Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 250gr | Sako Hammerhead bullet and 74 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>> | 94% | 56,753 psi | 89% | 2631 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 54,302 psi | 85% | 2612 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 55,317 psi | 87% | 2723 fps | 98.6% |
| ADI AR 2209 | <<locked>> | 90% | 55,085 psi | 86% | 2664 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 94% | 56,420 psi | 88% | 2720 fps | 99.4% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 50,676 psi | 79% | 2631 fps | 99% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 45,281 psi | 71% | 2598 fps | 99.9% |
| Alliant Power Pro Varmint | <<locked>> | 90% | 55,187 psi | 86% | 2661 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 86% | 55,056 psi | 86% | 2657 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 56,159 psi | 88% | 2671 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 54,592 psi | 86% | 2654 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 94% | 56,507 psi | 89% | 2717 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 94% | 54,230 psi | 85% | 2638 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 57,174 psi | 90% | 2743 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 54,404 psi | 85% | 2720 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 54,520 psi | 85% | 2631 fps | 96.8% |
| Bofors RP15 | <<locked>> | 96% | 55,666 psi | 87% | 2703 fps | 99.8% |
| Bofors RP30ᴾ | <<locked>> | 100% | 53,142 psi | 83% | 2697 fps | 99.4% |
| Bofors RP5 | <<locked>> | 94% | 56,507 psi | 89% | 2717 fps | 99.9% |
| Bofors RP7 | <<locked>> | 84% | 56,318 psi | 88% | 2608 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 55,898 psi | 88% | 2710 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 84% | 55,869 psi | 88% | 2657 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 54,679 psi | 86% | 2618 fps | 99.8% |
| Hodgdon H4831 | <<locked>> | 92% | 56,333 psi | 88% | 2664 fps | 98.9% |
| Hodgdon H4831 SC | <<locked>> | 92% | 55,288 psi | 87% | 2648 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 55,405 psi | 87% | 2589 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 56,057 psi | 88% | 2815 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 56,318 psi | 88% | 2694 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,159 psi | 58% | 1650 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 54,607 psi | 86% | 2598 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 84% | 57,711 psi | 90% | 2628 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 54,621 psi | 86% | 2602 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 57,276 psi | 90% | 2648 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 94% | 54,447 psi | 85% | 2703 fps | 99.2% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 40,843 psi | 64% | 2510 fps | 97% |
| Lovex S065 | <<locked>> | 84% | 55,085 psi | 86% | 2582 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 56,811 psi | 89% | 2628 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 54,331 psi | 85% | 2598 fps | 100% |
| Norma 204 | <<locked>> | 86% | 55,492 psi | 87% | 2648 fps | 99.7% |
| Norma 217ᴾ | <<locked>> | 100% | 40,988 psi | 64% | 2533 fps | 99% |
| Norma MRP | <<locked>> | 92% | 56,637 psi | 89% | 2740 fps | 100% |
| Norma URP | <<locked>> | 86% | 56,333 psi | 88% | 2641 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 55,085 psi | 86% | 2720 fps | 99.5% |
| Ramshot Hunter | <<locked>> | 86% | 55,100 psi | 86% | 2648 fps | 100% |
| Ramshot Magnum | <<locked>> | 98% | 57,653 psi | 90% | 2710 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,000 psi | 60% | 1690 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 54,273 psi | 85% | 2631 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 56,420 psi | 88% | 2707 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 57,159 psi | 90% | 2815 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 51,996 psi | 81% | 2717 fps | 98.4% |
| Rottweil R 904 | <<locked>> | 90% | 56,086 psi | 88% | 2635 fps | 99.3% |
| Rottweil R 905 | <<locked>> | 92% | 57,740 psi | 90% | 2694 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 84% | 56,318 psi | 88% | 2608 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 55,085 psi | 86% | 2582 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 56,811 psi | 89% | 2628 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 57,392 psi | 90% | 2480 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 54,114 psi | 85% | 2536 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 57,290 psi | 90% | 2690 fps | 99.9% |
| Somchem S355 | <<locked>> | 82% | 57,479 psi | 90% | 2598 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 57,682 psi | 90% | 2628 fps | 99% |
| Somchem S365 | <<locked>> | 88% | 56,855 psi | 89% | 2641 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 54,578 psi | 86% | 2618 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 82% | 55,085 psi | 86% | 2526 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 54,447 psi | 85% | 2585 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 54,157 psi | 85% | 2602 fps | 99.8% |
| Vihtavuori N550 | <<locked>> | 86% | 57,101 psi | 89% | 2638 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 56,492 psi | 89% | 2664 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 56,405 psi | 88% | 2736 fps | 99.1% |
| Vihtavuori N565 | <<locked>> | 98% | 56,318 psi | 88% | 2717 fps | 99.3% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 53,098 psi | 83% | 2720 fps | 98% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 57,667 psi | 90% | 2592 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 56,057 psi | 88% | 2664 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 96% | 55,912 psi | 88% | 2762 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 54,404 psi | 85% | 2615 fps | 99.7% |
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% | 35,433 psi | 56% | 2290 fps | 98.4% |
| Accurate 4350 | <<locked>> | 80% | 47,369 psi | 74% | 2513 fps | 100% |
| Accurate MAGPRO | 82.5 gr | 84% | 41,800 psi | 66% | 2497 fps | 95.5% |
| ADI AR 2209 | <<locked>> | 80% | 39,407 psi | 62% | 2402 fps | 97.1% |
| ADI AR 2213 | <<locked>> | 82% | 37,579 psi | 59% | 2392 fps | 95.1% |
| ADI AR 2217 | <<locked>> | 92% | 38,798 psi | 61% | 2415 fps | 96% |
| ADI AR 2225 | <<locked>> | 88% | 30,734 psi | 48% | 2274 fps | 95.9% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 39,842 psi | 62% | 2405 fps | 97.3% |
| Alliant Reloder-16 | <<locked>> | 80% | 45,165 psi | 71% | 2516 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 52,431 psi | 82% | 2621 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 39,479 psi | 62% | 2398 fps | 97.2% |
| Alliant Reloder-22 | <<locked>> | 80% | 35,288 psi | 55% | 2349 fps | 96% |
| Alliant Reloder-23 | <<locked>> | 80% | 34,026 psi | 53% | 2313 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 29,588 psi | 46% | 2234 fps | 97.2% |
| Alliant Reloder-26 | 79.4 gr | 80% | 37,304 psi | 58% | 2441 fps | 99.7% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 48,138 psi | 75% | 2526 fps | 95.2% |
| Bofors RP15 | <<locked>> | 82% | 35,143 psi | 55% | 2343 fps | 95.7% |
| Bofors RP30 | <<locked>> | 88% | 35,418 psi | 56% | 2379 fps | 95.2% |
| Bofors RP5 | <<locked>> | 80% | 35,288 psi | 55% | 2349 fps | 96% |
| Bofors RP7 | <<locked>> | 80% | 49,719 psi | 78% | 2513 fps | 99.6% |
| Hodgdon H1000 | <<locked>> | 88% | 37,188 psi | 58% | 2382 fps | 96% |
| Hodgdon H414 | <<locked>> | 80% | 48,878 psi | 77% | 2559 fps | 99.8% |
| Hodgdon H4350 | <<locked>> | 80% | 51,401 psi | 81% | 2569 fps | 99.5% |
| Hodgdon H4831 | <<locked>> | 82% | 40,103 psi | 63% | 2395 fps | 95.4% |
| Hodgdon H4831 SC | <<locked>> | 82% | 39,392 psi | 62% | 2382 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 42,786 psi | 67% | 2411 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 84% | 32,938 psi | 52% | 2362 fps | 95.5% |
| Hodgdon Superformance | <<locked>> | 80% | 48,602 psi | 76% | 2582 fps | 99.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,876 psi | 44% | 1476 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 45,223 psi | 71% | 2454 fps | 99.2% |
| IMR 4451 Enduron | <<locked>> | 80% | 51,097 psi | 80% | 2536 fps | 99.9% |
| IMR 4831 | <<locked>> | 80% | 44,947 psi | 70% | 2464 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 39,276 psi | 62% | 2349 fps | 95.3% |
| IMR 7828 SSC | <<locked>> | 84% | 38,754 psi | 61% | 2428 fps | 95.7% |
| IMR 8133 Enduron | <<locked>> | 96% | 35,795 psi | 56% | 2405 fps | 95.1% |
| Lovex S065 | <<locked>> | 80% | 48,718 psi | 76% | 2490 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 47,094 psi | 74% | 2484 fps | 99.7% |
| Lovex S071 | <<locked>> | 80% | 30,574 psi | 48% | 2178 fps | 96.8% |
| Norma 204 | <<locked>> | 80% | 45,310 psi | 71% | 2490 fps | 98.4% |
| Norma 217 | <<locked>> | 92% | 31,459 psi | 49% | 2320 fps | 95.7% |
| Norma MRP | <<locked>> | 80% | 36,970 psi | 58% | 2411 fps | 98% |
| Norma URP | <<locked>> | 80% | 46,340 psi | 73% | 2500 fps | 100% |
| Ramshot Grand | 78.4 gr | 82% | 35,824 psi | 56% | 2375 fps | 95% |
| Ramshot Hunter | <<locked>> | 80% | 45,179 psi | 71% | 2497 fps | 99.8% |
| Ramshot Magnum | <<locked>> | 82% | 31,894 psi | 50% | 2267 fps | 95.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,543 psi | 45% | 1512 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 47,253 psi | 74% | 2530 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 45,455 psi | 71% | 2549 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 82% | 29,849 psi | 47% | 2277 fps | 95.1% |
| ReloadSwiss RS 80 | <<locked>> | 94% | 41,452 psi | 65% | 2533 fps | 95.7% |
| Rottweil R 904 | <<locked>> | 80% | 40,683 psi | 64% | 2382 fps | 96.4% |
| Rottweil R 905 | <<locked>> | 80% | 38,754 psi | 61% | 2385 fps | 97.2% |
| Rottweil R 907 | <<locked>> | 80% | 49,719 psi | 78% | 2513 fps | 99.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 48,718 psi | 76% | 2490 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 47,094 psi | 74% | 2484 fps | 99.7% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 54,085 psi | 85% | 2441 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 47,543 psi | 75% | 2441 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 38,464 psi | 60% | 2382 fps | 97.1% |
| Somchem S355 | <<locked>> | 80% | 53,998 psi | 85% | 2556 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 41,437 psi | 65% | 2372 fps | 95.8% |
| Somchem S365 | <<locked>> | 80% | 43,482 psi | 68% | 2461 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 39,378 psi | 62% | 2369 fps | 98.1% |
| Vihtavuori N150 | <<locked>> | 80% | 51,721 psi | 81% | 2484 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 47,776 psi | 75% | 2493 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 34,142 psi | 54% | 2257 fps | 96.1% |
| Vihtavuori N550 | <<locked>> | 80% | 47,137 psi | 74% | 2497 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 38,130 psi | 60% | 2382 fps | 99.9% |
| Vihtavuori N560 | <<locked>> | 82% | 39,755 psi | 62% | 2454 fps | 95.5% |
| Vihtavuori N565 | <<locked>> | 86% | 37,420 psi | 59% | 2395 fps | 95% |
| Vihtavuori N568 | <<locked>> | 94% | 42,888 psi | 67% | 2546 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 46,847 psi | 73% | 2454 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 49,052 psi | 77% | 2559 fps | 99.8% |
| Winchester StaBALL HD | <<locked>> | 80% | 30,284 psi | 47% | 2339 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 35,998 psi | 56% | 2300 fps | 96.1% |
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 74 powders for .338 Rem. Ultra Mag. loaded with the .338 | 250gr | Sako Hammerhead. Hodgdon Retumbo delivers the highest muzzle velocity at 2,815 fps; across all powders the maximum-charge window runs from 1,650 fps to 2,815 fps. ADI AR 2217 gives the best case fill at 100 %, and 74 of the 74 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 1:6.0 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 | Sako Hammerhead 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.