Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 250gr | Sierra MatchKing bullet and 80 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Vihtavuori N560, Norma MRP and Accurate MAGPRO.
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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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>> | 96% | 55,999 psi | 88% | 2608 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 57,609 psi | 90% | 2638 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 54,288 psi | 85% | 2694 fps | 98.1% |
| ADI AR 2208 | <<locked>> | 82% | 55,172 psi | 86% | 2556 fps | 100% |
| ADI AR 2209 | <<locked>> | 92% | 54,534 psi | 85% | 2641 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 96% | 55,767 psi | 87% | 2697 fps | 99% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 46,789 psi | 73% | 2546 fps | 97.8% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,568 psi | 65% | 2513 fps | 99.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 56,376 psi | 88% | 2572 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 54,607 psi | 86% | 2641 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 55,796 psi | 87% | 2654 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 57,566 psi | 90% | 2680 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 96% | 55,550 psi | 87% | 2690 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 98% | 56,623 psi | 89% | 2661 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 52,257 psi | 82% | 2667 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 57,246 psi | 90% | 2749 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 54,360 psi | 85% | 2605 fps | 96.2% |
| Bofors RP15 | <<locked>> | 98% | 54,737 psi | 86% | 2680 fps | 99.6% |
| Bofors RP3 | <<locked>> | 82% | 57,624 psi | 90% | 2592 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 48,312 psi | 76% | 2612 fps | 98.5% |
| Bofors RP5 | <<locked>> | 96% | 55,550 psi | 87% | 2690 fps | 99.7% |
| Bofors RP7 | <<locked>> | 86% | 56,536 psi | 89% | 2592 fps | 99.9% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 51,401 psi | 81% | 2625 fps | 99.1% |
| Hodgdon H380 | <<locked>> | 82% | 57,537 psi | 90% | 2612 fps | 100% |
| Hodgdon H414 | <<locked>> | 86% | 55,579 psi | 87% | 2641 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 54,752 psi | 86% | 2602 fps | 99.6% |
| Hodgdon H4831 | <<locked>> | 94% | 55,825 psi | 87% | 2638 fps | 98.5% |
| Hodgdon H4831 SC | <<locked>> | 94% | 54,766 psi | 86% | 2625 fps | 98.3% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 54,984 psi | 86% | 2569 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 51,314 psi | 80% | 2730 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 86% | 55,927 psi | 88% | 2674 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,927 psi | 58% | 1624 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 54,549 psi | 85% | 2582 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 84% | 54,578 psi | 86% | 2569 fps | 99.9% |
| IMR 4831 | <<locked>> | 88% | 54,244 psi | 85% | 2585 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 57,087 psi | 89% | 2625 fps | 98.8% |
| IMR 7828 SSC | <<locked>> | 98% | 57,276 psi | 90% | 2726 fps | 99.3% |
| Lovex S065 | <<locked>> | 86% | 54,984 psi | 86% | 2562 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 56,492 psi | 89% | 2605 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 53,258 psi | 83% | 2572 fps | 100% |
| Norma 204 | <<locked>> | 88% | 55,172 psi | 86% | 2628 fps | 99.4% |
| Norma 217ᴾ | <<locked>> | 100% | 37,057 psi | 58% | 2444 fps | 97.6% |
| Norma MRP | <<locked>> | 94% | 55,376 psi | 87% | 2713 fps | 100% |
| Norma URP | <<locked>> | 88% | 55,782 psi | 87% | 2621 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 54,070 psi | 85% | 2690 fps | 99.2% |
| Ramshot Hunter | <<locked>> | 88% | 54,607 psi | 86% | 2628 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 56,507 psi | 89% | 2687 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,782 psi | 59% | 1663 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 57,203 psi | 90% | 2598 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 55,288 psi | 87% | 2644 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 57,464 psi | 90% | 2661 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 55,695 psi | 87% | 2687 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 51,648 psi | 81% | 2723 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 46,644 psi | 73% | 2615 fps | 96.8% |
| Rottweil R 903 | <<locked>> | 84% | 57,711 psi | 90% | 2589 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 55,869 psi | 88% | 2612 fps | 99% |
| Rottweil R 905 | <<locked>> | 94% | 57,116 psi | 90% | 2671 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 86% | 56,536 psi | 89% | 2592 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 86% | 54,984 psi | 86% | 2562 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 56,492 psi | 89% | 2605 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 55,622 psi | 87% | 2598 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 54,418 psi | 85% | 2431 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 54,317 psi | 85% | 2523 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 56,652 psi | 89% | 2667 fps | 99.7% |
| Somchem S355 | <<locked>> | 84% | 57,319 psi | 90% | 2582 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 57,595 psi | 90% | 2608 fps | 98.7% |
| Somchem S365 | <<locked>> | 90% | 56,144 psi | 88% | 2625 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 57,667 psi | 90% | 2644 fps | 100% |
| Vihtavuori N150 | <<locked>> | 84% | 55,056 psi | 86% | 2513 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 54,070 psi | 85% | 2569 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 57,174 psi | 90% | 2625 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 88% | 56,869 psi | 89% | 2621 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 55,347 psi | 87% | 2641 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 55,288 psi | 87% | 2707 fps | 98.7% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 54,897 psi | 86% | 2687 fps | 98.8% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 47,964 psi | 75% | 2625 fps | 96.5% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 57,290 psi | 90% | 2575 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 55,782 psi | 87% | 2644 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 98% | 53,722 psi | 84% | 2736 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 57,682 psi | 90% | 2641 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% | 32,576 psi | 51% | 2221 fps | 97.2% |
| Accurate 4350 | <<locked>> | 80% | 43,845 psi | 69% | 2444 fps | 100% |
| Accurate MAGPRO | 80.5 gr | 88% | 43,918 psi | 69% | 2526 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 80% | 52,011 psi | 82% | 2513 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,651 psi | 57% | 2333 fps | 95.8% |
| ADI AR 2213 | <<locked>> | 86% | 39,856 psi | 62% | 2425 fps | 95.5% |
| ADI AR 2217 | <<locked>> | 94% | 38,232 psi | 60% | 2385 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 92% | 32,082 psi | 50% | 2297 fps | 96% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 53,127 psi | 83% | 2533 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 42,047 psi | 66% | 2454 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,283 psi | 76% | 2556 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,651 psi | 57% | 2329 fps | 95.9% |
| Alliant Reloder-22 | <<locked>> | 82% | 34,780 psi | 55% | 2329 fps | 95.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,285 psi | 49% | 2247 fps | 99.6% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,354 psi | 43% | 2162 fps | 95.4% |
| Alliant Reloder-26 | <<locked>> | 80% | 33,837 psi | 53% | 2365 fps | 99% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 51,140 psi | 80% | 2556 fps | 95.4% |
| Bofors RP15 | <<locked>> | 84% | 34,505 psi | 54% | 2320 fps | 95% |
| Bofors RP3 | <<locked>> | 80% | 53,867 psi | 84% | 2546 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 36,840 psi | 58% | 2402 fps | 95.3% |
| Bofors RP5 | <<locked>> | 82% | 34,780 psi | 55% | 2329 fps | 95.4% |
| Bofors RP7 | <<locked>> | 80% | 46,804 psi | 73% | 2448 fps | 99.1% |
| Hodgdon H1000 | <<locked>> | 90% | 36,622 psi | 57% | 2352 fps | 95.2% |
| Hodgdon H380 | <<locked>> | 80% | 53,998 psi | 85% | 2566 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 45,527 psi | 71% | 2490 fps | 99.3% |
| Hodgdon H4350 | <<locked>> | 80% | 48,095 psi | 75% | 2500 fps | 98.9% |
| Hodgdon H4831 | <<locked>> | 86% | 42,583 psi | 67% | 2428 fps | 95.7% |
| Hodgdon H4831 SC | <<locked>> | 86% | 41,785 psi | 65% | 2415 fps | 95.4% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 39,581 psi | 62% | 2349 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 34,592 psi | 54% | 2388 fps | 95.8% |
| Hodgdon Superformance | <<locked>> | 80% | 44,831 psi | 70% | 2510 fps | 99.1% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,644 psi | 43% | 1450 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,308 psi | 66% | 2388 fps | 98.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 48,254 psi | 76% | 2470 fps | 99.5% |
| IMR 4831 | <<locked>> | 80% | 41,727 psi | 65% | 2398 fps | 99.9% |
| IMR 4955 Enduron | <<locked>> | 84% | 41,684 psi | 65% | 2379 fps | 95.6% |
| IMR 7828 SSC | <<locked>> | 86% | 38,363 psi | 60% | 2405 fps | 95% |
| Lovex S065 | <<locked>> | 80% | 45,788 psi | 72% | 2428 fps | 99.8% |
| Lovex S070 | <<locked>> | 80% | 44,005 psi | 69% | 2418 fps | 99.2% |
| Lovex S071 | <<locked>> | 80% | 28,007 psi | 44% | 2110 fps | 95.3% |
| Norma 204 | <<locked>> | 80% | 42,090 psi | 66% | 2418 fps | 97.3% |
| Norma 217 | <<locked>> | 96% | 32,518 psi | 51% | 2339 fps | 95.7% |
| Norma MRP | 71.9 gr | 80% | 33,895 psi | 53% | 2333 fps | 96.6% |
| Norma URP | <<locked>> | 80% | 43,047 psi | 67% | 2434 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 37,855 psi | 59% | 2405 fps | 95.3% |
| Ramshot Hunter | <<locked>> | 80% | 41,858 psi | 66% | 2431 fps | 99.3% |
| Ramshot Magnum | <<locked>> | 86% | 33,663 psi | 53% | 2297 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,326 psi | 44% | 1486 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 53,563 psi | 84% | 2549 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 51,242 psi | 80% | 2592 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 43,714 psi | 69% | 2464 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 41,974 psi | 66% | 2480 fps | 99.9% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 31,502 psi | 49% | 2310 fps | 95.5% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 43,265 psi | 68% | 2556 fps | 95.8% |
| Rottweil R 903 | <<locked>> | 80% | 50,778 psi | 80% | 2500 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 38,043 psi | 60% | 2316 fps | 95% |
| Rottweil R 905 | <<locked>> | 80% | 35,955 psi | 56% | 2316 fps | 95.8% |
| Rottweil R 907 | <<locked>> | 80% | 46,804 psi | 73% | 2448 fps | 99.1% |
| Shooters World Long Rifle | <<locked>> | 80% | 45,788 psi | 72% | 2428 fps | 99.8% |
| Shooters World SW4350 | <<locked>> | 80% | 44,005 psi | 69% | 2418 fps | 99.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 52,011 psi | 82% | 2549 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 51,039 psi | 80% | 2392 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,715 psi | 70% | 2379 fps | 99.2% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,621 psi | 56% | 2310 fps | 95.7% |
| Somchem S355 | <<locked>> | 80% | 50,749 psi | 80% | 2497 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 41,321 psi | 65% | 2352 fps | 95.2% |
| Somchem S365 | <<locked>> | 80% | 39,914 psi | 63% | 2395 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,463 psi | 57% | 2300 fps | 96.9% |
| Vihtavuori N150 | <<locked>> | 80% | 48,457 psi | 76% | 2428 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,541 psi | 70% | 2431 fps | 100% |
| Vihtavuori N165 | <<locked>> | 82% | 33,678 psi | 53% | 2238 fps | 95.5% |
| Vihtavuori N550 | <<locked>> | 80% | 43,918 psi | 69% | 2434 fps | 99.9% |
| Vihtavuori N555 | <<locked>> | 80% | 35,012 psi | 55% | 2313 fps | 99.5% |
| Vihtavuori N560 | 77.3 gr | 86% | 42,076 psi | 66% | 2490 fps | 95.8% |
| Vihtavuori N565 | <<locked>> | 90% | 39,117 psi | 61% | 2421 fps | 95.2% |
| Vihtavuori N568 | <<locked>> | 98% | 44,730 psi | 70% | 2569 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,453 psi | 68% | 2395 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 45,527 psi | 71% | 2490 fps | 99.3% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,688 psi | 43% | 2257 fps | 99.7% |
| Winchester Supreme 780 | <<locked>> | 82% | 35,578 psi | 56% | 2280 fps | 95.5% |
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 80 powders for .338 Rem. Ultra Mag. loaded with the .338 | 250gr | Sierra MatchKing. Alliant Reloder-26 delivers the highest muzzle velocity at 2,749 fps; across all powders the maximum-charge window runs from 1,624 fps to 2,749 fps. ADI AR 2217 gives the best case fill at 100 %, and 80 of the 80 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. Vihtavuori N560, Norma MRP, Accurate MAGPRO rank at the top here: for .338 Rem. Ultra Mag. with the .338 | 250gr | Sierra MatchKing 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.