Load Specifications
Bullet:.338 | 275gr | Speer SSP
Bullet Manufacturer:Speer
Bullet Weight:275 gr
Bullet Diameter:0.338"
Bullet Length:<<locked>>
Caliber:8.5 x 63 load data
Case Length (l3):2.48"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:75.5 Grains of Water
Primer Size:Large Rifle (LR)
Barrel Length:23.62"
Max. allowed Pressure:62,366 psi
Recommended Twist Rate:1:16.0
Load data in caliber 8.5 x 63 with .338 | 275gr | Speer SSP bullet and 106 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, Hodgdon Superformance 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: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 84% | 55,376 psi | 89% | 2218 fps | 100% |
| Accurate 2495 | <<locked>> | 88% | 53,896 psi | 86% | 2244 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 54,143 psi | 87% | 2290 fps | 100% |
| Accurate 2520 | <<locked>> | 84% | 54,143 psi | 87% | 2290 fps | 100% |
| Accurate 2700 | <<locked>> | 92% | 53,954 psi | 87% | 2260 fps | 98% |
| Accurate 3100ᴾ | <<locked>> | 100% | 40,640 psi | 65% | 2178 fps | 97.3% |
| Accurate 4064 | <<locked>> | 90% | 54,099 psi | 87% | 2287 fps | 100% |
| Accurate 4350 | <<locked>> | 98% | 53,403 psi | 86% | 2365 fps | 99.9% |
| ADI AR 2206H | <<locked>> | 86% | 54,491 psi | 87% | 2313 fps | 100% |
| ADI AR 2208 | <<locked>> | 92% | 55,405 psi | 89% | 2316 fps | 100% |
| ADI AR 2209ᴾ | <<locked>> | 100% | 48,646 psi | 78% | 2303 fps | 96.1% |
| ADI Benchmark 8208 | <<locked>> | 84% | 53,432 psi | 86% | 2270 fps | 100% |
| Alliant AR-Comp | <<locked>> | 84% | 54,549 psi | 87% | 2244 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 88% | 53,708 psi | 86% | 2415 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 92% | 55,463 psi | 89% | 2333 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 90% | 56,014 psi | 90% | 2352 fps | 100% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 54,578 psi | 88% | 2408 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 96% | 55,811 psi | 89% | 2441 fps | 100% |
| Alliant Reloder-19ᴾ | <<locked>> | 100% | 47,500 psi | 76% | 2293 fps | 96.1% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 39,146 psi | 63% | 2208 fps | 99.6% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 43,294 psi | 69% | 2339 fps | 99.1% |
| Baschieri & Pellagri 107 | <<locked>> | 86% | 53,911 psi | 86% | 2329 fps | 100% |
| Bofors RP3 | <<locked>> | 92% | 55,927 psi | 90% | 2346 fps | 100% |
| Bofors RP7 | <<locked>> | 96% | 55,912 psi | 90% | 2326 fps | 98.5% |
| Hodgdon Benchmark | <<locked>> | 84% | 55,245 psi | 89% | 2251 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 86% | 56,202 psi | 90% | 2339 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 82% | 54,491 psi | 87% | 2379 fps | 100% |
| Hodgdon H322 | <<locked>> | 82% | 53,519 psi | 86% | 2251 fps | 100% |
| Hodgdon H380 | <<locked>> | 90% | 53,330 psi | 86% | 2316 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 94% | 54,259 psi | 87% | 2385 fps | 98.9% |
| Hodgdon H4350 | <<locked>> | 98% | 54,839 psi | 88% | 2349 fps | 97.9% |
| Hodgdon H4895 | <<locked>> | 86% | 55,071 psi | 88% | 2323 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 50,778 psi | 81% | 2303 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 90% | 54,302 psi | 87% | 2352 fps | 100% |
| Hodgdon Superformance | <<locked>> | 96% | 52,939 psi | 85% | 2395 fps | 98.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,534 psi | 57% | 1371 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 55,042 psi | 88% | 2310 fps | 100% |
| IMR 3031 | <<locked>> | 88% | 53,461 psi | 86% | 2280 fps | 100% |
| IMR 4064 | <<locked>> | 92% | 54,143 psi | 87% | 2290 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 92% | 53,679 psi | 86% | 2270 fps | 98.6% |
| IMR 4350ᴾ | <<locked>> | 100% | 56,014 psi | 90% | 2349 fps | 98.6% |
| IMR 4451 Enduron | <<locked>> | 94% | 54,404 psi | 87% | 2310 fps | 98.7% |
| IMR 4831ᴾ | <<locked>> | 100% | 47,979 psi | 77% | 2283 fps | 99.7% |
| IMR 4895 | <<locked>> | 88% | 53,795 psi | 86% | 2333 fps | 100% |
| IMR 8208 XBR | <<locked>> | 84% | 53,432 psi | 86% | 2270 fps | 100% |
| Lovex D073.6 | <<locked>> | 86% | 54,143 psi | 87% | 2290 fps | 100% |
| Lovex S060 | <<locked>> | 86% | 53,954 psi | 87% | 2251 fps | 100% |
| Lovex S062 | <<locked>> | 90% | 54,824 psi | 88% | 2297 fps | 100% |
| Lovex S065 | <<locked>> | 96% | 53,708 psi | 86% | 2303 fps | 99.5% |
| Lovex S070 | <<locked>> | 98% | 54,679 psi | 88% | 2336 fps | 99% |
| Norma 201 | <<locked>> | 86% | 53,272 psi | 85% | 2267 fps | 100% |
| Norma 202 | <<locked>> | 86% | 53,809 psi | 86% | 2267 fps | 100% |
| Norma 203B | <<locked>> | 90% | 55,172 psi | 88% | 2339 fps | 100% |
| Norma 204 | <<locked>> | 98% | 53,055 psi | 85% | 2349 fps | 97% |
| Norma MRPᴾ | <<locked>> | 100% | 43,468 psi | 70% | 2306 fps | 96.8% |
| Norma URPᴾ | <<locked>> | 100% | 55,927 psi | 90% | 2398 fps | 100% |
| Ramshot Big Game | <<locked>> | 90% | 55,419 psi | 89% | 2362 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 54,636 psi | 88% | 2398 fps | 99.4% |
| Ramshot TAC | <<locked>> | 84% | 53,505 psi | 86% | 2293 fps | 99.5% |
| Ramshot Wild Boar | <<locked>> | 84% | 53,055 psi | 85% | 2303 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 82% | 54,317 psi | 87% | 2274 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 36,114 psi | 58% | 1404 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 82% | 56,333 psi | 90% | 2290 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 90% | 53,766 psi | 86% | 2306 fps | 99.1% |
| ReloadSwiss RS 52 | <<locked>> | 86% | 52,881 psi | 85% | 2365 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 94% | 55,622 psi | 89% | 2434 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 98% | 52,924 psi | 85% | 2388 fps | 99.9% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 56,318 psi | 90% | 2461 fps | 100% |
| Rottweil R 901 | <<locked>> | 84% | 54,360 psi | 87% | 2244 fps | 100% |
| Rottweil R 902 | <<locked>> | 88% | 53,722 psi | 86% | 2264 fps | 100% |
| Rottweil R 903 | <<locked>> | 94% | 55,767 psi | 89% | 2339 fps | 100% |
| Rottweil R 905ᴾ | <<locked>> | 100% | 46,195 psi | 74% | 2280 fps | 96.1% |
| Rottweil R 907 | <<locked>> | 96% | 55,912 psi | 90% | 2326 fps | 98.5% |
| Shooters World Long Rifle | <<locked>> | 96% | 53,708 psi | 86% | 2303 fps | 99.5% |
| Shooters World Match Rifle | <<locked>> | 86% | 54,143 psi | 87% | 2290 fps | 100% |
| Shooters World Precision | <<locked>> | 90% | 54,824 psi | 88% | 2297 fps | 100% |
| Shooters World SW4350 | <<locked>> | 98% | 54,679 psi | 88% | 2336 fps | 99% |
| SNPE Vectan SP 11 | <<locked>> | 92% | 53,722 psi | 86% | 2349 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 86% | 55,637 psi | 89% | 2320 fps | 99.8% |
| SNPE Vectan SP 9 | <<locked>> | 88% | 56,246 psi | 90% | 2333 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 86% | 54,824 psi | 88% | 2208 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 92% | 54,984 psi | 88% | 2211 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 96% | 53,896 psi | 86% | 2264 fps | 98.6% |
| SNPE Vectan Tubal 8000ᴾ | <<locked>> | 100% | 45,788 psi | 73% | 2274 fps | 95.9% |
| Somchem S321 | <<locked>> | 82% | 54,607 psi | 88% | 2300 fps | 100% |
| Somchem S335 | <<locked>> | 86% | 54,099 psi | 87% | 2211 fps | 100% |
| Somchem S341 | <<locked>> | 86% | 54,984 psi | 88% | 2306 fps | 100% |
| Somchem S355 | <<locked>> | 94% | 56,043 psi | 90% | 2336 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 50,227 psi | 81% | 2356 fps | 100% |
| Somchem S385ᴾ | <<locked>> | 100% | 46,673 psi | 75% | 2260 fps | 97% |
| Unknown powder | <<locked>> | 96% | 53,534 psi | 86% | 2359 fps | 99.7% |
| Vihtavuori N130 | <<locked>> | 82% | 54,592 psi | 88% | 2172 fps | 100% |
| Vihtavuori N133 | <<locked>> | 86% | 55,085 psi | 88% | 2195 fps | 100% |
| Vihtavuori N135 | <<locked>> | 88% | 53,621 psi | 86% | 2231 fps | 100% |
| Vihtavuori N140 | <<locked>> | 88% | 54,302 psi | 87% | 2247 fps | 100% |
| Vihtavuori N150 | <<locked>> | 94% | 54,041 psi | 87% | 2277 fps | 100% |
| Vihtavuori N160 | <<locked>> | 98% | 55,085 psi | 88% | 2349 fps | 99.9% |
| Vihtavuori N530 | <<locked>> | 84% | 54,012 psi | 87% | 2270 fps | 100% |
| Vihtavuori N540 | <<locked>> | 90% | 55,622 psi | 89% | 2287 fps | 100% |
| Vihtavuori N550 | <<locked>> | 98% | 53,896 psi | 86% | 2359 fps | 99.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 42,772 psi | 69% | 2267 fps | 99.5% |
| Winchester 6.5 StaBALL | <<locked>> | 98% | 54,940 psi | 88% | 2329 fps | 100% |
| Winchester 748 | <<locked>> | 82% | 54,389 psi | 87% | 2320 fps | 100% |
| Winchester 760 | <<locked>> | 94% | 54,259 psi | 87% | 2385 fps | 98.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 34,882 psi | 56% | 2218 fps | 99.7% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 48,733 psi | 78% | 2277 fps | 96.1% |
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% | 49,037 psi | 79% | 2146 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 41,742 psi | 67% | 2093 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 47,152 psi | 76% | 2205 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 47,152 psi | 76% | 2205 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 41,756 psi | 67% | 2087 fps | 95.4% |
| Accurate 3100 | <<locked>> | 94% | 33,286 psi | 53% | 2047 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 39,465 psi | 63% | 2093 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 28,863 psi | 46% | 1962 fps | 95.3% |
| ADI AR 2206H | <<locked>> | 80% | 45,107 psi | 72% | 2185 fps | 99.8% |
| ADI AR 2208 | <<locked>> | 80% | 38,508 psi | 62% | 2070 fps | 98.7% |
| ADI AR 2209 | <<locked>> | 98% | 45,788 psi | 73% | 2257 fps | 95.4% |
| ADI Benchmark 8208 | <<locked>> | 80% | 47,195 psi | 76% | 2188 fps | 100% |
| Alliant AR-Comp | <<locked>> | 80% | 47,688 psi | 76% | 2165 fps | 100% |
| Alliant Power Pro 2000-MR | 48.9 gr | 80% | 41,002 psi | 66% | 2224 fps | 99.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 38,203 psi | 61% | 2090 fps | 99.6% |
| Alliant Reloder-15 | <<locked>> | 80% | 40,843 psi | 65% | 2139 fps | 99.2% |
| Alliant Reloder-16 | <<locked>> | 80% | 29,675 psi | 48% | 1972 fps | 95.4% |
| Alliant Reloder-17 | 48.2 gr | 80% | 32,866 psi | 53% | 2073 fps | 98.5% |
| Alliant Reloder-19 | <<locked>> | 98% | 44,788 psi | 72% | 2251 fps | 95.4% |
| Alliant Reloder-23 | <<locked>> | 86% | 25,672 psi | 41% | 1903 fps | 95.1% |
| Alliant Reloder-26 | <<locked>> | 90% | 30,951 psi | 50% | 2087 fps | 95.1% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 44,251 psi | 71% | 2195 fps | 99.3% |
| Bofors RP3 | <<locked>> | 80% | 37,695 psi | 60% | 2093 fps | 99.6% |
| Bofors RP7 | <<locked>> | 86% | 41,292 psi | 66% | 2116 fps | 95.6% |
| Hodgdon Benchmark | <<locked>> | 80% | 48,936 psi | 78% | 2175 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 45,992 psi | 74% | 2211 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 50,981 psi | 82% | 2336 fps | 100% |
| Hodgdon H322 | <<locked>> | 80% | 50,328 psi | 81% | 2211 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 38,508 psi | 62% | 2096 fps | 97.8% |
| Hodgdon H414 | <<locked>> | 84% | 38,754 psi | 62% | 2149 fps | 95.7% |
| Hodgdon H4350 | <<locked>> | 90% | 43,265 psi | 69% | 2182 fps | 95.4% |
| Hodgdon H4895 | <<locked>> | 80% | 45,556 psi | 73% | 2195 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 27,151 psi | 44% | 1893 fps | 96.3% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 39,146 psi | 63% | 2139 fps | 99.7% |
| Hodgdon Superformance | 56 gr | 88% | 40,045 psi | 64% | 2195 fps | 95.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,629 psi | 43% | 1224 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 40,567 psi | 65% | 2106 fps | 99.6% |
| IMR 3031 | <<locked>> | 80% | 41,655 psi | 67% | 2129 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 37,855 psi | 61% | 2051 fps | 98.7% |
| IMR 4166 Enduron | <<locked>> | 80% | 37,666 psi | 60% | 2024 fps | 95.1% |
| IMR 4350 | <<locked>> | 90% | 41,205 psi | 66% | 2139 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 82% | 37,898 psi | 61% | 2054 fps | 95.1% |
| IMR 4831 | <<locked>> | 84% | 29,211 psi | 47% | 1952 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 41,858 psi | 67% | 2162 fps | 99.6% |
| IMR 8208 XBR | <<locked>> | 80% | 47,195 psi | 76% | 2188 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 44,324 psi | 71% | 2169 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 45,252 psi | 73% | 2133 fps | 99.8% |
| Lovex S062 | <<locked>> | 80% | 40,393 psi | 65% | 2100 fps | 99.9% |
| Lovex S065 | <<locked>> | 80% | 33,112 psi | 53% | 1972 fps | 95.2% |
| Lovex S070 | <<locked>> | 86% | 37,710 psi | 60% | 2080 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 44,237 psi | 71% | 2146 fps | 100% |
| Norma 202 | <<locked>> | 80% | 44,657 psi | 72% | 2149 fps | 100% |
| Norma 203B | <<locked>> | 80% | 40,219 psi | 64% | 2129 fps | 99.4% |
| Norma 204 | <<locked>> | 94% | 46,383 psi | 74% | 2254 fps | 95.6% |
| Norma MRP | <<locked>> | 96% | 38,087 psi | 61% | 2205 fps | 95% |
| Norma URP | <<locked>> | 80% | 29,472 psi | 47% | 1962 fps | 95.2% |
| Ramshot Big Game | <<locked>> | 80% | 39,668 psi | 64% | 2142 fps | 99.2% |
| Ramshot Hunter | <<locked>> | 86% | 34,954 psi | 56% | 2087 fps | 95.3% |
| Ramshot TAC | <<locked>> | 80% | 46,992 psi | 75% | 2201 fps | 98.8% |
| Ramshot Wild Boar | <<locked>> | 80% | 46,673 psi | 75% | 2218 fps | 99.9% |
| Ramshot X-Terminator | <<locked>> | 80% | 50,792 psi | 81% | 2231 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,006 psi | 43% | 1253 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 52,823 psi | 85% | 2247 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 38,972 psi | 62% | 2083 fps | 96.3% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 43,004 psi | 69% | 2224 fps | 99.5% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 34,983 psi | 56% | 2126 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 30,690 psi | 49% | 2018 fps | 95.5% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 33,083 psi | 53% | 2070 fps | 95.5% |
| Rottweil R 901 | <<locked>> | 80% | 48,254 psi | 77% | 2169 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 42,293 psi | 68% | 2110 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 35,534 psi | 57% | 2047 fps | 99.1% |
| Rottweil R 905 | <<locked>> | 98% | 43,149 psi | 69% | 2231 fps | 95.2% |
| Rottweil R 907 | <<locked>> | 86% | 41,292 psi | 66% | 2116 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 33,112 psi | 53% | 1972 fps | 95.2% |
| Shooters World Match Rifle | <<locked>> | 80% | 44,324 psi | 71% | 2169 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 40,393 psi | 65% | 2100 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 86% | 37,710 psi | 60% | 2080 fps | 95.5% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 36,390 psi | 58% | 2090 fps | 98.7% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 45,469 psi | 73% | 2185 fps | 99% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 43,584 psi | 70% | 2165 fps | 99.7% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 45,571 psi | 73% | 2096 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 37,985 psi | 61% | 1995 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 39,160 psi | 63% | 2054 fps | 95.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 42,772 psi | 69% | 2224 fps | 95.1% |
| Somchem S321 | <<locked>> | 80% | 50,952 psi | 82% | 2254 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 45,165 psi | 72% | 2100 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 45,034 psi | 72% | 2178 fps | 99.8% |
| Somchem S355 | <<locked>> | 80% | 36,347 psi | 58% | 2051 fps | 99.1% |
| Somchem S365 | <<locked>> | 80% | 26,498 psi | 42% | 1929 fps | 97.6% |
| Somchem S385 | <<locked>> | 96% | 41,060 psi | 66% | 2175 fps | 95.6% |
| Unknown powder | <<locked>> | 80% | 32,039 psi | 51% | 2008 fps | 95.5% |
| Vihtavuori N130 | <<locked>> | 80% | 51,387 psi | 82% | 2139 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 45,934 psi | 74% | 2090 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 41,713 psi | 67% | 2087 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 42,192 psi | 68% | 2096 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 34,548 psi | 55% | 1998 fps | 99.6% |
| Vihtavuori N160 | <<locked>> | 80% | 30,763 psi | 49% | 1965 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 47,297 psi | 76% | 2185 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 40,567 psi | 65% | 2093 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 30,168 psi | 48% | 1965 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 86% | 27,325 psi | 44% | 1965 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 30,545 psi | 49% | 1946 fps | 97.8% |
| Winchester 748 | <<locked>> | 80% | 50,618 psi | 81% | 2274 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 38,754 psi | 62% | 2149 fps | 95.7% |
| Winchester StaBALL HD | <<locked>> | 90% | 25,585 psi | 41% | 1962 fps | 95.3% |
| Winchester Supreme 780 | <<locked>> | 98% | 45,455 psi | 73% | 2228 fps | 95.3% |
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 121 powders for 8.5 x 63 loaded with the .338 | 275gr | Speer SSP. ReloadSwiss RS 70 delivers the highest muzzle velocity at 2,461 fps; across all powders the maximum-charge window runs from 1,371 fps to 2,461 fps. Accurate 3100 gives the best case fill at 100 %, and 121 of the 121 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (430 MPa), the top charges use 54–90 %, leaving at least 10 % headroom. The 275.0 gr projectile in 0.338" calls for a 1:16.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2209, 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 Power Pro 2000-MR, Hodgdon Superformance, Alliant Reloder-17 rank at the top here: for 8.5 x 63 with the .338 | 275gr | Speer SSP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, ADI AR 2213, Alliant Reloder-22, Bofors RP15 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.