 53,069 psi | 88% | 2359 fps | 99.4% |
| SNPE Vectan Tubal 3000 | <<locked>> | 92% | 52,968 psi | 88% | 2254 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 98% | 51,982 psi | 86% | 2251 fps | 100% |
| Somchem S321 | <<locked>> | 88% | 52,083 psi | 87% | 2339 fps | 99.9% |
| Somchem S335 | <<locked>> | 92% | 51,735 psi | 86% | 2254 fps | 100% |
| Somchem S341 | <<locked>> | 92% | 52,040 psi | 86% | 2333 fps | 99.3% |
| Somchem S355ᴾ | <<locked>> | 100% | 51,851 psi | 86% | 2352 fps | 99.6% |
| Somchem S365ᴾ | <<locked>> | 100% | 37,188 psi | 62% | 2215 fps | 98.5% |
| Unknown powderᴾ | <<locked>> | 100% | 46,093 psi | 77% | 2313 fps | 96.8% |
| Vihtavuori N130 | <<locked>> | 88% | 52,852 psi | 88% | 2231 fps | 100% |
| Vihtavuori N133 | <<locked>> | 92% | 52,765 psi | 88% | 2244 fps | 100% |
| Vihtavuori N135 | <<locked>> | 96% | 52,518 psi | 87% | 2306 fps | 100% |
| Vihtavuori N140 | <<locked>> | 96% | 54,157 psi | 90% | 2323 fps | 100% |
| Vihtavuori N150ᴾ | <<locked>> | 100% | 50,024 psi | 83% | 2300 fps | 99.9% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 44,179 psi | 73% | 2260 fps | 96.9% |
| Vihtavuori N530 | <<locked>> | 90% | 51,706 psi | 86% | 2306 fps | 99.8% |
| Vihtavuori N540 | <<locked>> | 96% | 52,330 psi | 87% | 2326 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 42,859 psi | 71% | 2264 fps | 96.5% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 45,411 psi | 75% | 2254 fps | 98.8% |
| Winchester 748 | <<locked>> | 88% | 51,126 psi | 85% | 2356 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 86% | 50,894 psi | 85% | 2346 fps | 99.6% |
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% | 38,798 psi | 64% | 2080 fps | 100% |
| Accurate 2200 | <<locked>> | 80% | 49,835 psi | 83% | 2297 fps | 98.5% |
| Accurate 2230 | <<locked>> | 80% | 50,314 psi | 84% | 2310 fps | 98.9% |
| Accurate 2460 | <<locked>> | 80% | 41,916 psi | 70% | 2165 fps | 99.9% |
| Accurate 2495 | <<locked>> | 80% | 31,212 psi | 52% | 2008 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 35,766 psi | 59% | 2110 fps | 99.1% |
| Accurate 2520 | <<locked>> | 80% | 35,766 psi | 59% | 2110 fps | 99.1% |
| Accurate 4064 | <<locked>> | 80% | 29,573 psi | 49% | 1991 fps | 98.6% |
| Accurate 4350 | <<locked>> | 98% | 38,247 psi | 64% | 2215 fps | 95.8% |
| Accurate LT-30 | <<locked>> | 80% | 47,297 psi | 79% | 2149 fps | 100% |
| Accurate LT-32 | <<locked>> | 80% | 47,645 psi | 79% | 2165 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 35,563 psi | 59% | 2083 fps | 96.3% |
| ADI AR 2208 | <<locked>> | 84% | 34,447 psi | 57% | 2044 fps | 95% |
| ADI AR 2219 | <<locked>> | 80% | 46,601 psi | 77% | 2241 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 80% | 37,550 psi | 62% | 2096 fps | 98% |
| Alliant AR-Comp | <<locked>> | 80% | 36,071 psi | 60% | 2100 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 43,120 psi | 72% | 2254 fps | 98.7% |
| Alliant Power Pro 2000-MR | 51 gr | 84% | 36,448 psi | 61% | 2175 fps | 95% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 29,225 psi | 49% | 1978 fps | 95.1% |
| Alliant Reloder-10x | <<locked>> | 80% | 44,077 psi | 73% | 2162 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 33,620 psi | 56% | 2064 fps | 95% |
| Alliant Reloder-16 | <<locked>> | 96% | 37,521 psi | 62% | 2178 fps | 95.1% |
| Alliant Reloder-17 | <<locked>> | 88% | 32,779 psi | 54% | 2110 fps | 95.3% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 45,977 psi | 76% | 2149 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 82% | 36,695 psi | 61% | 2123 fps | 95.3% |
| Bofors RP3 | <<locked>> | 82% | 30,110 psi | 50% | 2014 fps | 95.7% |
| Hodgdon Benchmark | <<locked>> | 80% | 39,740 psi | 66% | 2096 fps | 98.9% |
| Hodgdon BL-C2 | <<locked>> | 80% | 35,288 psi | 59% | 2110 fps | 98.1% |
| Hodgdon CFE223 | 49.7 gr | 80% | 38,769 psi | 64% | 2208 fps | 96.6% |
| Hodgdon H322 | <<locked>> | 80% | 39,697 psi | 66% | 2139 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 45,774 psi | 76% | 2241 fps | 100% |
| Hodgdon H380 | <<locked>> | 88% | 38,232 psi | 64% | 2149 fps | 95% |
| Hodgdon H4198 | <<locked>> | 80% | 48,950 psi | 81% | 2182 fps | 100% |
| Hodgdon H4895 | <<locked>> | 80% | 35,781 psi | 59% | 2093 fps | 97% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 31,966 psi | 53% | 2047 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 30,124 psi | 50% | 2018 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,585 psi | 43% | 1227 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 32,039 psi | 53% | 2005 fps | 95.6% |
| IMR 3031 | <<locked>> | 80% | 31,589 psi | 52% | 2044 fps | 99.8% |
| IMR 4064 | <<locked>> | 84% | 33,547 psi | 56% | 2021 fps | 95% |
| IMR 4198 | <<locked>> | 80% | 45,063 psi | 75% | 2133 fps | 100% |
| IMR 4895 | <<locked>> | 80% | 32,300 psi | 54% | 2051 fps | 95.3% |
| IMR 8208 XBR | <<locked>> | 80% | 37,550 psi | 62% | 2096 fps | 98% |
| Lovex D073.4 | <<locked>> | 80% | 43,685 psi | 73% | 2185 fps | 99.6% |
| Lovex D073.5 | <<locked>> | 80% | 41,553 psi | 69% | 2165 fps | 99.4% |
| Lovex D073.6 | <<locked>> | 80% | 33,547 psi | 56% | 2067 fps | 98.6% |
| Lovex S060 | <<locked>> | 80% | 36,709 psi | 61% | 2041 fps | 96.6% |
| Lovex S062 | <<locked>> | 80% | 31,473 psi | 52% | 1995 fps | 96.4% |
| Lovex S065 | <<locked>> | 98% | 44,208 psi | 73% | 2221 fps | 95.6% |
| Norma 200 | <<locked>> | 80% | 49,734 psi | 83% | 2211 fps | 100% |
| Norma 201 | <<locked>> | 80% | 34,896 psi | 58% | 2051 fps | 97.5% |
| Norma 202 | <<locked>> | 80% | 34,896 psi | 58% | 2064 fps | 99.3% |
| Norma 203B | <<locked>> | 82% | 32,953 psi | 55% | 2057 fps | 95.5% |
| Norma URP | <<locked>> | 98% | 39,189 psi | 65% | 2215 fps | 95.7% |
| Ramshot Big Game | <<locked>> | 84% | 34,780 psi | 58% | 2110 fps | 95.7% |
| Ramshot TAC | <<locked>> | 84% | 42,496 psi | 71% | 2182 fps | 95.3% |
| Ramshot Wild Boar | <<locked>> | 80% | 36,216 psi | 60% | 2106 fps | 96.4% |
| Ramshot X-Terminator | <<locked>> | 80% | 40,741 psi | 68% | 2136 fps | 97.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,759 psi | 43% | 1257 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 42,134 psi | 70% | 2169 fps | 99.6% |
| ReloadSwiss RS 50 | <<locked>> | 94% | 47,384 psi | 79% | 2267 fps | 95.5% |
| ReloadSwiss RS 52 | 48.3 gr | 82% | 34,693 psi | 58% | 2142 fps | 95.3% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 27,108 psi | 45% | 1975 fps | 95.1% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 38,551 psi | 64% | 2228 fps | 95.2% |
| Rottweil R 901 | <<locked>> | 80% | 38,551 psi | 64% | 2093 fps | 99.6% |
| Rottweil R 902 | <<locked>> | 80% | 33,315 psi | 55% | 2011 fps | 97% |
| Rottweil R 903 | <<locked>> | 84% | 30,385 psi | 50% | 2011 fps | 95.4% |
| Shooters World Long Rifle | <<locked>> | 98% | 44,208 psi | 73% | 2221 fps | 95.6% |
| Shooters World Match Rifle | <<locked>> | 80% | 33,547 psi | 56% | 2067 fps | 98.6% |
| Shooters World Precision | <<locked>> | 80% | 31,473 psi | 52% | 1995 fps | 96.4% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 44,556 psi | 74% | 2182 fps | 99% |
| SNPE Vectan SP 10 | <<locked>> | 80% | 46,934 psi | 78% | 2251 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 33,895 psi | 56% | 2096 fps | 95.4% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 44,730 psi | 74% | 2175 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 84% | 40,335 psi | 67% | 2156 fps | 95.4% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 34,127 psi | 57% | 2057 fps | 95.7% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 36,680 psi | 61% | 2024 fps | 99.5% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 29,921 psi | 50% | 1916 fps | 99% |
| Somchem S321 | <<locked>> | 80% | 39,987 psi | 66% | 2162 fps | 98.8% |
| Somchem S335 | <<locked>> | 80% | 36,114 psi | 60% | 2031 fps | 99.8% |
| Somchem S341 | <<locked>> | 80% | 34,954 psi | 58% | 2067 fps | 95.9% |
| Somchem S355 | <<locked>> | 84% | 31,560 psi | 52% | 2018 fps | 95.5% |
| Somchem S365 | <<locked>> | 92% | 29,167 psi | 48% | 2041 fps | 95.6% |
| Unknown powder | <<locked>> | 96% | 40,611 psi | 67% | 2221 fps | 95.3% |
| Vihtavuori N130 | <<locked>> | 80% | 41,669 psi | 69% | 2087 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 36,709 psi | 61% | 2028 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 31,836 psi | 53% | 2008 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 32,866 psi | 55% | 2011 fps | 99.2% |
| Vihtavuori N150 | <<locked>> | 82% | 28,108 psi | 47% | 1929 fps | 95.7% |
| Vihtavuori N160 | <<locked>> | 96% | 38,914 psi | 65% | 2172 fps | 95.5% |
| Vihtavuori N530 | <<locked>> | 80% | 37,347 psi | 62% | 2093 fps | 98.1% |
| Vihtavuori N540 | <<locked>> | 80% | 31,575 psi | 52% | 2001 fps | 98.5% |
| Vihtavuori N550 | <<locked>> | 96% | 37,855 psi | 63% | 2178 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 32,996 psi | 55% | 2034 fps | 95.4% |
| Winchester 748 | <<locked>> | 80% | 38,885 psi | 65% | 2175 fps | 99.1% |
| Winchester StaBALL Match | <<locked>> | 80% | 41,060 psi | 68% | 2201 fps | 98.3% |
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 114 powders for 9.3 x 66 Sako loaded with the .366 | 286gr | North Fork Semi Spitz. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 2,477 fps; across all powders the maximum-charge window runs from 1,375 fps to 2,477 fps. Accurate 4350 gives the best case fill at 100 %, and 114 of the 114 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (415 MPa), the top charges use 49–90 %, leaving at least 10 % headroom. The 286.0 gr projectile in 0.366" calls for a 1:16.5 twist; slower twists will usually not stabilise this weight. Accurate 4350, Alliant Reloder-16, Alliant Reloder-17 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 52, Hodgdon CFE223 rank at the top here: for 9.3 x 66 Sako with the .366 | 286gr | North Fork Semi Spitz they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 2700, Alliant Reloder-23, Bofors RP7 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.