Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 300gr | Woodleigh RN SN bullet and 72 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ReloadSwiss RS 76 and Winchester StaBALL HD.
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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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 90% | 54,911 psi | 86% | 2385 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 55,695 psi | 87% | 2398 fps | 100% |
| Accurate High Country | <<locked>> | 88% | 56,521 psi | 89% | 2523 fps | 100% |
| Accurate MAGPRO | <<locked>> | 90% | 57,406 psi | 90% | 2530 fps | 99.7% |
| ADI AR 2209 | <<locked>> | 88% | 56,492 psi | 89% | 2461 fps | 100% |
| ADI AR 2213 | <<locked>> | 90% | 54,389 psi | 85% | 2474 fps | 99.9% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 56,173 psi | 88% | 2497 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 48,675 psi | 76% | 2484 fps | 97.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 50,531 psi | 79% | 2470 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 56,623 psi | 89% | 2457 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 56,898 psi | 89% | 2444 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 55,985 psi | 88% | 2451 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 90% | 54,723 psi | 86% | 2467 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 56,434 psi | 88% | 2431 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 56,057 psi | 88% | 2493 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 56,855 psi | 89% | 2513 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 53,011 psi | 83% | 2530 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 55,303 psi | 87% | 2441 fps | 98.6% |
| Bofors RP15 | <<locked>> | 94% | 57,624 psi | 90% | 2503 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 55,695 psi | 87% | 2510 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 54,723 psi | 86% | 2467 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 57,217 psi | 90% | 2395 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 54,099 psi | 85% | 2467 fps | 100% |
| Hodgdon H414 | <<locked>> | 82% | 57,101 psi | 89% | 2448 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 57,667 psi | 90% | 2464 fps | 99.8% |
| Hodgdon H4831 SC | <<locked>> | 90% | 56,594 psi | 89% | 2451 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 57,014 psi | 89% | 2375 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 54,926 psi | 86% | 2569 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,463 psi | 59% | 1499 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 55,637 psi | 87% | 2392 fps | 100% |
| IMR 4831 | <<locked>> | 84% | 56,028 psi | 88% | 2392 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 54,882 psi | 86% | 2402 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 92% | 56,463 psi | 88% | 2507 fps | 100% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 46,311 psi | 73% | 2402 fps | 99.5% |
| Lovex S065 | <<locked>> | 82% | 56,057 psi | 88% | 2369 fps | 100% |
| Lovex S070 | <<locked>> | 82% | 54,259 psi | 85% | 2369 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 56,376 psi | 88% | 2402 fps | 100% |
| Norma 204 | <<locked>> | 84% | 56,681 psi | 89% | 2444 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 46,760 psi | 73% | 2421 fps | 100% |
| Norma MRP | <<locked>> | 88% | 54,810 psi | 86% | 2484 fps | 100% |
| Norma URP | <<locked>> | 84% | 57,653 psi | 90% | 2428 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 57,392 psi | 90% | 2526 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 56,492 psi | 89% | 2438 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 55,738 psi | 87% | 2467 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,435 psi | 60% | 1535 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 55,825 psi | 87% | 2421 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 54,099 psi | 85% | 2444 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 55,492 psi | 87% | 2566 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 54,592 psi | 86% | 2536 fps | 99.7% |
| Rottweil R 904 | <<locked>> | 88% | 57,276 psi | 90% | 2431 fps | 100% |
| Rottweil R 905 | <<locked>> | 88% | 55,680 psi | 87% | 2444 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 57,217 psi | 90% | 2395 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 82% | 56,057 psi | 88% | 2369 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 54,259 psi | 85% | 2369 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 54,926 psi | 86% | 2333 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 55,274 psi | 87% | 2441 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 55,042 psi | 86% | 2382 fps | 99.6% |
| Somchem S365 | <<locked>> | 84% | 55,056 psi | 86% | 2385 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 55,970 psi | 88% | 2415 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 55,550 psi | 87% | 2372 fps | 100% |
| Vihtavuori N165 | <<locked>> | 92% | 55,724 psi | 87% | 2402 fps | 100% |
| Vihtavuori N170 | <<locked>> | 96% | 54,375 psi | 85% | 2425 fps | 96.9% |
| Vihtavuori N550 | <<locked>> | 82% | 54,810 psi | 86% | 2382 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 54,969 psi | 86% | 2411 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 54,418 psi | 85% | 2487 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 94% | 54,621 psi | 86% | 2477 fps | 99.8% |
| Vihtavuori N568 | <<locked>> | 98% | 55,448 psi | 87% | 2536 fps | 99.5% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 56,478 psi | 89% | 2589 fps | 98.6% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 54,824 psi | 86% | 2333 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 57,290 psi | 90% | 2448 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 55,376 psi | 87% | 2513 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 55,883 psi | 88% | 2415 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 3100 | <<locked>> | 80% | 39,407 psi | 62% | 2169 fps | 99.9% |
| Accurate 4350 | <<locked>> | 80% | 52,214 psi | 82% | 2356 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 42,801 psi | 67% | 2320 fps | 98.7% |
| Accurate MAGPRO | <<locked>> | 80% | 40,437 psi | 63% | 2270 fps | 97.1% |
| ADI AR 2209 | <<locked>> | 80% | 43,395 psi | 68% | 2274 fps | 99.4% |
| ADI AR 2213 | <<locked>> | 80% | 38,711 psi | 61% | 2221 fps | 97.6% |
| ADI AR 2217 | <<locked>> | 84% | 32,996 psi | 52% | 2106 fps | 95.9% |
| ADI AR 2218 | <<locked>> | 96% | 42,322 psi | 66% | 2365 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 80% | 26,426 psi | 41% | 1988 fps | 95.9% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 43,787 psi | 69% | 2274 fps | 99.4% |
| Alliant Reloder-16 | <<locked>> | 80% | 49,835 psi | 78% | 2356 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 43,410 psi | 68% | 2267 fps | 99.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 39,233 psi | 61% | 2231 fps | 98.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 38,000 psi | 60% | 2182 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 32,895 psi | 52% | 2133 fps | 99.7% |
| Alliant Reloder-26 | <<locked>> | 80% | 42,250 psi | 66% | 2316 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 42,569 psi | 67% | 2362 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 40,596 psi | 64% | 2201 fps | 95% |
| Bofors RP15 | <<locked>> | 80% | 36,608 psi | 57% | 2178 fps | 98.1% |
| Bofors RP30 | <<locked>> | 80% | 30,356 psi | 48% | 2073 fps | 95.2% |
| Bofors RP5 | <<locked>> | 80% | 39,233 psi | 61% | 2231 fps | 98.8% |
| Bofors RP7 | <<locked>> | 80% | 53,824 psi | 84% | 2352 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 31,401 psi | 49% | 2073 fps | 95.9% |
| Hodgdon H414 | <<locked>> | 80% | 53,476 psi | 84% | 2402 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 41,307 psi | 65% | 2224 fps | 97.7% |
| Hodgdon H4831 SC | <<locked>> | 80% | 40,538 psi | 64% | 2211 fps | 97.5% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 47,065 psi | 74% | 2254 fps | 100% |
| Hodgdon Retumbo | 70.8 gr | 80% | 32,155 psi | 50% | 2162 fps | 97.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,152 psi | 44% | 1339 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 49,124 psi | 77% | 2306 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 49,269 psi | 77% | 2306 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 42,714 psi | 67% | 2218 fps | 98.1% |
| IMR 7828 SSC | <<locked>> | 80% | 37,507 psi | 59% | 2208 fps | 97.4% |
| IMR 8133 Enduron | <<locked>> | 88% | 31,009 psi | 49% | 2110 fps | 95.3% |
| Lovex S065 | <<locked>> | 80% | 52,591 psi | 82% | 2326 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 51,068 psi | 80% | 2326 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 33,953 psi | 53% | 2067 fps | 99.3% |
| Norma 204 | <<locked>> | 80% | 49,647 psi | 78% | 2349 fps | 99.8% |
| Norma 217 | <<locked>> | 84% | 27,311 psi | 43% | 2034 fps | 95.9% |
| Norma MRP | <<locked>> | 80% | 41,365 psi | 65% | 2287 fps | 99.8% |
| Norma URP | <<locked>> | 80% | 50,720 psi | 79% | 2339 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 37,144 psi | 58% | 2215 fps | 97.7% |
| Ramshot Hunter | <<locked>> | 80% | 49,632 psi | 78% | 2349 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 33,257 psi | 52% | 2116 fps | 98.1% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,935 psi | 45% | 1375 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 52,098 psi | 82% | 2375 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 50,502 psi | 79% | 2398 fps | 100% |
| ReloadSwiss RS 76 | 75.7 gr | 80% | 31,038 psi | 49% | 2139 fps | 98.3% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 34,925 psi | 55% | 2208 fps | 95.5% |
| Rottweil R 904 | <<locked>> | 80% | 44,512 psi | 70% | 2251 fps | 98.8% |
| Rottweil R 905 | <<locked>> | 80% | 42,801 psi | 67% | 2257 fps | 99.4% |
| Rottweil R 907 | <<locked>> | 80% | 53,824 psi | 84% | 2352 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 52,591 psi | 82% | 2326 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 51,068 psi | 80% | 2326 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 51,459 psi | 81% | 2287 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 42,467 psi | 67% | 2254 fps | 99.3% |
| Somchem S361 | <<locked>> | 80% | 45,252 psi | 71% | 2244 fps | 98.4% |
| Somchem S365 | <<locked>> | 80% | 48,240 psi | 76% | 2303 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 43,265 psi | 68% | 2238 fps | 99.7% |
| Vihtavuori N160 | <<locked>> | 80% | 52,214 psi | 82% | 2333 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 37,768 psi | 59% | 2139 fps | 98.8% |
| Vihtavuori N170 | <<locked>> | 92% | 47,558 psi | 75% | 2323 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 51,401 psi | 81% | 2339 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 42,482 psi | 67% | 2244 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 41,278 psi | 65% | 2283 fps | 97.9% |
| Vihtavuori N565 | <<locked>> | 80% | 34,171 psi | 54% | 2136 fps | 95.9% |
| Vihtavuori N568 | <<locked>> | 86% | 36,289 psi | 57% | 2221 fps | 95.3% |
| Vihtavuori N570 | <<locked>> | 92% | 42,453 psi | 67% | 2369 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 51,184 psi | 80% | 2293 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 53,679 psi | 84% | 2405 fps | 100% |
| Winchester StaBALL HD | 72.7 gr | 80% | 35,099 psi | 55% | 2231 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 39,740 psi | 62% | 2182 fps | 98.8% |
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 72 powders for .338 Rem. Ultra Mag. loaded with the .338 | 300gr | Woodleigh RN SN. Vihtavuori N570 delivers the highest muzzle velocity at 2,589 fps; across all powders the maximum-charge window runs from 1,499 fps to 2,589 fps. ADI AR 2217 gives the best case fill at 100 %, and 72 of the 72 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.338" calls for a 1:15.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2218, ADI AR 2225 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. Hodgdon Retumbo, ReloadSwiss RS 76, Winchester StaBALL HD rank at the top here: for .338 Rem. Ultra Mag. with the .338 | 300gr | Woodleigh RN SN 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.