Load Specifications
Bullet Manufacturer:Sierra
Bullet Weight:250 gr
Bullet Diameter:0.338"
Bullet Length:<<locked>>
Caliber:.338 Weatherby RPM load data
Case Length (l3):2.55"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:81.6 Grains of Water
Primer Size:Large Rifle Magnum (LRM)
Barrel Length:24"
Max. allowed Pressure:65,000 psi
Recommended Twist Rate:1:12.5
Load data in caliber .338 Weatherby RPM with .338 | 250gr | Sierra MatchKing bullet and 107 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 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: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 86% | 56,608 psi | 87% | 2379 fps | 100% |
| Accurate 2460 | <<locked>> | 84% | 58,465 psi | 90% | 2448 fps | 100% |
| Accurate 2495 | <<locked>> | 92% | 58,334 psi | 90% | 2441 fps | 100% |
| Accurate 2520 | <<locked>> | 86% | 56,768 psi | 87% | 2464 fps | 100% |
| Accurate 2700 | <<locked>> | 92% | 57,914 psi | 89% | 2454 fps | 97.9% |
| Accurate 4064 | <<locked>> | 94% | 58,146 psi | 89% | 2484 fps | 100% |
| Accurate 4350ᴾ | <<locked>> | 100% | 53,940 psi | 83% | 2523 fps | 99.8% |
| Accurate LT-30 | <<locked>> | 82% | 58,537 psi | 90% | 2359 fps | 100% |
| ADI AR 2206H | <<locked>> | 88% | 55,419 psi | 85% | 2474 fps | 100% |
| ADI AR 2208 | <<locked>> | 94% | 56,188 psi | 86% | 2470 fps | 100% |
| ADI Benchmark 8208 | <<locked>> | 88% | 58,015 psi | 89% | 2474 fps | 100% |
| Alliant AR-Comp | <<locked>> | 86% | 55,114 psi | 85% | 2402 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 82% | 56,463 psi | 87% | 2520 fps | 100% |
| Alliant Power Pro 2000-MR | <<locked>> | 92% | 58,726 psi | 90% | 2631 fps | 100% |
| Alliant Reloder- TS 15.5 | <<locked>> | 94% | 56,173 psi | 86% | 2493 fps | 100% |
| Alliant Reloder-10x | <<locked>> | 82% | 56,028 psi | 86% | 2375 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 92% | 56,869 psi | 87% | 2513 fps | 100% |
| Alliant Reloder-16ᴾ | <<locked>> | 100% | 52,025 psi | 80% | 2523 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 98% | 56,579 psi | 87% | 2602 fps | 100% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 37,115 psi | 57% | 2300 fps | 98.8% |
| Alliant Reloder-26ᴾ | <<locked>> | 100% | 41,046 psi | 63% | 2434 fps | 97.9% |
| Baschieri & Pellagri 106 | <<locked>> | 82% | 57,696 psi | 89% | 2362 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 88% | 55,071 psi | 85% | 2490 fps | 99.9% |
| Bofors RP3 | <<locked>> | 94% | 56,710 psi | 87% | 2507 fps | 100% |
| Bofors RP7 | <<locked>> | 98% | 56,942 psi | 88% | 2480 fps | 98% |
| Hodgdon Benchmark | <<locked>> | 86% | 56,333 psi | 87% | 2411 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 88% | 57,203 psi | 88% | 2503 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 84% | 55,463 psi | 85% | 2546 fps | 100% |
| Hodgdon H322 | <<locked>> | 82% | 55,361 psi | 85% | 2421 fps | 100% |
| Hodgdon H335 | <<locked>> | 82% | 56,260 psi | 87% | 2444 fps | 100% |
| Hodgdon H380 | <<locked>> | 94% | 57,870 psi | 89% | 2520 fps | 99.8% |
| Hodgdon H414ᴾ | <<locked>> | 100% | 56,840 psi | 87% | 2566 fps | 98.7% |
| Hodgdon H4350 | <<locked>> | 98% | 57,914 psi | 89% | 2530 fps | 97.6% |
| Hodgdon H4895 | <<locked>> | 88% | 55,970 psi | 86% | 2484 fps | 100% |
| Hodgdon Hybrid 100Vᴾ | <<locked>> | 100% | 48,138 psi | 74% | 2415 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 92% | 58,668 psi | 90% | 2556 fps | 100% |
| Hodgdon Superformanceᴾ | <<locked>> | 100% | 58,175 psi | 89% | 2608 fps | 98.5% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 35,302 psi | 54% | 1460 fps | 100% |
| Hodgdon VARGET | <<locked>> | 90% | 57,159 psi | 88% | 2484 fps | 100% |
| IMR 3031 | <<locked>> | 88% | 55,767 psi | 86% | 2461 fps | 100% |
| IMR 4064 | <<locked>> | 92% | 55,941 psi | 86% | 2457 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 90% | 55,999 psi | 86% | 2441 fps | 98.3% |
| IMR 4198 | <<locked>> | 82% | 56,362 psi | 87% | 2339 fps | 100% |
| IMR 4350ᴾ | <<locked>> | 100% | 53,330 psi | 82% | 2457 fps | 97.5% |
| IMR 4451 Enduron | <<locked>> | 96% | 55,463 psi | 85% | 2464 fps | 98.2% |
| IMR 4831ᴾ | <<locked>> | 100% | 51,010 psi | 78% | 2467 fps | 99.6% |
| IMR 4895 | <<locked>> | 92% | 58,305 psi | 90% | 2539 fps | 100% |
| IMR 8208 XBR | <<locked>> | 88% | 58,015 psi | 89% | 2474 fps | 100% |
| Lovex D073.5 | <<locked>> | 84% | 58,581 psi | 90% | 2461 fps | 100% |
| Lovex D073.6 | <<locked>> | 90% | 58,610 psi | 90% | 2493 fps | 100% |
| Lovex S060 | <<locked>> | 90% | 58,421 psi | 90% | 2448 fps | 100% |
| Lovex S062 | <<locked>> | 92% | 55,593 psi | 86% | 2451 fps | 100% |
| Lovex S065ᴾ | <<locked>> | 100% | 58,015 psi | 89% | 2503 fps | 99.4% |
| Lovex S070ᴾ | <<locked>> | 100% | 55,230 psi | 85% | 2487 fps | 98.5% |
| Norma 201 | <<locked>> | 90% | 57,522 psi | 88% | 2464 fps | 100% |
| Norma 202 | <<locked>> | 90% | 58,117 psi | 89% | 2464 fps | 100% |
| Norma 203B | <<locked>> | 92% | 56,028 psi | 86% | 2500 fps | 100% |
| Norma 204ᴾ | <<locked>> | 100% | 53,911 psi | 83% | 2500 fps | 96.3% |
| Norma URPᴾ | <<locked>> | 100% | 52,939 psi | 81% | 2507 fps | 99.7% |
| Ramshot Big Game | <<locked>> | 92% | 56,536 psi | 87% | 2526 fps | 100% |
| Ramshot Hunterᴾ | <<locked>> | 100% | 51,764 psi | 80% | 2507 fps | 98.6% |
| Ramshot TAC | <<locked>> | 88% | 58,349 psi | 90% | 2497 fps | 99.6% |
| Ramshot Wild Boar | <<locked>> | 88% | 57,856 psi | 89% | 2510 fps | 100% |
| Ramshot X-Terminator | <<locked>> | 84% | 55,463 psi | 85% | 2434 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 35,781 psi | 55% | 1496 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 84% | 57,609 psi | 89% | 2454 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 94% | 58,073 psi | 89% | 2503 fps | 99.1% |
| ReloadSwiss RS 52 | <<locked>> | 90% | 57,174 psi | 88% | 2572 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 96% | 56,579 psi | 87% | 2602 fps | 100% |
| ReloadSwiss RS 62ᴾ | <<locked>> | 100% | 53,214 psi | 82% | 2539 fps | 99.6% |
| ReloadSwiss RS 70ᴾ | <<locked>> | 100% | 53,519 psi | 82% | 2566 fps | 99.5% |
| Rottweil R 901 | <<locked>> | 88% | 58,740 psi | 90% | 2444 fps | 100% |
| Rottweil R 902 | <<locked>> | 92% | 58,001 psi | 89% | 2464 fps | 100% |
| Rottweil R 903 | <<locked>> | 96% | 56,565 psi | 87% | 2500 fps | 100% |
| Rottweil R 907 | <<locked>> | 98% | 56,942 psi | 88% | 2480 fps | 98% |
| Shooters World Long Rifleᴾ | <<locked>> | 100% | 58,015 psi | 89% | 2503 fps | 99.4% |
| Shooters World Match Rifle | <<locked>> | 90% | 58,610 psi | 90% | 2493 fps | 100% |
| Shooters World Precision | <<locked>> | 92% | 55,593 psi | 86% | 2451 fps | 100% |
| Shooters World SW4350ᴾ | <<locked>> | 100% | 55,230 psi | 85% | 2487 fps | 98.5% |
| Shooters World Tactical Rifle | <<locked>> | 82% | 57,232 psi | 88% | 2431 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 96% | 58,421 psi | 90% | 2556 fps | 100% |
| SNPE Vectan SP 3 | <<locked>> | 82% | 56,985 psi | 88% | 2395 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 88% | 56,695 psi | 87% | 2477 fps | 99.7% |
| SNPE Vectan SP 9 | <<locked>> | 90% | 57,087 psi | 88% | 2493 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 88% | 55,854 psi | 86% | 2365 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 94% | 55,753 psi | 86% | 2365 fps | 100% |
| SNPE Vectan Tubal 7000ᴾ | <<locked>> | 100% | 58,711 psi | 90% | 2464 fps | 98.6% |
| Somchem S321 | <<locked>> | 84% | 55,608 psi | 86% | 2461 fps | 100% |
| Somchem S335 | <<locked>> | 90% | 58,450 psi | 90% | 2405 fps | 100% |
| Somchem S341 | <<locked>> | 88% | 56,231 psi | 87% | 2467 fps | 100% |
| Somchem S355 | <<locked>> | 96% | 56,695 psi | 87% | 2493 fps | 100% |
| Somchem S365ᴾ | <<locked>> | 100% | 47,297 psi | 73% | 2464 fps | 100% |
| Vihtavuori N130 | <<locked>> | 84% | 55,840 psi | 86% | 2333 fps | 100% |
| Vihtavuori N133 | <<locked>> | 88% | 56,014 psi | 86% | 2352 fps | 100% |
| Vihtavuori N135 | <<locked>> | 92% | 57,682 psi | 89% | 2425 fps | 100% |
| Vihtavuori N140 | <<locked>> | 92% | 58,668 psi | 90% | 2444 fps | 100% |
| Vihtavuori N150 | <<locked>> | 98% | 58,305 psi | 90% | 2474 fps | 100% |
| Vihtavuori N160ᴾ | <<locked>> | 100% | 55,753 psi | 86% | 2507 fps | 99.8% |
| Vihtavuori N530 | <<locked>> | 88% | 58,755 psi | 90% | 2474 fps | 100% |
| Vihtavuori N540 | <<locked>> | 92% | 56,710 psi | 87% | 2448 fps | 100% |
| Vihtavuori N550ᴾ | <<locked>> | 100% | 54,694 psi | 84% | 2513 fps | 99.7% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 40,074 psi | 62% | 2362 fps | 98.7% |
| Winchester 6.5 StaBALLᴾ | <<locked>> | 100% | 56,173 psi | 86% | 2490 fps | 100% |
| Winchester 748 | <<locked>> | 88% | 58,581 psi | 90% | 2516 fps | 100% |
| Winchester 760ᴾ | <<locked>> | 100% | 57,145 psi | 88% | 2569 fps | 98.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 33,025 psi | 51% | 2293 fps | 98.5% |
| Winchester StaBALL Match | <<locked>> | 90% | 57,072 psi | 88% | 2500 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% | 46,949 psi | 72% | 2260 fps | 100% |
| Accurate 2460 | <<locked>> | 80% | 51,300 psi | 79% | 2362 fps | 100% |
| Accurate 2495 | <<locked>> | 80% | 39,726 psi | 61% | 2201 fps | 100% |
| Accurate 2520 | <<locked>> | 80% | 46,325 psi | 71% | 2329 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 44,715 psi | 69% | 2267 fps | 95.3% |
| Accurate 4064 | <<locked>> | 80% | 37,550 psi | 58% | 2198 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 31,154 psi | 48% | 2136 fps | 95.3% |
| Accurate LT-30 | <<locked>> | 80% | 55,259 psi | 85% | 2323 fps | 100% |
| ADI AR 2206H | <<locked>> | 80% | 43,207 psi | 66% | 2293 fps | 99.4% |
| ADI AR 2208 | <<locked>> | 80% | 36,796 psi | 57% | 2169 fps | 97.6% |
| ADI Benchmark 8208 | <<locked>> | 80% | 45,252 psi | 70% | 2300 fps | 99.9% |
| Alliant AR-Comp | <<locked>> | 80% | 45,513 psi | 70% | 2287 fps | 100% |
| Alliant Power Pro 1200-R | <<locked>> | 80% | 52,881 psi | 81% | 2474 fps | 100% |
| Alliant Power Pro 2000-MR | 50.9 gr | 80% | 39,044 psi | 60% | 2323 fps | 98.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 36,260 psi | 56% | 2188 fps | 98.9% |
| Alliant Reloder-10x | <<locked>> | 80% | 52,837 psi | 81% | 2339 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 38,986 psi | 60% | 2241 fps | 98.3% |
| Alliant Reloder-16 | <<locked>> | 84% | 32,039 psi | 49% | 2149 fps | 95.5% |
| Alliant Reloder-17 | 50.2 gr | 80% | 31,343 psi | 48% | 2162 fps | 97.1% |
| Alliant Reloder-23 | <<locked>> | 90% | 27,441 psi | 42% | 2067 fps | 95% |
| Alliant Reloder-26 | <<locked>> | 94% | 33,417 psi | 51% | 2267 fps | 95.1% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 54,418 psi | 84% | 2326 fps | 100% |
| Baschieri & Pellagri 107 | <<locked>> | 80% | 42,351 psi | 65% | 2303 fps | 98.5% |
| Bofors RP3 | <<locked>> | 80% | 35,752 psi | 55% | 2192 fps | 98.9% |
| Bofors RP7 | <<locked>> | 90% | 44,541 psi | 69% | 2300 fps | 95.6% |
| Hodgdon Benchmark | <<locked>> | 80% | 47,137 psi | 73% | 2290 fps | 100% |
| Hodgdon BL-C2 | <<locked>> | 80% | 43,787 psi | 67% | 2320 fps | 100% |
| Hodgdon CFE223 | <<locked>> | 80% | 48,269 psi | 74% | 2444 fps | 99.7% |
| Hodgdon H322 | <<locked>> | 80% | 51,895 psi | 80% | 2379 fps | 100% |
| Hodgdon H335 | <<locked>> | 80% | 52,620 psi | 81% | 2402 fps | 100% |
| Hodgdon H380 | <<locked>> | 80% | 36,811 psi | 57% | 2195 fps | 96.6% |
| Hodgdon H414 | <<locked>> | 90% | 41,118 psi | 63% | 2326 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 90% | 45,107 psi | 69% | 2346 fps | 95% |
| Hodgdon H4895 | <<locked>> | 80% | 43,584 psi | 67% | 2303 fps | 99.7% |
| Hodgdon Hybrid 100V | <<locked>> | 82% | 27,499 psi | 42% | 2018 fps | 95.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 39,363 psi | 61% | 2280 fps | 99.5% |
| Hodgdon Superformance | <<locked>> | 92% | 43,874 psi | 67% | 2392 fps | 95.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 26,339 psi | 41% | 1302 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 41,959 psi | 65% | 2264 fps | 99.5% |
| IMR 3031 | <<locked>> | 80% | 43,178 psi | 66% | 2297 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 38,624 psi | 59% | 2195 fps | 98.3% |
| IMR 4166 Enduron | <<locked>> | 80% | 41,176 psi | 63% | 2215 fps | 95.3% |
| IMR 4198 | <<locked>> | 80% | 53,113 psi | 82% | 2300 fps | 100% |
| IMR 4350 | <<locked>> | 94% | 44,483 psi | 68% | 2323 fps | 95.6% |
| IMR 4451 Enduron | <<locked>> | 86% | 41,017 psi | 63% | 2241 fps | 95.2% |
| IMR 4831 | <<locked>> | 84% | 30,443 psi | 47% | 2103 fps | 95% |
| IMR 4895 | <<locked>> | 80% | 39,929 psi | 61% | 2267 fps | 99% |
| IMR 8208 XBR | <<locked>> | 80% | 45,252 psi | 70% | 2300 fps | 99.9% |
| Lovex D073.5 | <<locked>> | 80% | 51,126 psi | 79% | 2372 fps | 100% |
| Lovex D073.6 | <<locked>> | 80% | 42,250 psi | 65% | 2277 fps | 100% |
| Lovex S060 | <<locked>> | 80% | 43,410 psi | 67% | 2238 fps | 99.4% |
| Lovex S062 | <<locked>> | 80% | 38,493 psi | 59% | 2198 fps | 99.5% |
| Lovex S065 | <<locked>> | 84% | 35,737 psi | 55% | 2149 fps | 95.2% |
| Lovex S070 | <<locked>> | 90% | 40,669 psi | 63% | 2264 fps | 95.5% |
| Norma 201 | <<locked>> | 80% | 42,453 psi | 65% | 2254 fps | 99.8% |
| Norma 202 | <<locked>> | 80% | 42,540 psi | 65% | 2257 fps | 100% |
| Norma 203B | <<locked>> | 80% | 38,377 psi | 59% | 2231 fps | 98.6% |
| Norma 204 | <<locked>> | 98% | 50,531 psi | 78% | 2454 fps | 95.6% |
| Norma URP | <<locked>> | 84% | 31,908 psi | 49% | 2142 fps | 95.3% |
| Ramshot Big Game | <<locked>> | 80% | 37,710 psi | 58% | 2241 fps | 98.4% |
| Ramshot Hunter | <<locked>> | 90% | 37,608 psi | 58% | 2267 fps | 95.3% |
| Ramshot TAC | <<locked>> | 80% | 45,179 psi | 70% | 2310 fps | 97.9% |
| Ramshot Wild Boar | <<locked>> | 80% | 44,527 psi | 69% | 2326 fps | 99.5% |
| Ramshot X-Terminator | <<locked>> | 80% | 48,718 psi | 75% | 2343 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 26,643 psi | 41% | 1335 fps | 100% |
| ReloadSwiss RS 40 | <<locked>> | 80% | 50,865 psi | 78% | 2369 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 39,711 psi | 61% | 2228 fps | 95.7% |
| ReloadSwiss RS 52 | <<locked>> | 80% | 40,814 psi | 63% | 2329 fps | 98.7% |
| ReloadSwiss RS 60 | 50.2 gr | 80% | 33,359 psi | 51% | 2221 fps | 99.6% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 33,257 psi | 51% | 2201 fps | 95.6% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 35,824 psi | 55% | 2254 fps | 95.5% |
| Rottweil R 901 | <<locked>> | 80% | 46,311 psi | 71% | 2283 fps | 100% |
| Rottweil R 902 | <<locked>> | 80% | 40,379 psi | 62% | 2215 fps | 99.6% |
| Rottweil R 903 | <<locked>> | 80% | 33,750 psi | 52% | 2142 fps | 98.2% |
| Rottweil R 907 | <<locked>> | 90% | 44,541 psi | 69% | 2300 fps | 95.6% |
| Shooters World Long Rifle | <<locked>> | 84% | 35,737 psi | 55% | 2149 fps | 95.2% |
| Shooters World Match Rifle | <<locked>> | 80% | 42,250 psi | 65% | 2277 fps | 100% |
| Shooters World Precision | <<locked>> | 80% | 38,493 psi | 59% | 2198 fps | 99.5% |
| Shooters World SW4350 | <<locked>> | 90% | 40,669 psi | 63% | 2264 fps | 95.5% |
| Shooters World Tactical Rifle | <<locked>> | 80% | 53,432 psi | 82% | 2385 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 34,679 psi | 53% | 2188 fps | 97.7% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 53,664 psi | 83% | 2356 fps | 100% |
| SNPE Vectan SP 7 | <<locked>> | 80% | 43,337 psi | 67% | 2287 fps | 98% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 41,742 psi | 64% | 2270 fps | 99.1% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 43,816 psi | 67% | 2208 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 36,361 psi | 56% | 2100 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 39,682 psi | 61% | 2192 fps | 95% |
| Somchem S321 | <<locked>> | 80% | 48,921 psi | 75% | 2372 fps | 100% |
| Somchem S335 | <<locked>> | 80% | 43,439 psi | 67% | 2215 fps | 100% |
| Somchem S341 | <<locked>> | 80% | 43,120 psi | 66% | 2283 fps | 99.3% |
| Somchem S355 | <<locked>> | 80% | 34,708 psi | 53% | 2149 fps | 98.2% |
| Somchem S365 | <<locked>> | 80% | 25,164 psi | 39% | 2008 fps | 95.9% |
| Vihtavuori N130 | <<locked>> | 80% | 49,487 psi | 76% | 2257 fps | 100% |
| Vihtavuori N133 | <<locked>> | 80% | 44,121 psi | 68% | 2201 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 39,711 psi | 61% | 2195 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 40,350 psi | 62% | 2205 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 32,895 psi | 51% | 2096 fps | 98.8% |
| Vihtavuori N160 | <<locked>> | 84% | 33,228 psi | 51% | 2142 fps | 95.7% |
| Vihtavuori N530 | <<locked>> | 80% | 45,237 psi | 70% | 2297 fps | 100% |
| Vihtavuori N540 | <<locked>> | 80% | 38,885 psi | 60% | 2198 fps | 100% |
| Vihtavuori N550 | <<locked>> | 84% | 32,634 psi | 50% | 2146 fps | 95.3% |
| Vihtavuori N555 | <<locked>> | 90% | 29,124 psi | 45% | 2129 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 29,254 psi | 45% | 2034 fps | 96.3% |
| Winchester 748 | <<locked>> | 80% | 44,904 psi | 69% | 2339 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 41,307 psi | 64% | 2329 fps | 95.6% |
| Winchester StaBALL HD | <<locked>> | 94% | 27,398 psi | 42% | 2129 fps | 95.2% |
| Winchester StaBALL Match | <<locked>> | 80% | 41,046 psi | 63% | 2274 fps | 99.4% |
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 .338 Weatherby RPM loaded with the .338 | 250gr | Sierra MatchKing. Alliant Power Pro 2000-MR delivers the highest muzzle velocity at 2,631 fps; across all powders the maximum-charge window runs from 1,460 fps to 2,631 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 (448 MPa), the top charges use 51–90 %, leaving at least 10 % headroom. The 250.0 gr projectile in 0.338" calls for a 1:12.5 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, Alliant Reloder-17 rank at the top here: for .338 Weatherby RPM with the .338 | 250gr | Sierra MatchKing 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.