Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 250gr | Prvi Partizan FMJ-BT bullet and 77 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate MAGPRO, Ramshot Grand 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.
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Max Load - Barrel Length: 24"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 96% | 56,550 psi | 89% | 2618 fps | 100% |
| Accurate 4350 | <<locked>> | 86% | 54,302 psi | 85% | 2602 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 54,984 psi | 86% | 2707 fps | 98.3% |
| ADI AR 2208 | <<locked>> | 82% | 55,579 psi | 87% | 2562 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 55,085 psi | 86% | 2654 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 96% | 56,449 psi | 88% | 2707 fps | 99.2% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 47,181 psi | 74% | 2559 fps | 98% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,959 psi | 66% | 2526 fps | 99.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 57,014 psi | 89% | 2585 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 55,027 psi | 86% | 2648 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 56,217 psi | 88% | 2664 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 92% | 54,563 psi | 86% | 2641 fps | 99.5% |
| Alliant Reloder-22 | <<locked>> | 96% | 56,304 psi | 88% | 2703 fps | 99.8% |
| Alliant Reloder-23 | <<locked>> | 98% | 57,406 psi | 90% | 2671 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 52,968 psi | 83% | 2680 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 92% | 53,838 psi | 84% | 2707 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 54,868 psi | 86% | 2618 fps | 96.4% |
| Bofors RP15 | <<locked>> | 98% | 55,216 psi | 87% | 2687 fps | 99.6% |
| Bofors RP30ᴾ | <<locked>> | 100% | 48,791 psi | 76% | 2621 fps | 98.6% |
| Bofors RP5 | <<locked>> | 96% | 56,304 psi | 88% | 2703 fps | 99.8% |
| Bofors RP7 | <<locked>> | 86% | 56,898 psi | 89% | 2602 fps | 99.9% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 52,040 psi | 82% | 2638 fps | 99.2% |
| Hodgdon H414 | <<locked>> | 86% | 55,912 psi | 88% | 2648 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 55,100 psi | 86% | 2612 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 94% | 56,521 psi | 89% | 2651 fps | 98.6% |
| Hodgdon H4831 SC | <<locked>> | 94% | 55,259 psi | 87% | 2635 fps | 98.5% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 55,419 psi | 87% | 2575 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 51,793 psi | 81% | 2740 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 86% | 56,449 psi | 88% | 2684 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,043 psi | 58% | 1627 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 54,897 psi | 86% | 2589 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 84% | 54,969 psi | 86% | 2575 fps | 99.9% |
| IMR 4831 | <<locked>> | 88% | 54,592 psi | 86% | 2592 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 57,551 psi | 90% | 2635 fps | 98.9% |
| IMR 7828 SSC | <<locked>> | 96% | 54,085 psi | 85% | 2684 fps | 98.9% |
| Lovex S065 | <<locked>> | 86% | 55,521 psi | 87% | 2572 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 57,072 psi | 89% | 2615 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,780 psi | 84% | 2582 fps | 100% |
| Norma 204 | <<locked>> | 88% | 55,724 psi | 87% | 2638 fps | 99.5% |
| Norma 217ᴾ | <<locked>> | 100% | 37,492 psi | 59% | 2457 fps | 97.8% |
| Norma MRP | <<locked>> | 94% | 56,115 psi | 88% | 2723 fps | 100% |
| Norma URP | <<locked>> | 88% | 56,362 psi | 88% | 2631 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 54,795 psi | 86% | 2703 fps | 99.3% |
| Ramshot Hunter | <<locked>> | 88% | 55,172 psi | 86% | 2641 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 57,188 psi | 90% | 2697 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,724 psi | 59% | 1663 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 55,753 psi | 87% | 2651 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 54,302 psi | 85% | 2621 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 56,260 psi | 88% | 2697 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 52,460 psi | 82% | 2740 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 47,253 psi | 74% | 2631 fps | 97% |
| Rottweil R 903 | <<locked>> | 82% | 54,549 psi | 85% | 2552 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 56,405 psi | 88% | 2625 fps | 99.1% |
| Rottweil R 905 | <<locked>> | 94% | 57,667 psi | 90% | 2680 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 86% | 56,898 psi | 89% | 2602 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 86% | 55,521 psi | 87% | 2572 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 57,072 psi | 89% | 2615 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 56,014 psi | 88% | 2605 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 54,592 psi | 86% | 2434 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 54,636 psi | 86% | 2530 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 57,217 psi | 90% | 2677 fps | 99.8% |
| Somchem S355 | <<locked>> | 82% | 54,433 psi | 85% | 2549 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 54,404 psi | 85% | 2566 fps | 98.3% |
| Somchem S365 | <<locked>> | 90% | 56,521 psi | 89% | 2631 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 54,636 psi | 86% | 2605 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 84% | 55,637 psi | 87% | 2523 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 54,621 psi | 86% | 2579 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 57,696 psi | 90% | 2635 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 88% | 57,421 psi | 90% | 2631 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 55,956 psi | 88% | 2648 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 56,014 psi | 88% | 2720 fps | 98.9% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 55,579 psi | 87% | 2697 fps | 99% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 48,559 psi | 76% | 2638 fps | 96.7% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 54,085 psi | 85% | 2539 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 56,130 psi | 88% | 2651 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 98% | 54,592 psi | 86% | 2749 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 54,404 psi | 85% | 2602 fps | 99.5% |
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% | 32,924 psi | 52% | 2228 fps | 97.4% |
| Accurate 4350 | <<locked>> | 80% | 44,280 psi | 69% | 2454 fps | 100% |
| Accurate MAGPRO | 79.4 gr | 86% | 41,452 psi | 65% | 2480 fps | 95% |
| ADI AR 2208 | <<locked>> | 80% | 52,243 psi | 82% | 2520 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,985 psi | 58% | 2339 fps | 96% |
| ADI AR 2213 | <<locked>> | 86% | 40,292 psi | 63% | 2434 fps | 95.7% |
| ADI AR 2217 | <<locked>> | 94% | 38,624 psi | 61% | 2395 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 90% | 30,501 psi | 48% | 2257 fps | 95.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 53,388 psi | 84% | 2539 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 42,438 psi | 67% | 2461 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,892 psi | 77% | 2566 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,999 psi | 58% | 2339 fps | 96.1% |
| Alliant Reloder-22 | <<locked>> | 82% | 35,128 psi | 55% | 2339 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,618 psi | 50% | 2257 fps | 99.7% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,615 psi | 43% | 2172 fps | 95.7% |
| Alliant Reloder-26 | 74.7 gr | 80% | 34,345 psi | 54% | 2375 fps | 99.1% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 51,663 psi | 81% | 2566 fps | 95.6% |
| Bofors RP15 | <<locked>> | 84% | 34,969 psi | 55% | 2333 fps | 95.3% |
| Bofors RP30 | <<locked>> | 92% | 37,289 psi | 58% | 2411 fps | 95.6% |
| Bofors RP5 | <<locked>> | 82% | 35,128 psi | 55% | 2339 fps | 95.6% |
| Bofors RP7 | <<locked>> | 80% | 47,195 psi | 74% | 2457 fps | 99.2% |
| Hodgdon H1000 | <<locked>> | 90% | 37,014 psi | 58% | 2362 fps | 95.4% |
| Hodgdon H414 | <<locked>> | 80% | 45,934 psi | 72% | 2500 fps | 99.4% |
| Hodgdon H4350 | <<locked>> | 80% | 48,472 psi | 76% | 2510 fps | 99% |
| Hodgdon H4831 | <<locked>> | 84% | 40,219 psi | 63% | 2388 fps | 95% |
| Hodgdon H4831 SC | <<locked>> | 86% | 42,264 psi | 66% | 2425 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 40,001 psi | 63% | 2356 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 34,867 psi | 55% | 2402 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 45,208 psi | 71% | 2516 fps | 99.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,673 psi | 43% | 1453 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,656 psi | 67% | 2395 fps | 98.5% |
| IMR 4451 Enduron | <<locked>> | 80% | 48,443 psi | 76% | 2477 fps | 99.5% |
| IMR 4831 | <<locked>> | 80% | 42,134 psi | 66% | 2405 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 42,134 psi | 66% | 2388 fps | 95.8% |
| IMR 7828 SSC | <<locked>> | 86% | 38,667 psi | 61% | 2415 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 46,166 psi | 72% | 2438 fps | 99.9% |
| Lovex S070 | <<locked>> | 80% | 44,382 psi | 70% | 2425 fps | 99.2% |
| Lovex S071 | <<locked>> | 80% | 28,355 psi | 44% | 2119 fps | 95.5% |
| Norma 204 | <<locked>> | 80% | 42,467 psi | 67% | 2428 fps | 97.5% |
| Norma 217 | <<locked>> | 96% | 32,909 psi | 52% | 2349 fps | 96% |
| Norma MRP | <<locked>> | 80% | 34,229 psi | 54% | 2343 fps | 96.7% |
| Norma URP | <<locked>> | 80% | 43,424 psi | 68% | 2444 fps | 100% |
| Ramshot Grand | 77.3 gr | 86% | 38,276 psi | 60% | 2418 fps | 95.5% |
| Ramshot Hunter | <<locked>> | 80% | 42,206 psi | 66% | 2438 fps | 99.4% |
| Ramshot Magnum | <<locked>> | 84% | 31,778 psi | 50% | 2254 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,355 psi | 44% | 1490 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,909 psi | 81% | 2602 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 44,106 psi | 69% | 2474 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 42,337 psi | 66% | 2487 fps | 99.9% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 31,836 psi | 50% | 2323 fps | 95.8% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 40,669 psi | 64% | 2510 fps | 95% |
| Rottweil R 903 | <<locked>> | 80% | 51,169 psi | 80% | 2507 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 38,392 psi | 60% | 2323 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 80% | 36,143 psi | 57% | 2323 fps | 96% |
| Rottweil R 907 | <<locked>> | 80% | 47,195 psi | 74% | 2457 fps | 99.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 46,166 psi | 72% | 2438 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 80% | 44,382 psi | 70% | 2425 fps | 99.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 52,446 psi | 82% | 2559 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 51,430 psi | 81% | 2398 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 45,049 psi | 71% | 2385 fps | 99.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,824 psi | 56% | 2316 fps | 95.8% |
| Somchem S355 | <<locked>> | 80% | 51,155 psi | 80% | 2503 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 41,756 psi | 65% | 2365 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 40,350 psi | 63% | 2405 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,796 psi | 58% | 2310 fps | 97.1% |
| Vihtavuori N150 | <<locked>> | 80% | 48,863 psi | 77% | 2434 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,933 psi | 70% | 2438 fps | 100% |
| Vihtavuori N165 | <<locked>> | 82% | 34,026 psi | 53% | 2244 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 44,324 psi | 69% | 2441 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 35,389 psi | 55% | 2323 fps | 99.6% |
| Vihtavuori N560 | <<locked>> | 84% | 39,581 psi | 62% | 2441 fps | 95.1% |
| Vihtavuori N565 | <<locked>> | 90% | 39,581 psi | 62% | 2431 fps | 95.4% |
| Vihtavuori N568 | <<locked>> | 98% | 45,295 psi | 71% | 2582 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,976 psi | 69% | 2402 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 46,093 psi | 72% | 2500 fps | 99.4% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,992 psi | 44% | 2267 fps | 99.8% |
| Winchester Supreme 780 | <<locked>> | 82% | 35,882 psi | 56% | 2290 fps | 95.7% |
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 82 powders for .338 Rem. Ultra Mag. loaded with the .338 | 250gr | Prvi Partizan FMJ-BT. Winchester StaBALL HD delivers the highest muzzle velocity at 2,749 fps; across all powders the maximum-charge window runs from 1,627 fps to 2,749 fps. ADI AR 2217 gives the best case fill at 100 %, and 82 of the 82 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 250.0 gr projectile in 0.338" calls for a 1:12.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Alliant Reloder-25 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. Accurate MAGPRO, Ramshot Grand, Alliant Reloder-26 rank at the top here: for .338 Rem. Ultra Mag. with the .338 | 250gr | Prvi Partizan FMJ-BT they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-33, IMR 7977 Enduron, Vihtavuori N170 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.