Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 300gr | MAKER Expanding Subsonic bullet and 74 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 Alliant Reloder-26.
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 3100 | <<locked>> | 94% | 57,348 psi | 90% | 2395 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 55,042 psi | 86% | 2372 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 55,941 psi | 88% | 2493 fps | 99.4% |
| ADI AR 2209 | <<locked>> | 90% | 55,738 psi | 87% | 2431 fps | 100% |
| ADI AR 2213 | <<locked>> | 94% | 57,029 psi | 89% | 2487 fps | 99.9% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 51,213 psi | 80% | 2408 fps | 99.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 45,745 psi | 72% | 2382 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 55,999 psi | 88% | 2418 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 56,927 psi | 89% | 2425 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 55,274 psi | 87% | 2421 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 94% | 57,116 psi | 90% | 2480 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 54,795 psi | 86% | 2402 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 57,725 psi | 90% | 2500 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 55,027 psi | 86% | 2480 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 47,427 psi | 74% | 2428 fps | 96.6% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 55,027 psi | 86% | 2411 fps | 98% |
| Bofors RP15 | <<locked>> | 96% | 56,275 psi | 88% | 2470 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 53,838 psi | 84% | 2470 fps | 99.9% |
| Bofors RP5 | <<locked>> | 94% | 57,116 psi | 90% | 2480 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 57,014 psi | 89% | 2372 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 56,579 psi | 89% | 2477 fps | 100% |
| Hodgdon H414 | <<locked>> | 84% | 56,608 psi | 89% | 2421 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 55,492 psi | 87% | 2385 fps | 100% |
| Hodgdon H4831 | <<locked>> | 92% | 56,985 psi | 89% | 2431 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 92% | 55,840 psi | 88% | 2418 fps | 99.5% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 56,159 psi | 88% | 2349 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 56,695 psi | 89% | 2575 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 56,942 psi | 89% | 2457 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,318 psi | 58% | 1470 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 55,172 psi | 86% | 2362 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 55,056 psi | 86% | 2346 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 55,172 psi | 86% | 2362 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 54,447 psi | 85% | 2372 fps | 99.4% |
| IMR 7828 SSC | <<locked>> | 94% | 54,984 psi | 86% | 2470 fps | 99.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 41,336 psi | 65% | 2310 fps | 98.4% |
| Lovex S065 | <<locked>> | 84% | 55,709 psi | 87% | 2343 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 57,276 psi | 90% | 2385 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 54,868 psi | 86% | 2369 fps | 100% |
| Norma 204 | <<locked>> | 86% | 56,173 psi | 88% | 2415 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 41,452 psi | 65% | 2329 fps | 99.8% |
| Norma MRP | <<locked>> | 92% | 57,087 psi | 89% | 2497 fps | 100% |
| Norma URP | <<locked>> | 86% | 56,840 psi | 89% | 2398 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 55,883 psi | 88% | 2490 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 55,811 psi | 87% | 2411 fps | 100% |
| Ramshot Magnum | <<locked>> | 96% | 54,070 psi | 85% | 2431 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,130 psi | 60% | 1503 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 54,839 psi | 86% | 2392 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 57,159 psi | 90% | 2467 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 57,580 psi | 90% | 2575 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 52,359 psi | 82% | 2490 fps | 99.3% |
| Rottweil R 904 | <<locked>> | 90% | 56,666 psi | 89% | 2402 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 90% | 54,766 psi | 86% | 2411 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 57,014 psi | 89% | 2372 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 55,709 psi | 87% | 2343 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 57,276 psi | 90% | 2385 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 54,737 psi | 86% | 2306 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 54,346 psi | 85% | 2408 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 54,549 psi | 85% | 2352 fps | 99.3% |
| Somchem S365 | <<locked>> | 88% | 57,537 psi | 90% | 2398 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 55,114 psi | 86% | 2385 fps | 100% |
| Vihtavuori N150 | <<locked>> | 82% | 55,666 psi | 87% | 2287 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 55,158 psi | 86% | 2349 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 54,723 psi | 86% | 2372 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 56,913 psi | 89% | 2431 fps | 96.8% |
| Vihtavuori N550 | <<locked>> | 84% | 54,346 psi | 85% | 2359 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 57,130 psi | 90% | 2421 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 56,811 psi | 89% | 2500 fps | 99.7% |
| Vihtavuori N565 | <<locked>> | 98% | 56,710 psi | 89% | 2487 fps | 99.8% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 53,563 psi | 84% | 2493 fps | 99% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 50,430 psi | 79% | 2487 fps | 97% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 54,389 psi | 85% | 2313 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 56,608 psi | 89% | 2421 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 96% | 56,855 psi | 89% | 2523 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 54,984 psi | 86% | 2385 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% | 35,984 psi | 56% | 2093 fps | 99.4% |
| Accurate 4350 | <<locked>> | 80% | 48,037 psi | 75% | 2283 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 36,709 psi | 58% | 2185 fps | 95.4% |
| ADI AR 2209 | <<locked>> | 80% | 40,030 psi | 63% | 2198 fps | 98.5% |
| ADI AR 2213 | <<locked>> | 80% | 35,665 psi | 56% | 2142 fps | 96.1% |
| ADI AR 2217 | <<locked>> | 88% | 34,606 psi | 54% | 2123 fps | 96% |
| ADI AR 2225 | <<locked>> | 84% | 27,398 psi | 43% | 1998 fps | 95.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 45,963 psi | 72% | 2290 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 53,127 psi | 83% | 2382 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 40,016 psi | 63% | 2192 fps | 98.5% |
| Alliant Reloder-22 | <<locked>> | 80% | 35,839 psi | 56% | 2152 fps | 97.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 34,621 psi | 54% | 2116 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 30,095 psi | 47% | 2057 fps | 98.8% |
| Alliant Reloder-26 | 69.9 gr | 80% | 38,000 psi | 60% | 2241 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 44,063 psi | 69% | 2372 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 42,960 psi | 67% | 2221 fps | 95.1% |
| Bofors RP15 | <<locked>> | 80% | 33,417 psi | 52% | 2100 fps | 96.7% |
| Bofors RP30 | <<locked>> | 84% | 31,444 psi | 49% | 2090 fps | 95.2% |
| Bofors RP5 | <<locked>> | 80% | 35,839 psi | 56% | 2152 fps | 97.6% |
| Bofors RP7 | <<locked>> | 80% | 50,314 psi | 79% | 2283 fps | 100% |
| Hodgdon H1000 | <<locked>> | 84% | 32,880 psi | 52% | 2087 fps | 95.9% |
| Hodgdon H414 | <<locked>> | 80% | 49,559 psi | 78% | 2329 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 51,967 psi | 81% | 2339 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 80% | 38,145 psi | 60% | 2149 fps | 96.3% |
| Hodgdon H4831 SC | <<locked>> | 80% | 37,362 psi | 59% | 2133 fps | 96% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 43,453 psi | 68% | 2192 fps | 100% |
| Hodgdon Retumbo | 65.4 gr | 80% | 29,399 psi | 46% | 2073 fps | 95.6% |
| Hodgdon Superformance | <<locked>> | 80% | 49,284 psi | 77% | 2359 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,949 psi | 44% | 1312 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 45,861 psi | 72% | 2238 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 80% | 51,590 psi | 81% | 2303 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 45,614 psi | 71% | 2241 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 39,827 psi | 62% | 2146 fps | 96.9% |
| IMR 7828 SSC | <<locked>> | 80% | 34,403 psi | 54% | 2126 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 92% | 31,966 psi | 50% | 2119 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 49,298 psi | 77% | 2260 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 47,630 psi | 75% | 2260 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 31,140 psi | 49% | 1998 fps | 98.3% |
| Norma 204 | <<locked>> | 80% | 45,832 psi | 72% | 2274 fps | 99.3% |
| Norma 217 | <<locked>> | 88% | 27,978 psi | 44% | 2044 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 37,666 psi | 59% | 2211 fps | 99.2% |
| Norma URP | <<locked>> | 80% | 46,963 psi | 74% | 2274 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 33,895 psi | 53% | 2129 fps | 96% |
| Ramshot Hunter | <<locked>> | 80% | 45,730 psi | 72% | 2277 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 30,124 psi | 47% | 2034 fps | 96.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,572 psi | 45% | 1342 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 47,921 psi | 75% | 2306 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 46,151 psi | 72% | 2326 fps | 100% |
| ReloadSwiss RS 76 | 70 gr | 80% | 28,282 psi | 44% | 2051 fps | 96.3% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 36,201 psi | 57% | 2224 fps | 95.5% |
| Rottweil R 904 | <<locked>> | 80% | 41,307 psi | 65% | 2178 fps | 97.8% |
| Rottweil R 905 | <<locked>> | 80% | 39,392 psi | 62% | 2182 fps | 98.5% |
| Rottweil R 907 | <<locked>> | 80% | 50,314 psi | 79% | 2283 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 49,298 psi | 77% | 2260 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 47,630 psi | 75% | 2260 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 48,298 psi | 76% | 2224 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 39,059 psi | 61% | 2178 fps | 98.4% |
| Somchem S361 | <<locked>> | 80% | 42,003 psi | 66% | 2169 fps | 97.3% |
| Somchem S365 | <<locked>> | 80% | 44,193 psi | 69% | 2238 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 39,914 psi | 63% | 2165 fps | 99.1% |
| Vihtavuori N150 | <<locked>> | 80% | 52,315 psi | 82% | 2251 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 48,385 psi | 76% | 2264 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 34,650 psi | 54% | 2067 fps | 97.7% |
| Vihtavuori N170 | <<locked>> | 96% | 49,763 psi | 78% | 2336 fps | 95.2% |
| Vihtavuori N550 | <<locked>> | 80% | 47,645 psi | 75% | 2270 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 38,928 psi | 61% | 2175 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 37,753 psi | 59% | 2205 fps | 96.4% |
| Vihtavuori N565 | <<locked>> | 82% | 33,170 psi | 52% | 2103 fps | 95% |
| Vihtavuori N568 | <<locked>> | 90% | 37,637 psi | 59% | 2234 fps | 95.3% |
| Vihtavuori N570 | <<locked>> | 96% | 43,874 psi | 69% | 2379 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 47,456 psi | 74% | 2231 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 49,719 psi | 78% | 2333 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 30,748 psi | 48% | 2149 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 36,492 psi | 57% | 2106 fps | 97.7% |
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 79 powders for .338 Rem. Ultra Mag. loaded with the .338 | 300gr | MAKER Expanding Subsonic. Hodgdon Retumbo delivers the highest muzzle velocity at 2,575 fps; across all powders the maximum-charge window runs from 1,470 fps to 2,575 fps. ADI AR 2217 gives the best case fill at 100 %, and 79 of the 79 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 58–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.338" calls for a 1:11.5 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, Alliant Reloder-26 rank at the top here: for .338 Rem. Ultra Mag. with the .338 | 300gr | MAKER Expanding Subsonic 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.