Load Specifications
Bullet:.338 | 250gr | Barnes MRX BT
Bullet Manufacturer:Barnes
Bullet Weight:250 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:1:14.0
Load data in caliber 8.5 x 63 with .338 | 250gr | Barnes MRX BT bullet and 107 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 ReloadSwiss RS 52.
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>> | 88% | 55,477 psi | 89% | 2333 fps | 100% |
| Accurate 2460 | <<locked>> | 84% | 53,621 psi | 86% | 2359 fps | 100% |
| Accurate 2495 | <<locked>> | 94% | 56,072 psi | 90% | 2388 fps | 100% |
| Accurate 2520 | <<locked>> | 88% | 55,521 psi | 89% | 2415 fps | 100% |
| Accurate 2700 | <<locked>> | 92% | 53,505 psi | 86% | 2352 fps | 96.6% |
| Accurate 4064 | <<locked>> | 96% | 55,854 psi | 90% | 2428 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 48,138 psi | 77% | 2408 fps | 99% |
| Accurate LT-30 | <<locked>> | 82% | 55,172 psi | 88% | 2283 fps | 100% |
| Accurate LT-32 | <<locked>> | 82% | 55,593 psi | 89% | 2306 fps | 100% |
| ADI AR 2206H | <<locked>> | 90% | 54,665 psi | 88% | 2428 fps | 100% |
| ADI AR 2208 | <<locked>> | 96% | 55,390 psi | 89% | 2421 fps | 99.8% |
| ADI AR 2219 | <<locked>> | 82% | 56,072 psi | 90% | 2395 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 88% | 53,737 psi | 86% | 2382 fps | 100% |
| Alliant AR-Comp | <<locked>> | 88% | 53,838 psi | 86% | 2359 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 84% | 55,564 psi | 89% | 2474 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 92% | 53,882 psi | 86% | 2526 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 96% | 54,752 psi | 88% | 2438 fps | 100% |
| Alliant Reloder-10x | <<locked>> | 84% | 55,521 psi | 89% | 2336 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 94% | 55,709 psi | 89% | 2461 fps | 99.9% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 47,848 psi | 77% | 2418 fps | 99.2% |
| Alliant Reloder-17ᴾ | <<locked>> | 100% | 55,492 psi | 89% | 2549 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 33,475 psi | 54% | 2182 fps | 97.1% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 54,244 psi | 87% | 2290 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 90% | 54,302 psi | 87% | 2441 fps | 99.6% |
| Bofors RP3 | <<locked>> | 96% | 55,158 psi | 88% | 2454 fps | 100% |
| Bofors RP7ᴾ | <<locked>> | 100% | 55,854 psi | 90% | 2425 fps | 97.3% |
| Hodgdon Benchmark | <<locked>> | 88% | 55,956 psi | 90% | 2369 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 90% | 56,115 psi | 90% | 2454 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 86% | 54,752 psi | 88% | 2497 fps | 99.9% |
| Hodgdon H322 | <<locked>> | 84% | 54,781 psi | 88% | 2379 fps | 100% |
| Hodgdon H335 | <<locked>> | 84% | 55,535 psi | 89% | 2402 fps | 100% |
| Hodgdon H380 | <<locked>> | 94% | 52,982 psi | 85% | 2418 fps | 99.1% |
| Hodgdon H414ᴾ | <<locked>> | 100% | 51,909 psi | 83% | 2457 fps | 97.4% |
| Hodgdon H4350 | <<locked>> | 98% | 53,345 psi | 86% | 2428 fps | 96.2% |
| Hodgdon H4895 | <<locked>> | 90% | 55,172 psi | 88% | 2434 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 43,801 psi | 70% | 2313 fps | 99.4% |
| Hodgdon LEVERevolution | <<locked>> | 92% | 53,983 psi | 87% | 2464 fps | 100% |
| Hodgdon Superformanceᴾ | <<locked>> | 100% | 53,127 psi | 85% | 2490 fps | 97% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 34,824 psi | 56% | 1421 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 53,113 psi | 85% | 2395 fps | 100% |
| IMR 3031 | <<locked>> | 90% | 54,752 psi | 88% | 2415 fps | 100% |
| IMR 4064 | <<locked>> | 94% | 54,868 psi | 88% | 2405 fps | 99.9% |
| IMR 4166 Enduron | <<locked>> | 92% | 55,680 psi | 89% | 2392 fps | 97.8% |
| IMR 4198 | <<locked>> | 84% | 56,072 psi | 90% | 2300 fps | 100% |
| IMR 4350ᴾ | <<locked>> | 100% | 49,052 psi | 79% | 2352 fps | 96% |
| IMR 4451 Enduron | <<locked>> | 98% | 54,781 psi | 88% | 2411 fps | 97.6% |
| IMR 4831ᴾ | <<locked>> | 100% | 46,122 psi | 74% | 2362 fps | 98.8% |
| IMR 4895 | <<locked>> | 92% | 53,679 psi | 86% | 2441 fps | 99.9% |
| IMR 8208 XBR | <<locked>> | 88% | 53,737 psi | 86% | 2382 fps | 100% |
| Lovex D073.5 | <<locked>> | 84% | 53,592 psi | 86% | 2369 fps | 100% |
| Lovex D073.6 | <<locked>> | 90% | 53,650 psi | 86% | 2402 fps | 100% |
| Lovex S060 | <<locked>> | 90% | 54,708 psi | 88% | 2362 fps | 99.9% |
| Lovex S062 | <<locked>> | 94% | 54,505 psi | 87% | 2405 fps | 100% |
| Lovex S065ᴾ | <<locked>> | 100% | 53,243 psi | 85% | 2398 fps | 98.6% |
| Lovex S070ᴾ | <<locked>> | 100% | 50,517 psi | 81% | 2382 fps | 97.2% |
| Norma 201 | <<locked>> | 90% | 53,229 psi | 85% | 2375 fps | 100% |
| Norma 202 | <<locked>> | 90% | 53,563 psi | 86% | 2379 fps | 100% |
| Norma 203B | <<locked>> | 94% | 54,853 psi | 88% | 2448 fps | 100% |
| Norma URPᴾ | <<locked>> | 100% | 48,037 psi | 77% | 2402 fps | 98.9% |
| Ramshot Big Game | <<locked>> | 94% | 55,288 psi | 89% | 2474 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 47,413 psi | 76% | 2398 fps | 97.3% |
| Ramshot TAC | <<locked>> | 88% | 54,244 psi | 87% | 2402 fps | 98.8% |
| Ramshot Wild Boar | <<locked>> | 88% | 53,432 psi | 86% | 2418 fps | 99.9% |
| Ramshot X-Terminator | <<locked>> | 86% | 55,114 psi | 88% | 2392 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,244 psi | 57% | 1457 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 84% | 53,417 psi | 86% | 2365 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 94% | 53,722 psi | 86% | 2405 fps | 98.1% |
| ReloadSwiss RS 52 | <<locked>> | 92% | 55,825 psi | 90% | 2516 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 98% | 55,332 psi | 89% | 2546 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 47,935 psi | 77% | 2431 fps | 98.8% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 48,921 psi | 78% | 2454 fps | 98.5% |
| Rottweil R 901 | <<locked>> | 88% | 54,128 psi | 87% | 2359 fps | 100% |
| Rottweil R 902 | <<locked>> | 92% | 53,417 psi | 86% | 2372 fps | 100% |
| Rottweil R 903 | <<locked>> | 98% | 54,723 psi | 88% | 2441 fps | 100% |
| Rottweil R 907ᴾ | <<locked>> | 100% | 55,854 psi | 90% | 2425 fps | 97.3% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 53,243 psi | 85% | 2398 fps | 98.6% |
| Shooters World Match Rifle | <<locked>> | 90% | 53,650 psi | 86% | 2402 fps | 100% |
| Shooters World Precision | <<locked>> | 94% | 54,505 psi | 87% | 2405 fps | 100% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 50,517 psi | 81% | 2382 fps | 97.2% |
| Shooters World Tactical Rifle | <<locked>> | 82% | 53,272 psi | 85% | 2343 fps | 100% |
| SNPE Vectan SP 10 | <<locked>> | 82% | 56,130 psi | 90% | 2402 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 96% | 53,505 psi | 86% | 2457 fps | 99.9% |
| SNPE Vectan SP 3 | <<locked>> | 82% | 53,185 psi | 85% | 2316 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 90% | 55,811 psi | 89% | 2425 fps | 99.3% |
| SNPE Vectan SP 9 | <<locked>> | 92% | 56,275 psi | 90% | 2444 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 90% | 55,288 psi | 89% | 2323 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 96% | 55,100 psi | 88% | 2323 fps | 100% |
| SNPE Vectan Tubal 7000ᴾ | <<locked>> | 100% | 54,056 psi | 87% | 2362 fps | 97.5% |
| Somchem S321 | <<locked>> | 86% | 55,013 psi | 88% | 2415 fps | 100% |
| Somchem S335 | <<locked>> | 90% | 54,433 psi | 87% | 2326 fps | 100% |
| Somchem S341 | <<locked>> | 90% | 55,492 psi | 89% | 2421 fps | 99.9% |
| Somchem S355 | <<locked>> | 98% | 55,347 psi | 89% | 2438 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 42,714 psi | 68% | 2359 fps | 99.9% |
| Vihtavuori N130 | <<locked>> | 86% | 55,187 psi | 88% | 2293 fps | 100% |
| Vihtavuori N133 | <<locked>> | 90% | 55,376 psi | 89% | 2310 fps | 100% |
| Vihtavuori N135 | <<locked>> | 94% | 56,246 psi | 90% | 2379 fps | 100% |
| Vihtavuori N140 | <<locked>> | 92% | 54,143 psi | 87% | 2359 fps | 100% |
| Vihtavuori N150 | <<locked>> | 98% | 53,505 psi | 86% | 2382 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 50,676 psi | 81% | 2402 fps | 99.1% |
| Vihtavuori N530 | <<locked>> | 88% | 54,418 psi | 87% | 2385 fps | 100% |
| Vihtavuori N540 | <<locked>> | 94% | 55,579 psi | 89% | 2398 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 49,792 psi | 80% | 2411 fps | 98.9% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 35,491 psi | 57% | 2244 fps | 97% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 51,692 psi | 83% | 2392 fps | 100% |
| Winchester 748 | <<locked>> | 88% | 53,621 psi | 86% | 2425 fps | 100% |
| Winchester 760ᴾ | <<locked>> | 100% | 52,214 psi | 84% | 2461 fps | 97.5% |
| Winchester StaBALL Match | <<locked>> | 92% | 56,304 psi | 90% | 2454 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% | 43,149 psi | 69% | 2178 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 46,963 psi | 75% | 2274 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 35,302 psi | 57% | 2110 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 42,148 psi | 68% | 2238 fps | 100% |
| Accurate 2700 | <<locked>> | 88% | 46,963 psi | 75% | 2264 fps | 95.2% |
| Accurate 4064 | <<locked>> | 80% | 33,417 psi | 54% | 2100 fps | 99.8% |
| Accurate 4350 | <<locked>> | 90% | 33,997 psi | 55% | 2172 fps | 95.8% |
| Accurate LT-30 | <<locked>> | 80% | 51,822 psi | 83% | 2247 fps | 100% |
| Accurate LT-32 | <<locked>> | 80% | 52,243 psi | 84% | 2267 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 39,784 psi | 64% | 2201 fps | 98.5% |
| ADI AR 2208 | <<locked>> | 80% | 33,939 psi | 54% | 2077 fps | 96.2% |
| ADI AR 2219 | <<locked>> | 80% | 52,272 psi | 84% | 2349 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 80% | 41,916 psi | 67% | 2215 fps | 99.5% |
| Alliant AR-Comp | <<locked>> | 80% | 41,278 psi | 66% | 2201 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 48,791 psi | 78% | 2382 fps | 99.9% |
| Alliant Power Pro 2000-MR | 47.6 gr | 80% | 35,853 psi | 57% | 2218 fps | 96.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 32,880 psi | 53% | 2090 fps | 97.6% |
| Alliant Reloder-10x | <<locked>> | 80% | 48,863 psi | 78% | 2257 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 35,621 psi | 57% | 2146 fps | 97% |
| Alliant Reloder-16 | <<locked>> | 88% | 33,127 psi | 53% | 2139 fps | 95.2% |
| Alliant Reloder-17 | <<locked>> | 82% | 30,240 psi | 48% | 2103 fps | 95.9% |
| Alliant Reloder-23 | <<locked>> | 96% | 29,588 psi | 47% | 2090 fps | 95.3% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 50,923 psi | 82% | 2251 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 38,740 psi | 62% | 2205 fps | 97.3% |
| Bofors RP3 | <<locked>> | 80% | 32,198 psi | 52% | 2090 fps | 97.6% |
| Bofors RP7 | <<locked>> | 94% | 46,238 psi | 74% | 2290 fps | 95.3% |
| Hodgdon Benchmark | <<locked>> | 80% | 43,845 psi | 70% | 2205 fps | 99.9% |
| Hodgdon BL-C2 | <<locked>> | 80% | 40,001 psi | 64% | 2228 fps | 99.6% |
| Hodgdon CFE223 | <<locked>> | 80% | 44,092 psi | 71% | 2346 fps | 98.9% |
| Hodgdon H322 | <<locked>> | 80% | 47,863 psi | 77% | 2293 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 48,472 psi | 78% | 2316 fps | 100% |
| Hodgdon H380 | <<locked>> | 82% | 35,621 psi | 57% | 2139 fps | 95.6% |
| Hodgdon H414 | <<locked>> | 94% | 42,685 psi | 68% | 2316 fps | 95.3% |
| Hodgdon H4350 | <<locked>> | 96% | 50,111 psi | 80% | 2382 fps | 95.5% |
| Hodgdon H4895 | <<locked>> | 80% | 40,132 psi | 64% | 2211 fps | 98.9% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 28,253 psi | 45% | 2005 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 36,013 psi | 58% | 2185 fps | 98.5% |
| Hodgdon Superformance | <<locked>> | 96% | 45,934 psi | 74% | 2382 fps | 95.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 25,962 psi | 42% | 1270 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 38,551 psi | 62% | 2172 fps | 98.6% |
| IMR 3031 | <<locked>> | 80% | 39,378 psi | 63% | 2211 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 35,592 psi | 57% | 2106 fps | 97% |
| IMR 4166 Enduron | <<locked>> | 84% | 43,337 psi | 69% | 2211 fps | 95.2% |
| IMR 4198 | <<locked>> | 80% | 49,850 psi | 80% | 2228 fps | 100% |
| IMR 4350 | <<locked>> | 98% | 46,108 psi | 74% | 2310 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 90% | 42,931 psi | 69% | 2234 fps | 95% |
| IMR 4831 | <<locked>> | 90% | 33,054 psi | 53% | 2133 fps | 95.4% |
| IMR 4895 | <<locked>> | 80% | 36,477 psi | 58% | 2172 fps | 97.8% |
| IMR 8208 XBR | <<locked>> | 80% | 41,916 psi | 67% | 2215 fps | 99.5% |
| Lovex D073.5 | <<locked>> | 80% | 46,702 psi | 75% | 2280 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 38,058 psi | 61% | 2182 fps | 99.9% |
| Lovex S060 | <<locked>> | 80% | 40,480 psi | 65% | 2156 fps | 98.6% |
| Lovex S062 | <<locked>> | 80% | 35,215 psi | 56% | 2110 fps | 98.6% |
| Lovex S065 | <<locked>> | 90% | 39,262 psi | 63% | 2185 fps | 95.7% |
| Lovex S070 | <<locked>> | 94% | 41,872 psi | 67% | 2247 fps | 95.2% |
| Norma 201 | <<locked>> | 80% | 38,798 psi | 62% | 2162 fps | 99.2% |
| Norma 202 | <<locked>> | 80% | 38,972 psi | 62% | 2172 fps | 100% |
| Norma 203B | <<locked>> | 80% | 34,983 psi | 56% | 2136 fps | 97.4% |
| Norma URP | <<locked>> | 90% | 34,824 psi | 56% | 2175 fps | 95.8% |
| Ramshot Big Game | <<locked>> | 80% | 34,374 psi | 55% | 2142 fps | 96.9% |
| Ramshot Hunter | <<locked>> | 94% | 38,972 psi | 62% | 2254 fps | 95% |
| Ramshot TAC | <<locked>> | 80% | 41,742 psi | 67% | 2215 fps | 96.6% |
| Ramshot Wild Boar | <<locked>> | 80% | 40,785 psi | 65% | 2231 fps | 98.6% |
| Ramshot X-Terminator | <<locked>> | 80% | 45,281 psi | 73% | 2254 fps | 99.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 25,991 psi | 42% | 1296 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 46,876 psi | 75% | 2280 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 86% | 41,466 psi | 66% | 2221 fps | 95.5% |
| ReloadSwiss RS 52 | 46.1 gr | 80% | 36,782 psi | 59% | 2224 fps | 97.4% |
| ReloadSwiss RS 60 | 46.9 gr | 80% | 30,327 psi | 49% | 2113 fps | 98.4% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 34,098 psi | 55% | 2188 fps | 95.2% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 37,231 psi | 60% | 2244 fps | 95.2% |
| Rottweil R 901 | <<locked>> | 80% | 42,424 psi | 68% | 2195 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 36,970 psi | 59% | 2123 fps | 98.9% |
| Rottweil R 903 | <<locked>> | 80% | 30,240 psi | 48% | 2041 fps | 96.6% |
| Rottweil R 907 | <<locked>> | 94% | 46,238 psi | 74% | 2290 fps | 95.3% |
| Shooters World Long Rifle | <<locked>> | 90% | 39,262 psi | 63% | 2185 fps | 95.7% |
| Shooters World Match Rifle | <<locked>> | 80% | 38,058 psi | 61% | 2182 fps | 99.9% |
| Shooters World Precision | <<locked>> | 80% | 35,215 psi | 56% | 2110 fps | 98.6% |
| Shooters World SW4350 | <<locked>> | 94% | 41,872 psi | 67% | 2247 fps | 95.2% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 49,705 psi | 80% | 2300 fps | 99.9% |
| SNPE Vectan SP 10 | <<locked>> | 80% | 52,489 psi | 84% | 2359 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 31,430 psi | 50% | 2083 fps | 96% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 49,835 psi | 80% | 2277 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 39,494 psi | 63% | 2185 fps | 96.6% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 38,203 psi | 61% | 2175 fps | 98.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 40,480 psi | 65% | 2126 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 33,286 psi | 53% | 2014 fps | 99.9% |
| SNPE Vectan Tubal 7000 | <<locked>> | 94% | 44,063 psi | 71% | 2228 fps | 95.5% |
| Somchem S321 | <<locked>> | 80% | 44,933 psi | 72% | 2280 fps | 99.9% |
| Somchem S335 | <<locked>> | 80% | 40,001 psi | 64% | 2129 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 39,450 psi | 63% | 2192 fps | 98.3% |
| Somchem S355 | <<locked>> | 80% | 31,343 psi | 50% | 2051 fps | 96.7% |
| Somchem S365 | <<locked>> | 84% | 25,483 psi | 41% | 1985 fps | 95.2% |
| Vihtavuori N130 | <<locked>> | 80% | 45,948 psi | 74% | 2182 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 40,741 psi | 65% | 2123 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 35,998 psi | 58% | 2110 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 36,985 psi | 59% | 2119 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 29,733 psi | 48% | 2001 fps | 97.6% |
| Vihtavuori N160 | <<locked>> | 88% | 34,214 psi | 55% | 2129 fps | 95.4% |
| Vihtavuori N530 | <<locked>> | 80% | 41,843 psi | 67% | 2208 fps | 99.6% |
| Vihtavuori N540 | <<locked>> | 80% | 35,317 psi | 57% | 2110 fps | 99.8% |
| Vihtavuori N550 | <<locked>> | 88% | 33,446 psi | 54% | 2133 fps | 95% |
| Vihtavuori N555 | <<locked>> | 96% | 31,372 psi | 50% | 2156 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 28,471 psi | 46% | 1982 fps | 95.2% |
| Winchester 748 | <<locked>> | 80% | 41,017 psi | 66% | 2247 fps | 99.8% |
| Winchester 760 | <<locked>> | 94% | 42,685 psi | 68% | 2316 fps | 95.3% |
| Winchester StaBALL Match | <<locked>> | 80% | 37,449 psi | 60% | 2178 fps | 98.5% |
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 107 powders for 8.5 x 63 loaded with the .338 | 250gr | Barnes MRX BT. Alliant Reloder-17 delivers the highest muzzle velocity at 2,549 fps; across all powders the maximum-charge window runs from 1,421 fps to 2,549 fps. Accurate 4350 gives the best case fill at 100 %, and 107 of the 107 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 250.0 gr projectile in 0.338" calls for a 1:14.0 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 60, ReloadSwiss RS 52 rank at the top here: for 8.5 x 63 with the .338 | 250gr | Barnes MRX BT they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.