Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 275gr | Speer SSP bullet and 73 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>> | 92% | 55,405 psi | 87% | 2497 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 56,434 psi | 88% | 2513 fps | 100% |
| Accurate MAGPRO | <<locked>> | 90% | 54,012 psi | 85% | 2589 fps | 99% |
| ADI AR 2209 | <<locked>> | 90% | 57,290 psi | 90% | 2575 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 55,056 psi | 86% | 2585 fps | 99.7% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 53,055 psi | 83% | 2556 fps | 99.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 47,471 psi | 74% | 2523 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 57,406 psi | 90% | 2562 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 56,695 psi | 89% | 2566 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 55,317 psi | 87% | 2582 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 56,797 psi | 89% | 2546 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 56,217 psi | 88% | 2605 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 57,232 psi | 90% | 2631 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 49,429 psi | 77% | 2572 fps | 96.7% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 56,260 psi | 88% | 2549 fps | 98% |
| Bofors RP15 | <<locked>> | 94% | 54,520 psi | 85% | 2569 fps | 99.9% |
| Bofors RP30ᴾ | <<locked>> | 100% | 55,767 psi | 87% | 2615 fps | 99.9% |
| Bofors RP5 | <<locked>> | 92% | 55,317 psi | 87% | 2582 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 54,766 psi | 86% | 2467 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 54,534 psi | 85% | 2575 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 82% | 54,404 psi | 85% | 2520 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 56,826 psi | 89% | 2530 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 54,795 psi | 86% | 2530 fps | 99.2% |
| Hodgdon H4831 SC | <<locked>> | 92% | 57,493 psi | 90% | 2562 fps | 99.5% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 54,041 psi | 85% | 2448 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 54,984 psi | 86% | 2680 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 54,578 psi | 86% | 2552 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,347 psi | 59% | 1568 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 56,507 psi | 89% | 2507 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 56,159 psi | 88% | 2487 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 56,710 psi | 89% | 2507 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 55,782 psi | 87% | 2513 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 94% | 56,811 psi | 89% | 2618 fps | 99.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 43,076 psi | 68% | 2448 fps | 98.4% |
| Lovex S065 | <<locked>> | 84% | 56,927 psi | 89% | 2484 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 55,172 psi | 86% | 2487 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 56,681 psi | 89% | 2510 fps | 100% |
| Norma 204 | <<locked>> | 86% | 57,551 psi | 90% | 2559 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 43,366 psi | 68% | 2470 fps | 99.8% |
| Norma MRP | <<locked>> | 90% | 55,187 psi | 86% | 2598 fps | 100% |
| Norma URP | <<locked>> | 84% | 54,766 psi | 86% | 2500 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 53,911 psi | 84% | 2585 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 86% | 57,217 psi | 90% | 2552 fps | 100% |
| Ramshot Magnum | <<locked>> | 96% | 56,144 psi | 88% | 2575 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,247 psi | 60% | 1608 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 56,478 psi | 89% | 2536 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 54,766 psi | 86% | 2562 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 55,680 psi | 87% | 2674 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 54,781 psi | 86% | 2641 fps | 99.3% |
| Rottweil R 904 | <<locked>> | 88% | 54,621 psi | 86% | 2500 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 90% | 56,362 psi | 88% | 2556 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 54,766 psi | 86% | 2467 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 56,927 psi | 89% | 2484 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 55,172 psi | 86% | 2487 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 56,028 psi | 88% | 2448 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 55,941 psi | 88% | 2552 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 55,941 psi | 88% | 2493 fps | 99.3% |
| Somchem S365 | <<locked>> | 86% | 55,564 psi | 87% | 2500 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 56,826 psi | 89% | 2530 fps | 100% |
| Vihtavuori N150 | <<locked>> | 82% | 57,087 psi | 89% | 2428 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 56,391 psi | 88% | 2490 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 56,449 psi | 88% | 2513 fps | 100% |
| Vihtavuori N170 | <<locked>> | 98% | 55,158 psi | 86% | 2526 fps | 96.1% |
| Vihtavuori N550 | <<locked>> | 84% | 55,695 psi | 87% | 2500 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 55,230 psi | 87% | 2526 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 54,926 psi | 86% | 2598 fps | 99.4% |
| Vihtavuori N565 | <<locked>> | 96% | 55,042 psi | 86% | 2585 fps | 99.6% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 55,695 psi | 87% | 2641 fps | 99% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 52,562 psi | 82% | 2635 fps | 97.1% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 55,941 psi | 88% | 2451 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 54,404 psi | 85% | 2520 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 55,143 psi | 86% | 2625 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 56,724 psi | 89% | 2530 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% | 37,130 psi | 58% | 2221 fps | 99.3% |
| Accurate 4350 | <<locked>> | 80% | 49,443 psi | 77% | 2425 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 37,985 psi | 60% | 2316 fps | 95.2% |
| ADI AR 2209 | <<locked>> | 80% | 41,104 psi | 64% | 2329 fps | 98.4% |
| ADI AR 2213 | <<locked>> | 80% | 36,593 psi | 57% | 2270 fps | 95.9% |
| ADI AR 2217 | <<locked>> | 88% | 35,592 psi | 56% | 2247 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 84% | 28,297 psi | 44% | 2116 fps | 95.7% |
| Alliant Reloder-16 | <<locked>> | 80% | 47,253 psi | 74% | 2428 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 41,162 psi | 65% | 2326 fps | 98.4% |
| Alliant Reloder-22 | <<locked>> | 80% | 36,898 psi | 58% | 2280 fps | 97.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 35,694 psi | 56% | 2241 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 30,980 psi | 49% | 2175 fps | 98.6% |
| Alliant Reloder-26 | <<locked>> | 80% | 39,392 psi | 62% | 2372 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 46,021 psi | 72% | 2516 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 44,034 psi | 69% | 2352 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 34,432 psi | 54% | 2224 fps | 96.5% |
| Bofors RP30 | <<locked>> | 84% | 32,430 psi | 51% | 2211 fps | 95% |
| Bofors RP5 | <<locked>> | 80% | 36,898 psi | 58% | 2280 fps | 97.5% |
| Bofors RP7 | <<locked>> | 80% | 51,576 psi | 81% | 2425 fps | 100% |
| Hodgdon H1000 | <<locked>> | 84% | 33,910 psi | 53% | 2215 fps | 95.8% |
| Hodgdon H414 | <<locked>> | 80% | 50,792 psi | 80% | 2470 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 53,127 psi | 83% | 2480 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 80% | 39,102 psi | 61% | 2274 fps | 96.1% |
| Hodgdon H4831 SC | <<locked>> | 80% | 38,377 psi | 60% | 2260 fps | 95.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 44,512 psi | 70% | 2323 fps | 100% |
| Hodgdon Retumbo | 71.9 gr | 80% | 30,240 psi | 47% | 2195 fps | 95.3% |
| Hodgdon Superformance | <<locked>> | 80% | 50,691 psi | 79% | 2497 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,021 psi | 44% | 1401 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 46,876 psi | 73% | 2369 fps | 99.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 52,736 psi | 83% | 2441 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 46,789 psi | 73% | 2375 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 40,741 psi | 64% | 2274 fps | 96.7% |
| IMR 7828 SSC | <<locked>> | 80% | 35,389 psi | 55% | 2254 fps | 95.5% |
| IMR 8133 Enduron | <<locked>> | 92% | 33,054 psi | 52% | 2244 fps | 95% |
| Lovex S065 | <<locked>> | 80% | 50,357 psi | 79% | 2398 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 48,776 psi | 76% | 2395 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 32,039 psi | 50% | 2116 fps | 98.2% |
| Norma 204 | <<locked>> | 80% | 47,108 psi | 74% | 2408 fps | 99.2% |
| Norma 217 | <<locked>> | 88% | 28,993 psi | 45% | 2162 fps | 95.6% |
| Norma MRP | <<locked>> | 80% | 38,856 psi | 61% | 2343 fps | 99.1% |
| Norma URP | <<locked>> | 80% | 48,211 psi | 76% | 2411 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 34,969 psi | 55% | 2257 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 47,036 psi | 74% | 2415 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 31,096 psi | 49% | 2156 fps | 96.3% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,616 psi | 45% | 1434 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 49,371 psi | 77% | 2444 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 47,471 psi | 74% | 2464 fps | 100% |
| ReloadSwiss RS 76 | 76.9 gr | 80% | 29,167 psi | 46% | 2169 fps | 96.1% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 37,579 psi | 59% | 2352 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 42,366 psi | 66% | 2310 fps | 97.7% |
| Rottweil R 905 | <<locked>> | 80% | 40,495 psi | 63% | 2313 fps | 98.4% |
| Rottweil R 907 | <<locked>> | 80% | 51,576 psi | 81% | 2425 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 50,357 psi | 79% | 2398 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 48,776 psi | 76% | 2395 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 49,226 psi | 77% | 2356 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 40,161 psi | 63% | 2310 fps | 98.3% |
| Somchem S361 | <<locked>> | 80% | 42,975 psi | 67% | 2297 fps | 97.1% |
| Somchem S365 | <<locked>> | 80% | 45,498 psi | 71% | 2372 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 40,973 psi | 64% | 2293 fps | 99% |
| Vihtavuori N150 | <<locked>> | 80% | 53,505 psi | 84% | 2388 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 49,676 psi | 78% | 2402 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 35,694 psi | 56% | 2188 fps | 97.6% |
| Vihtavuori N170 | <<locked>> | 96% | 51,488 psi | 81% | 2474 fps | 95.2% |
| Vihtavuori N550 | <<locked>> | 80% | 48,892 psi | 77% | 2408 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 40,059 psi | 63% | 2306 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 38,899 psi | 61% | 2333 fps | 96.3% |
| Vihtavuori N565 | <<locked>> | 84% | 36,680 psi | 57% | 2280 fps | 95.8% |
| Vihtavuori N568 | <<locked>> | 90% | 39,030 psi | 61% | 2369 fps | 95.2% |
| Vihtavuori N570 | <<locked>> | 96% | 45,687 psi | 72% | 2520 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 48,689 psi | 76% | 2365 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 50,995 psi | 80% | 2470 fps | 100% |
| Winchester StaBALL HD | 73.8 gr | 80% | 32,126 psi | 50% | 2277 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 37,550 psi | 59% | 2231 fps | 97.5% |
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 78 powders for .338 Rem. Ultra Mag. loaded with the .338 | 275gr | Speer SSP. Hodgdon Retumbo delivers the highest muzzle velocity at 2,680 fps; across all powders the maximum-charge window runs from 1,568 fps to 2,680 fps. ADI AR 2217 gives the best case fill at 100 %, and 78 of the 78 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 275.0 gr projectile in 0.338" calls for a 1:16.0 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 | 275gr | Speer SSP they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-50, IMR 7977 Enduron, Lovex D100 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.