Load Specifications
Bullet Manufacturer:Speer
Bullet Weight:250 gr
Bullet Diameter:0.338"
Bullet Length:<<locked>>
Caliber:.338 RCM load data
Case Length (l3):2"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:71 Grains of Water
Primer Size:Large Rifle (LR)
Barrel Length:24"
Max. allowed Pressure:62,366 psi
Recommended Twist Rate:1:6.0
Load data in caliber .338 RCM with .338 | 250gr | Speer Grand Slam bullet and 105 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 Power Pro 2000-MR 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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 86% | 53,969 psi | 87% | 2323 fps | 100% |
| Accurate 2460 | <<locked>> | 84% | 55,912 psi | 90% | 2392 fps | 100% |
| Accurate 2495 | <<locked>> | 92% | 55,245 psi | 89% | 2385 fps | 100% |
| Accurate 2520 | <<locked>> | 86% | 53,998 psi | 87% | 2405 fps | 100% |
| Accurate 2700 | <<locked>> | 92% | 55,288 psi | 89% | 2388 fps | 97.1% |
| Accurate 4064 | <<locked>> | 94% | 54,984 psi | 88% | 2425 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 50,386 psi | 81% | 2451 fps | 99.4% |
| ADI AR 2206H | <<locked>> | 90% | 56,333 psi | 90% | 2457 fps | 100% |
| ADI AR 2208 | <<locked>> | 94% | 53,824 psi | 86% | 2411 fps | 99.8% |
| ADI Benchmark 8208 | <<locked>> | 88% | 55,622 psi | 89% | 2415 fps | 100% |
| Alliant AR-Comp | <<locked>> | 88% | 55,709 psi | 89% | 2385 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 82% | 53,896 psi | 86% | 2461 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 92% | 55,637 psi | 89% | 2562 fps | 99.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 94% | 53,374 psi | 86% | 2431 fps | 100% |
| Alliant Reloder-10x | <<locked>> | 82% | 53,940 psi | 86% | 2326 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 92% | 54,041 psi | 87% | 2451 fps | 99.9% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 49,530 psi | 79% | 2457 fps | 99.5% |
| Alliant Reloder-17 | <<locked>> | 98% | 53,592 psi | 86% | 2536 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 35,041 psi | 56% | 2231 fps | 97.9% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 38,580 psi | 62% | 2356 fps | 96.7% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 55,622 psi | 89% | 2313 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 90% | 55,825 psi | 90% | 2474 fps | 99.8% |
| Bofors RP3 | <<locked>> | 94% | 53,650 psi | 86% | 2444 fps | 100% |
| Bofors RP7 | <<locked>> | 98% | 54,331 psi | 87% | 2418 fps | 97.3% |
| Hodgdon Benchmark | <<locked>> | 86% | 54,201 psi | 87% | 2359 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 88% | 54,433 psi | 87% | 2444 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 84% | 52,678 psi | 84% | 2484 fps | 99.8% |
| Hodgdon H322 | <<locked>> | 84% | 56,130 psi | 90% | 2405 fps | 100% |
| Hodgdon H335 | <<locked>> | 82% | 53,534 psi | 86% | 2388 fps | 100% |
| Hodgdon H380 | <<locked>> | 94% | 54,984 psi | 88% | 2457 fps | 99.5% |
| Hodgdon H414ᴾ | <<locked>> | 100% | 53,795 psi | 86% | 2497 fps | 97.9% |
| Hodgdon H4350 | <<locked>> | 98% | 55,114 psi | 88% | 2464 fps | 96.8% |
| Hodgdon H4895 | <<locked>> | 88% | 53,563 psi | 86% | 2425 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 45,585 psi | 73% | 2352 fps | 99.7% |
| Hodgdon LEVERevolution | <<locked>> | 92% | 55,608 psi | 89% | 2493 fps | 100% |
| Hodgdon Superformanceᴾ | <<locked>> | 100% | 55,056 psi | 88% | 2533 fps | 97.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,128 psi | 56% | 1434 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 54,621 psi | 88% | 2425 fps | 100% |
| IMR 3031 | <<locked>> | 88% | 53,069 psi | 85% | 2405 fps | 100% |
| IMR 4064 | <<locked>> | 92% | 53,374 psi | 86% | 2398 fps | 99.8% |
| IMR 4166 Enduron | <<locked>> | 90% | 53,795 psi | 86% | 2382 fps | 97.7% |
| IMR 4198 | <<locked>> | 82% | 54,128 psi | 87% | 2287 fps | 100% |
| IMR 4350ᴾ | <<locked>> | 100% | 50,720 psi | 81% | 2392 fps | 96.7% |
| IMR 4451 Enduron | <<locked>> | 98% | 56,130 psi | 90% | 2441 fps | 98% |
| IMR 4831ᴾ | <<locked>> | 100% | 48,109 psi | 77% | 2402 fps | 99.2% |
| IMR 4895 | <<locked>> | 92% | 55,376 psi | 89% | 2477 fps | 100% |
| IMR 8208 XBR | <<locked>> | 88% | 55,622 psi | 89% | 2415 fps | 100% |
| Lovex D073.5 | <<locked>> | 84% | 55,535 psi | 89% | 2402 fps | 100% |
| Lovex D073.6 | <<locked>> | 90% | 55,593 psi | 89% | 2434 fps | 100% |
| Lovex S060 | <<locked>> | 90% | 56,202 psi | 90% | 2392 fps | 100% |
| Lovex S062 | <<locked>> | 94% | 56,246 psi | 90% | 2434 fps | 100% |
| Lovex S065ᴾ | <<locked>> | 100% | 55,187 psi | 88% | 2438 fps | 99% |
| Lovex S070ᴾ | <<locked>> | 100% | 52,460 psi | 84% | 2421 fps | 97.8% |
| Norma 201 | <<locked>> | 90% | 55,085 psi | 88% | 2408 fps | 100% |
| Norma 202 | <<locked>> | 90% | 55,608 psi | 89% | 2411 fps | 100% |
| Norma 203B | <<locked>> | 92% | 53,200 psi | 85% | 2438 fps | 100% |
| Norma URPᴾ | <<locked>> | 100% | 49,966 psi | 80% | 2441 fps | 99.3% |
| Ramshot Big Game | <<locked>> | 92% | 53,519 psi | 86% | 2464 fps | 99.9% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 49,139 psi | 79% | 2438 fps | 97.9% |
| Ramshot TAC | <<locked>> | 88% | 55,709 psi | 89% | 2434 fps | 99.1% |
| Ramshot Wild Boar | <<locked>> | 88% | 55,274 psi | 89% | 2454 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 84% | 53,113 psi | 85% | 2375 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,621 psi | 57% | 1470 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 84% | 55,027 psi | 88% | 2395 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 94% | 55,579 psi | 89% | 2441 fps | 98.5% |
| ReloadSwiss RS 52 | <<locked>> | 90% | 54,056 psi | 87% | 2507 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 96% | 53,447 psi | 86% | 2536 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 49,879 psi | 80% | 2470 fps | 99.2% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 50,604 psi | 81% | 2493 fps | 98.9% |
| Rottweil R 901 | <<locked>> | 88% | 56,246 psi | 90% | 2392 fps | 100% |
| Rottweil R 902 | <<locked>> | 92% | 55,288 psi | 89% | 2405 fps | 100% |
| Rottweil R 903 | <<locked>> | 96% | 53,519 psi | 86% | 2434 fps | 100% |
| Rottweil R 907 | <<locked>> | 98% | 54,331 psi | 87% | 2418 fps | 97.3% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 55,187 psi | 88% | 2438 fps | 99% |
| Shooters World Match Rifle | <<locked>> | 90% | 55,593 psi | 89% | 2434 fps | 100% |
| Shooters World Precision | <<locked>> | 94% | 56,246 psi | 90% | 2434 fps | 100% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 52,460 psi | 84% | 2421 fps | 97.8% |
| Shooters World Tactical Rifle | <<locked>> | 82% | 54,839 psi | 88% | 2375 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 96% | 55,085 psi | 88% | 2490 fps | 100% |
| SNPE Vectan SP 3 | <<locked>> | 82% | 54,911 psi | 88% | 2346 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 88% | 54,099 psi | 87% | 2415 fps | 99.3% |
| SNPE Vectan SP 9 | <<locked>> | 90% | 54,462 psi | 87% | 2434 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 88% | 53,780 psi | 86% | 2316 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 94% | 53,490 psi | 86% | 2316 fps | 100% |
| SNPE Vectan Tubal 7000ᴾ | <<locked>> | 100% | 55,709 psi | 89% | 2395 fps | 97.9% |
| Somchem S321 | <<locked>> | 84% | 53,142 psi | 85% | 2405 fps | 100% |
| Somchem S335 | <<locked>> | 90% | 56,115 psi | 90% | 2352 fps | 100% |
| Somchem S341 | <<locked>> | 88% | 53,447 psi | 86% | 2405 fps | 99.9% |
| Somchem S355 | <<locked>> | 96% | 54,027 psi | 87% | 2434 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 44,585 psi | 71% | 2398 fps | 100% |
| Vihtavuori N130 | <<locked>> | 84% | 53,505 psi | 86% | 2283 fps | 100% |
| Vihtavuori N133 | <<locked>> | 88% | 53,925 psi | 86% | 2303 fps | 100% |
| Vihtavuori N135 | <<locked>> | 92% | 54,897 psi | 88% | 2372 fps | 100% |
| Vihtavuori N140 | <<locked>> | 92% | 55,753 psi | 89% | 2388 fps | 100% |
| Vihtavuori N150 | <<locked>> | 98% | 55,463 psi | 89% | 2415 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 52,562 psi | 84% | 2438 fps | 99.4% |
| Vihtavuori N530 | <<locked>> | 88% | 56,057 psi | 90% | 2415 fps | 100% |
| Vihtavuori N540 | <<locked>> | 92% | 53,867 psi | 86% | 2388 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 51,445 psi | 82% | 2444 fps | 99.2% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 37,391 psi | 60% | 2293 fps | 97.8% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 53,272 psi | 85% | 2425 fps | 100% |
| Winchester 748 | <<locked>> | 88% | 55,579 psi | 89% | 2457 fps | 100% |
| Winchester 760ᴾ | <<locked>> | 100% | 54,041 psi | 87% | 2500 fps | 98% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 31,270 psi | 50% | 2215 fps | 97.1% |
| Winchester StaBALL Match | <<locked>> | 90% | 54,128 psi | 87% | 2441 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% | 45,034 psi | 72% | 2211 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 48,892 psi | 78% | 2306 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 37,594 psi | 60% | 2149 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 44,063 psi | 71% | 2274 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 45,440 psi | 73% | 2251 fps | 95% |
| Accurate 4064 | <<locked>> | 80% | 35,578 psi | 57% | 2146 fps | 100% |
| Accurate 4350 | <<locked>> | 86% | 31,198 psi | 50% | 2119 fps | 95% |
| ADI AR 2206H | <<locked>> | 80% | 41,220 psi | 66% | 2238 fps | 98.9% |
| ADI AR 2208 | <<locked>> | 80% | 35,143 psi | 56% | 2110 fps | 96.8% |
| ADI Benchmark 8208 | <<locked>> | 80% | 43,221 psi | 69% | 2244 fps | 99.7% |
| Alliant AR-Comp | <<locked>> | 80% | 43,091 psi | 69% | 2234 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 50,343 psi | 81% | 2415 fps | 100% |
| Alliant Power Pro 2000-MR | 48.1 gr | 80% | 37,246 psi | 60% | 2257 fps | 97.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 34,461 psi | 55% | 2129 fps | 98.3% |
| Alliant Reloder-10x | <<locked>> | 80% | 50,720 psi | 81% | 2290 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 37,014 psi | 59% | 2182 fps | 97.6% |
| Alliant Reloder-16 | <<locked>> | 86% | 32,474 psi | 52% | 2136 fps | 95.2% |
| Alliant Reloder-17 | <<locked>> | 80% | 29,646 psi | 48% | 2096 fps | 95.9% |
| Alliant Reloder-23 | <<locked>> | 94% | 29,356 psi | 47% | 2093 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 98% | 35,853 psi | 57% | 2297 fps | 95.6% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 52,214 psi | 84% | 2277 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 40,248 psi | 65% | 2241 fps | 97.8% |
| Bofors RP3 | <<locked>> | 80% | 33,808 psi | 54% | 2133 fps | 98.2% |
| Bofors RP7 | <<locked>> | 92% | 44,991 psi | 72% | 2280 fps | 95.3% |
| Hodgdon Benchmark | <<locked>> | 80% | 45,339 psi | 73% | 2238 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 41,698 psi | 67% | 2264 fps | 99.9% |
| Hodgdon CFE223 | <<locked>> | 80% | 45,759 psi | 73% | 2382 fps | 99.3% |
| Hodgdon H322 | <<locked>> | 80% | 49,487 psi | 79% | 2323 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 50,096 psi | 80% | 2346 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 34,824 psi | 56% | 2133 fps | 95.6% |
| Hodgdon H414 | <<locked>> | 92% | 41,568 psi | 67% | 2306 fps | 95.2% |
| Hodgdon H4350 | <<locked>> | 94% | 48,544 psi | 78% | 2372 fps | 95.4% |
| Hodgdon H4895 | <<locked>> | 80% | 41,524 psi | 67% | 2244 fps | 99.3% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 27,731 psi | 44% | 2001 fps | 95.1% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 37,318 psi | 60% | 2221 fps | 99% |
| Hodgdon Superformance | <<locked>> | 94% | 44,469 psi | 71% | 2372 fps | 95.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,150 psi | 42% | 1280 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 40,001 psi | 64% | 2208 fps | 99% |
| IMR 3031 | <<locked>> | 80% | 40,886 psi | 66% | 2241 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 36,869 psi | 59% | 2139 fps | 97.6% |
| IMR 4166 Enduron | <<locked>> | 82% | 41,916 psi | 67% | 2198 fps | 95.1% |
| IMR 4198 | <<locked>> | 80% | 51,111 psi | 82% | 2254 fps | 100% |
| IMR 4350 | <<locked>> | 96% | 44,976 psi | 72% | 2303 fps | 95.3% |
| IMR 4451 Enduron | <<locked>> | 90% | 44,266 psi | 71% | 2270 fps | 95.6% |
| IMR 4831 | <<locked>> | 88% | 32,532 psi | 52% | 2133 fps | 95.5% |
| IMR 4895 | <<locked>> | 80% | 37,884 psi | 61% | 2208 fps | 98.4% |
| IMR 8208 XBR | <<locked>> | 80% | 43,221 psi | 69% | 2244 fps | 99.7% |
| Lovex D073.5 | <<locked>> | 80% | 48,617 psi | 78% | 2313 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 39,943 psi | 64% | 2221 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 41,698 psi | 67% | 2185 fps | 98.9% |
| Lovex S062 | <<locked>> | 80% | 36,680 psi | 59% | 2142 fps | 99% |
| Lovex S065 | <<locked>> | 86% | 36,230 psi | 58% | 2136 fps | 95% |
| Lovex S070 | <<locked>> | 92% | 40,959 psi | 66% | 2244 fps | 95.2% |
| Norma 201 | <<locked>> | 80% | 40,625 psi | 65% | 2198 fps | 99.5% |
| Norma 202 | <<locked>> | 80% | 40,640 psi | 65% | 2208 fps | 100% |
| Norma 203B | <<locked>> | 80% | 36,405 psi | 58% | 2172 fps | 98% |
| Norma URP | <<locked>> | 86% | 32,111 psi | 51% | 2126 fps | 95% |
| Ramshot Big Game | <<locked>> | 80% | 35,868 psi | 58% | 2185 fps | 97.6% |
| Ramshot Hunter | <<locked>> | 92% | 38,043 psi | 61% | 2247 fps | 95% |
| Ramshot TAC | <<locked>> | 80% | 43,163 psi | 69% | 2251 fps | 97.2% |
| Ramshot Wild Boar | <<locked>> | 80% | 42,322 psi | 68% | 2267 fps | 99% |
| Ramshot X-Terminator | <<locked>> | 80% | 46,760 psi | 75% | 2287 fps | 99.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,455 psi | 42% | 1309 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 48,501 psi | 78% | 2313 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 40,292 psi | 65% | 2211 fps | 95.4% |
| ReloadSwiss RS 52 | 46.6 gr | 80% | 38,450 psi | 62% | 2267 fps | 98% |
| ReloadSwiss RS 60 | 47.3 gr | 80% | 31,546 psi | 51% | 2152 fps | 99% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 33,388 psi | 54% | 2182 fps | 95.3% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 36,332 psi | 58% | 2238 fps | 95.2% |
| Rottweil R 901 | <<locked>> | 80% | 44,440 psi | 71% | 2234 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 38,522 psi | 62% | 2159 fps | 99.3% |
| Rottweil R 903 | <<locked>> | 80% | 31,807 psi | 51% | 2083 fps | 97.4% |
| Rottweil R 907 | <<locked>> | 92% | 44,991 psi | 72% | 2280 fps | 95.3% |
| Shooters World Long Rifle | <<locked>> | 86% | 36,230 psi | 58% | 2136 fps | 95% |
| Shooters World Match Rifle | <<locked>> | 80% | 39,943 psi | 64% | 2221 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 36,680 psi | 59% | 2142 fps | 99% |
| Shooters World SW4350 | <<locked>> | 92% | 40,959 psi | 66% | 2244 fps | 95.2% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 51,314 psi | 82% | 2329 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 32,866 psi | 53% | 2126 fps | 96.8% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 51,547 psi | 83% | 2306 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 41,191 psi | 66% | 2224 fps | 97.3% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 39,740 psi | 64% | 2211 fps | 98.6% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 42,105 psi | 68% | 2159 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 34,780 psi | 56% | 2051 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 92% | 42,859 psi | 69% | 2218 fps | 95.4% |
| Somchem S321 | <<locked>> | 80% | 46,586 psi | 75% | 2313 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 41,640 psi | 67% | 2162 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 41,017 psi | 66% | 2224 fps | 98.8% |
| Somchem S355 | <<locked>> | 80% | 32,982 psi | 53% | 2093 fps | 97.5% |
| Somchem S365 | <<locked>> | 82% | 25,309 psi | 41% | 1988 fps | 95.5% |
| Vihtavuori N130 | <<locked>> | 80% | 47,601 psi | 76% | 2208 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 42,308 psi | 68% | 2156 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 37,797 psi | 61% | 2146 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 38,319 psi | 61% | 2149 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 31,111 psi | 50% | 2037 fps | 98.2% |
| Vihtavuori N160 | <<locked>> | 86% | 33,547 psi | 54% | 2126 fps | 95.5% |
| Vihtavuori N530 | <<locked>> | 80% | 43,207 psi | 69% | 2241 fps | 99.8% |
| Vihtavuori N540 | <<locked>> | 80% | 36,883 psi | 59% | 2146 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 86% | 32,880 psi | 53% | 2129 fps | 95.1% |
| Vihtavuori N555 | <<locked>> | 94% | 31,009 psi | 50% | 2159 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 27,905 psi | 45% | 1975 fps | 95.2% |
| Winchester 748 | <<locked>> | 80% | 42,424 psi | 68% | 2277 fps | 100% |
| Winchester 760 | <<locked>> | 92% | 41,568 psi | 67% | 2306 fps | 95.2% |
| Winchester StaBALL HD | <<locked>> | 98% | 29,341 psi | 47% | 2159 fps | 95.9% |
| Winchester StaBALL Match | <<locked>> | 80% | 39,015 psi | 63% | 2215 fps | 98.9% |
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 105 powders for .338 RCM loaded with the .338 | 250gr | Speer Grand Slam. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 2,562 fps; across all powders the maximum-charge window runs from 1,434 fps to 2,562 fps. Accurate 4350 gives the best case fill at 100 %, and 105 of the 105 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (430 MPa), the top charges use 50–90 %, leaving at least 10 % headroom. The 250.0 gr projectile in 0.338" calls for a 1:6.0 twist; slower twists will usually not stabilise this weight. Accurate 4350, Alliant Reloder-16, Alliant Reloder-23 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 Power Pro 2000-MR, ReloadSwiss RS 52 rank at the top here: for .338 RCM with the .338 | 250gr | Speer Grand Slam 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.