Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 225gr | Speer Grand Slam bullet and 76 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate MAGPRO, Alliant Reloder-26 and Ramshot Grand.
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% | 56,565 psi | 89% | 2756 fps | 100% |
| Accurate 4350 | <<locked>> | 86% | 54,128 psi | 85% | 2740 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 54,955 psi | 86% | 2841 fps | 97.7% |
| ADI AR 2208 | <<locked>> | 82% | 55,434 psi | 87% | 2707 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 54,853 psi | 86% | 2785 fps | 99.2% |
| ADI AR 2213 | <<locked>> | 96% | 56,362 psi | 88% | 2844 fps | 98.7% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 47,253 psi | 74% | 2684 fps | 97.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,989 psi | 66% | 2644 fps | 98.9% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 56,739 psi | 89% | 2726 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 54,897 psi | 86% | 2792 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 56,246 psi | 88% | 2808 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 92% | 54,476 psi | 85% | 2779 fps | 99.2% |
| Alliant Reloder-22 | <<locked>> | 96% | 56,217 psi | 88% | 2838 fps | 99.5% |
| Alliant Reloder-23 | <<locked>> | 98% | 57,203 psi | 90% | 2812 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 52,953 psi | 83% | 2815 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 92% | 53,911 psi | 84% | 2848 fps | 100% |
| Bofors RP15 | <<locked>> | 98% | 55,129 psi | 86% | 2822 fps | 99.3% |
| Bofors RP30ᴾ | <<locked>> | 100% | 48,950 psi | 77% | 2753 fps | 98.1% |
| Bofors RP5 | <<locked>> | 96% | 56,217 psi | 88% | 2838 fps | 99.5% |
| Bofors RP7 | <<locked>> | 86% | 56,768 psi | 89% | 2740 fps | 99.8% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 52,069 psi | 82% | 2769 fps | 98.8% |
| Hodgdon H414 | <<locked>> | 86% | 55,912 psi | 88% | 2789 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 84% | 55,071 psi | 86% | 2749 fps | 99.4% |
| Hodgdon H4831 | <<locked>> | 94% | 56,391 psi | 88% | 2785 fps | 98.1% |
| Hodgdon H4831 SC | <<locked>> | 94% | 55,187 psi | 86% | 2769 fps | 97.9% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 55,303 psi | 87% | 2717 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 51,851 psi | 81% | 2874 fps | 99.7% |
| Hodgdon Superformance | <<locked>> | 86% | 56,391 psi | 88% | 2822 fps | 99.9% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,854 psi | 58% | 1736 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 54,752 psi | 86% | 2726 fps | 99.7% |
| IMR 4451 Enduron | <<locked>> | 84% | 54,810 psi | 86% | 2713 fps | 99.8% |
| IMR 4831 | <<locked>> | 88% | 54,476 psi | 85% | 2730 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 57,493 psi | 90% | 2772 fps | 98.4% |
| IMR 7828 SSC | <<locked>> | 96% | 54,041 psi | 85% | 2818 fps | 98.5% |
| Lovex S065 | <<locked>> | 86% | 55,245 psi | 87% | 2710 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 56,956 psi | 89% | 2756 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,809 psi | 84% | 2717 fps | 100% |
| Norma 204 | <<locked>> | 88% | 55,796 psi | 87% | 2779 fps | 99.2% |
| Norma 217ᴾ | <<locked>> | 100% | 37,550 psi | 59% | 2572 fps | 97% |
| Norma MRP | <<locked>> | 94% | 56,130 psi | 88% | 2861 fps | 99.9% |
| Norma URP | <<locked>> | 88% | 56,304 psi | 88% | 2772 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 54,810 psi | 86% | 2838 fps | 98.9% |
| Ramshot Hunter | <<locked>> | 88% | 55,216 psi | 87% | 2779 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 57,290 psi | 90% | 2831 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,623 psi | 59% | 1778 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 57,508 psi | 90% | 2746 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 55,564 psi | 87% | 2792 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 86% | 54,056 psi | 85% | 2759 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 56,130 psi | 88% | 2838 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 52,504 psi | 82% | 2871 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 47,355 psi | 74% | 2753 fps | 96.2% |
| Rottweil R 903 | <<locked>> | 82% | 54,433 psi | 85% | 2694 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 56,304 psi | 88% | 2759 fps | 98.6% |
| Rottweil R 905 | <<locked>> | 94% | 57,624 psi | 90% | 2818 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 86% | 56,768 psi | 89% | 2740 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 86% | 55,245 psi | 87% | 2710 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 56,956 psi | 89% | 2756 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 56,014 psi | 88% | 2749 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 54,563 psi | 86% | 2575 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 54,679 psi | 86% | 2667 fps | 99.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 57,159 psi | 90% | 2815 fps | 99.5% |
| Somchem S355 | <<locked>> | 84% | 57,682 psi | 90% | 2733 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 54,273 psi | 85% | 2697 fps | 97.7% |
| Somchem S365 | <<locked>> | 90% | 56,550 psi | 89% | 2776 fps | 100% |
| Somchem S385 | <<locked>> | 92% | 54,418 psi | 85% | 2740 fps | 99.6% |
| Vihtavuori N150 | <<locked>> | 84% | 55,448 psi | 87% | 2661 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 54,520 psi | 85% | 2717 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 57,653 psi | 90% | 2769 fps | 99.7% |
| Vihtavuori N550 | <<locked>> | 88% | 57,421 psi | 90% | 2772 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 56,028 psi | 88% | 2789 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 55,956 psi | 88% | 2854 fps | 98.4% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 55,608 psi | 87% | 2831 fps | 98.5% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 53,954 psi | 85% | 2677 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 56,101 psi | 88% | 2792 fps | 99.9% |
| Winchester StaBALL HD | <<locked>> | 98% | 54,636 psi | 86% | 2887 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 54,433 psi | 85% | 2736 fps | 99.2% |
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% | 32,793 psi | 51% | 2339 fps | 96.5% |
| Accurate 4350 | <<locked>> | 80% | 44,063 psi | 69% | 2582 fps | 99.9% |
| Accurate MAGPRO | 87.6 gr | 88% | 44,483 psi | 70% | 2661 fps | 95.1% |
| ADI AR 2208 | <<locked>> | 80% | 52,127 psi | 82% | 2657 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,840 psi | 58% | 2457 fps | 95% |
| ADI AR 2213 | <<locked>> | 88% | 43,033 psi | 67% | 2615 fps | 95.7% |
| ADI AR 2217 | <<locked>> | 96% | 41,336 psi | 65% | 2569 fps | 95.4% |
| ADI AR 2225 | <<locked>> | 92% | 32,460 psi | 51% | 2415 fps | 95.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 53,330 psi | 84% | 2680 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 42,148 psi | 66% | 2589 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,631 psi | 76% | 2700 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,825 psi | 58% | 2454 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 84% | 37,478 psi | 59% | 2507 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,473 psi | 49% | 2369 fps | 99.2% |
| Alliant Reloder-25 | <<locked>> | 82% | 29,283 psi | 46% | 2323 fps | 95.5% |
| Alliant Reloder-26 | 80.5 gr | 80% | 34,200 psi | 54% | 2490 fps | 98.4% |
| Bofors RP15 | <<locked>> | 86% | 37,130 psi | 58% | 2497 fps | 95.2% |
| Bofors RP30 | <<locked>> | 94% | 39,842 psi | 62% | 2582 fps | 95.6% |
| Bofors RP5 | <<locked>> | 84% | 37,478 psi | 59% | 2507 fps | 95.5% |
| Bofors RP7 | <<locked>> | 80% | 47,007 psi | 74% | 2589 fps | 98.7% |
| Hodgdon H1000 | <<locked>> | 92% | 39,653 psi | 62% | 2539 fps | 95.5% |
| Hodgdon H414 | <<locked>> | 80% | 45,701 psi | 72% | 2625 fps | 98.9% |
| Hodgdon H4350 | <<locked>> | 80% | 48,370 psi | 76% | 2641 fps | 98.5% |
| Hodgdon H4831 | <<locked>> | 86% | 42,946 psi | 67% | 2562 fps | 95% |
| Hodgdon H4831 SC | <<locked>> | 88% | 45,165 psi | 71% | 2602 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 39,740 psi | 62% | 2480 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 37,188 psi | 58% | 2572 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 45,136 psi | 71% | 2648 fps | 98.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,586 psi | 43% | 1555 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,554 psi | 67% | 2520 fps | 97.9% |
| IMR 4451 Enduron | <<locked>> | 80% | 48,399 psi | 76% | 2612 fps | 99.2% |
| IMR 4831 | <<locked>> | 80% | 41,989 psi | 66% | 2533 fps | 99.8% |
| IMR 4955 Enduron | <<locked>> | 86% | 44,744 psi | 70% | 2566 fps | 95.8% |
| IMR 7828 SSC | <<locked>> | 88% | 41,220 psi | 65% | 2589 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 46,006 psi | 72% | 2566 fps | 99.6% |
| Lovex S070 | <<locked>> | 80% | 44,280 psi | 69% | 2552 fps | 98.8% |
| Lovex S071 | <<locked>> | 82% | 30,110 psi | 47% | 2274 fps | 95.4% |
| Norma 204 | <<locked>> | 80% | 42,337 psi | 66% | 2552 fps | 96.7% |
| Norma 217 | <<locked>> | 98% | 35,056 psi | 55% | 2513 fps | 96% |
| Norma MRP | <<locked>> | 80% | 34,055 psi | 53% | 2454 fps | 95.7% |
| Norma URP | <<locked>> | 80% | 43,337 psi | 68% | 2572 fps | 99.8% |
| Ramshot Grand | 85.2 gr | 88% | 40,930 psi | 64% | 2592 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 42,119 psi | 66% | 2562 fps | 98.9% |
| Ramshot Magnum | <<locked>> | 86% | 34,098 psi | 53% | 2421 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,195 psi | 44% | 1591 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 53,954 psi | 85% | 2700 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,619 psi | 81% | 2743 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 44,019 psi | 69% | 2602 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 42,264 psi | 66% | 2615 fps | 99.7% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 34,055 psi | 53% | 2490 fps | 95.9% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 43,990 psi | 69% | 2690 fps | 95.2% |
| Rottweil R 903 | <<locked>> | 80% | 51,097 psi | 80% | 2648 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 40,814 psi | 64% | 2497 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 80% | 36,013 psi | 56% | 2438 fps | 95% |
| Rottweil R 907 | <<locked>> | 80% | 47,007 psi | 74% | 2589 fps | 98.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 46,006 psi | 72% | 2566 fps | 99.6% |
| Shooters World SW4350 | <<locked>> | 80% | 44,280 psi | 69% | 2552 fps | 98.8% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 52,301 psi | 82% | 2697 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 51,256 psi | 80% | 2536 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,918 psi | 70% | 2513 fps | 98.8% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 38,276 psi | 60% | 2490 fps | 95.8% |
| Somchem S355 | <<locked>> | 80% | 50,995 psi | 80% | 2644 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 44,541 psi | 70% | 2536 fps | 95.5% |
| Somchem S365 | <<locked>> | 80% | 40,205 psi | 63% | 2533 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,695 psi | 57% | 2425 fps | 96.2% |
| Vihtavuori N150 | <<locked>> | 80% | 48,791 psi | 76% | 2572 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,744 psi | 70% | 2569 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 84% | 36,216 psi | 57% | 2408 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 44,121 psi | 69% | 2569 fps | 99.8% |
| Vihtavuori N555 | <<locked>> | 80% | 35,201 psi | 55% | 2438 fps | 99.1% |
| Vihtavuori N560 | <<locked>> | 86% | 42,366 psi | 66% | 2618 fps | 95.1% |
| Vihtavuori N565 | <<locked>> | 92% | 42,409 psi | 66% | 2608 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,830 psi | 69% | 2530 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 45,861 psi | 72% | 2628 fps | 99% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,876 psi | 44% | 2369 fps | 99.2% |
| Winchester Supreme 780 | <<locked>> | 84% | 38,392 psi | 60% | 2461 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 76 powders for .338 Rem. Ultra Mag. loaded with the .338 | 225gr | Speer Grand Slam. Winchester StaBALL HD delivers the highest muzzle velocity at 2,887 fps; across all powders the maximum-charge window runs from 1,736 fps to 2,887 fps. ADI AR 2217 gives the best case fill at 100 %, and 76 of the 76 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 225.0 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, Alliant Reloder-26, Ramshot Grand rank at the top here: for .338 Rem. Ultra Mag. with the .338 | 225gr | Speer Grand Slam 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.