Load Specifications
Load data in caliber .338 Rem. Ultra Mag. with .338 | 225gr | Barnes TAC-TX BT bullet and 96 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, Accurate High Country and Norma MRP.
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 2495 | <<locked>> | 82% | 56,173 psi | 88% | 2615 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 57,740 psi | 90% | 2694 fps | 99.5% |
| Accurate 3100ᴾ | <<locked>> | 100% | 56,275 psi | 88% | 2736 fps | 100% |
| Accurate 4064 | <<locked>> | 84% | 56,565 psi | 89% | 2667 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 54,273 psi | 85% | 2730 fps | 100% |
| Accurate High Country | <<locked>> | 96% | 53,809 psi | 84% | 2825 fps | 98.1% |
| Accurate MAGPRO | <<locked>> | 98% | 54,795 psi | 86% | 2822 fps | 97.1% |
| ADI AR 2208 | <<locked>> | 86% | 56,913 psi | 89% | 2707 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 55,637 psi | 87% | 2779 fps | 98.9% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 57,101 psi | 89% | 2831 fps | 98.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 36,274 psi | 57% | 2497 fps | 96.2% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 56,942 psi | 89% | 2828 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 55,869 psi | 88% | 2776 fps | 99% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 55,869 psi | 88% | 2776 fps | 99% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 55,869 psi | 88% | 2776 fps | 99% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 54,273 psi | 85% | 2680 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 54,505 psi | 85% | 2703 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 55,419 psi | 87% | 2789 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 56,840 psi | 89% | 2808 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 55,085 psi | 86% | 2769 fps | 98.9% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 56,159 psi | 88% | 2825 fps | 99.2% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 53,011 psi | 83% | 2749 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 45,905 psi | 72% | 2690 fps | 99.8% |
| Alliant Reloder-26 | <<locked>> | 98% | 57,392 psi | 90% | 2887 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 51,285 psi | 80% | 2749 fps | 98.4% |
| Bofors RP3 | <<locked>> | 84% | 55,129 psi | 86% | 2694 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 56,159 psi | 88% | 2825 fps | 99.2% |
| Bofors RP7 | <<locked>> | 88% | 54,476 psi | 85% | 2687 fps | 99.3% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 45,556 psi | 71% | 2631 fps | 96.7% |
| Hodgdon H380 | <<locked>> | 84% | 55,564 psi | 87% | 2713 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 56,652 psi | 89% | 2785 fps | 99.8% |
| Hodgdon H4350 | <<locked>> | 88% | 56,217 psi | 88% | 2743 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 98% | 57,203 psi | 90% | 2776 fps | 97.7% |
| Hodgdon H4831 SC | <<locked>> | 98% | 56,057 psi | 88% | 2759 fps | 97.5% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 55,637 psi | 87% | 2710 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 56,971 psi | 89% | 2743 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 44,875 psi | 70% | 2726 fps | 98% |
| Hodgdon Superformance | <<locked>> | 90% | 57,450 psi | 90% | 2825 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,405 psi | 57% | 1696 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 57,493 psi | 90% | 2710 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 56,434 psi | 88% | 2690 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 55,477 psi | 87% | 2677 fps | 99.6% |
| IMR 4350 | <<locked>> | 92% | 55,796 psi | 87% | 2720 fps | 99.5% |
| IMR 4451 Enduron | <<locked>> | 88% | 56,260 psi | 88% | 2713 fps | 99.7% |
| IMR 4831 | <<locked>> | 92% | 54,882 psi | 86% | 2723 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 55,956 psi | 88% | 2726 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 54,955 psi | 86% | 2710 fps | 97.4% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 54,331 psi | 85% | 2802 fps | 98% |
| Lovex S062 | <<locked>> | 84% | 56,449 psi | 88% | 2680 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 56,405 psi | 88% | 2707 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 54,273 psi | 85% | 2700 fps | 99.7% |
| Lovex S071ᴾ | <<locked>> | 100% | 46,427 psi | 73% | 2595 fps | 99.3% |
| Norma 203B | <<locked>> | 84% | 57,377 psi | 90% | 2736 fps | 100% |
| Norma 204 | <<locked>> | 92% | 56,753 psi | 89% | 2772 fps | 98.9% |
| Norma MRP | <<locked>> | 98% | 55,883 psi | 88% | 2848 fps | 99.8% |
| Norma URP | <<locked>> | 92% | 56,884 psi | 89% | 2769 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 54,781 psi | 86% | 2713 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 54,882 psi | 86% | 2818 fps | 98.4% |
| Ramshot Hunter | <<locked>> | 92% | 55,724 psi | 87% | 2772 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 49,037 psi | 77% | 2697 fps | 98.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,130 psi | 58% | 1739 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 55,477 psi | 87% | 2700 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 56,275 psi | 88% | 2799 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 54,418 psi | 85% | 2753 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 56,985 psi | 89% | 2838 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 45,063 psi | 71% | 2723 fps | 99% |
| Rottweil R 902 | <<locked>> | 82% | 54,955 psi | 86% | 2648 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 55,216 psi | 87% | 2690 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 57,261 psi | 90% | 2749 fps | 98.3% |
| Rottweil R 905 | <<locked>> | 96% | 54,128 psi | 85% | 2753 fps | 98.9% |
| Rottweil R 907 | <<locked>> | 88% | 54,476 psi | 85% | 2687 fps | 99.3% |
| Shooters World Long Rifle | <<locked>> | 90% | 56,405 psi | 88% | 2707 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 56,449 psi | 88% | 2680 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 54,273 psi | 85% | 2700 fps | 99.7% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 57,101 psi | 89% | 2749 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 56,144 psi | 88% | 2579 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 56,028 psi | 88% | 2664 fps | 99.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 57,421 psi | 90% | 2802 fps | 99.2% |
| Somchem S355 | <<locked>> | 86% | 55,158 psi | 86% | 2687 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 55,390 psi | 87% | 2690 fps | 97.3% |
| Somchem S365 | <<locked>> | 94% | 56,463 psi | 88% | 2766 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 54,665 psi | 86% | 2726 fps | 99.4% |
| Vihtavuori N135 | <<locked>> | 82% | 55,477 psi | 87% | 2605 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 55,637 psi | 87% | 2618 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 56,594 psi | 89% | 2661 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 55,245 psi | 87% | 2713 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 54,288 psi | 85% | 2707 fps | 99.1% |
| Vihtavuori N540 | <<locked>> | 84% | 57,566 psi | 90% | 2664 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 54,389 psi | 85% | 2717 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 55,347 psi | 87% | 2772 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 56,101 psi | 88% | 2841 fps | 97.9% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 47,732 psi | 75% | 2694 fps | 96.4% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 55,085 psi | 86% | 2677 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 56,869 psi | 89% | 2785 fps | 99.8% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 48,820 psi | 77% | 2818 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 55,071 psi | 86% | 2726 fps | 98.8% |
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 2495 | <<locked>> | 80% | 52,518 psi | 82% | 2572 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 50,647 psi | 79% | 2592 fps | 98.7% |
| Accurate 3100 | <<locked>> | 84% | 32,039 psi | 50% | 2320 fps | 95.7% |
| Accurate 4064 | <<locked>> | 80% | 49,806 psi | 78% | 2579 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 38,218 psi | 60% | 2467 fps | 99% |
| Accurate High Country | 80.3 gr | 90% | 43,453 psi | 68% | 2648 fps | 95.6% |
| Accurate MAGPRO | <<locked>> | 94% | 47,398 psi | 74% | 2703 fps | 95.3% |
| ADI AR 2208 | <<locked>> | 80% | 47,297 psi | 74% | 2569 fps | 100% |
| ADI AR 2209 | <<locked>> | 86% | 39,769 psi | 62% | 2507 fps | 95.4% |
| ADI AR 2213 | <<locked>> | 92% | 43,395 psi | 68% | 2602 fps | 95% |
| ADI AR 2225 | <<locked>> | 98% | 34,026 psi | 53% | 2441 fps | 95.1% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 52,750 psi | 83% | 2769 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 39,914 psi | 63% | 2507 fps | 95.5% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 39,914 psi | 63% | 2507 fps | 95.5% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 39,914 psi | 63% | 2507 fps | 95.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 47,848 psi | 75% | 2589 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 51,082 psi | 80% | 2654 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 37,260 psi | 58% | 2480 fps | 99.1% |
| Alliant Reloder-17 | <<locked>> | 80% | 42,496 psi | 67% | 2595 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 39,494 psi | 62% | 2500 fps | 95.4% |
| Alliant Reloder-22 | <<locked>> | 90% | 39,856 psi | 62% | 2546 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 27,122 psi | 43% | 2244 fps | 97.2% |
| Alliant Reloder-25 | <<locked>> | 88% | 30,908 psi | 48% | 2359 fps | 95.7% |
| Alliant Reloder-26 | 73.5 gr | 80% | 29,008 psi | 45% | 2349 fps | 95.7% |
| Bofors RP15 | <<locked>> | 92% | 39,320 psi | 62% | 2536 fps | 95.4% |
| Bofors RP3 | <<locked>> | 80% | 48,051 psi | 75% | 2595 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 39,856 psi | 62% | 2546 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 42,177 psi | 66% | 2480 fps | 97.2% |
| Hodgdon H1000 | <<locked>> | 98% | 42,540 psi | 67% | 2575 fps | 95.7% |
| Hodgdon H380 | <<locked>> | 80% | 48,573 psi | 76% | 2612 fps | 99.9% |
| Hodgdon H414 | <<locked>> | 80% | 40,379 psi | 63% | 2516 fps | 97.4% |
| Hodgdon H4350 | <<locked>> | 80% | 43,236 psi | 68% | 2533 fps | 96.8% |
| Hodgdon H4831 | <<locked>> | 92% | 46,499 psi | 73% | 2608 fps | 95.3% |
| Hodgdon H4831 SC | <<locked>> | 92% | 45,585 psi | 71% | 2592 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,664 psi | 54% | 2372 fps | 99.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 53,156 psi | 83% | 2694 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 39,320 psi | 62% | 2605 fps | 96.1% |
| Hodgdon Superformance | <<locked>> | 80% | 39,334 psi | 62% | 2523 fps | 96.8% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,079 psi | 42% | 1516 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,911 psi | 84% | 2664 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 49,734 psi | 78% | 2598 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,880 psi | 81% | 2625 fps | 99.3% |
| IMR 4350 | <<locked>> | 80% | 37,869 psi | 59% | 2415 fps | 96% |
| IMR 4451 Enduron | <<locked>> | 80% | 43,816 psi | 69% | 2513 fps | 98% |
| IMR 4831 | <<locked>> | 80% | 36,651 psi | 57% | 2421 fps | 98.7% |
| IMR 4895 | <<locked>> | 80% | 52,431 psi | 82% | 2680 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 45,368 psi | 71% | 2556 fps | 95.2% |
| IMR 7828 SSC | <<locked>> | 94% | 44,295 psi | 69% | 2631 fps | 95.5% |
| Lovex S062 | <<locked>> | 80% | 49,806 psi | 78% | 2589 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 41,104 psi | 64% | 2464 fps | 98.6% |
| Lovex S070 | <<locked>> | 80% | 39,247 psi | 62% | 2444 fps | 97.2% |
| Lovex S071 | <<locked>> | 88% | 31,125 psi | 49% | 2293 fps | 95.3% |
| Norma 203B | <<locked>> | 80% | 50,459 psi | 79% | 2641 fps | 100% |
| Norma 204 | <<locked>> | 82% | 40,132 psi | 63% | 2493 fps | 95.4% |
| Norma MRP | 74.9 gr | 84% | 33,794 psi | 53% | 2441 fps | 95% |
| Norma URP | <<locked>> | 80% | 38,000 psi | 60% | 2461 fps | 98.9% |
| Ramshot Big Game | <<locked>> | 80% | 50,952 psi | 80% | 2661 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 44,019 psi | 69% | 2638 fps | 95.8% |
| Ramshot Hunter | <<locked>> | 80% | 36,927 psi | 58% | 2451 fps | 97.3% |
| Ramshot Magnum | <<locked>> | 92% | 36,361 psi | 57% | 2461 fps | 95.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,644 psi | 43% | 1555 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 48,472 psi | 76% | 2595 fps | 99.3% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 45,208 psi | 71% | 2641 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 38,043 psi | 60% | 2484 fps | 98.8% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 36,912 psi | 58% | 2493 fps | 98.3% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 36,245 psi | 57% | 2526 fps | 96.1% |
| Rottweil R 902 | <<locked>> | 80% | 51,532 psi | 81% | 2598 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 45,150 psi | 71% | 2546 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 44,193 psi | 69% | 2543 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 86% | 38,435 psi | 60% | 2480 fps | 95.3% |
| Rottweil R 907 | <<locked>> | 80% | 42,177 psi | 66% | 2480 fps | 97.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 41,104 psi | 64% | 2464 fps | 98.6% |
| Shooters World Precision | <<locked>> | 80% | 49,806 psi | 78% | 2589 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 39,247 psi | 62% | 2444 fps | 97.2% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 46,630 psi | 73% | 2598 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 46,586 psi | 73% | 2457 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 40,161 psi | 63% | 2408 fps | 97.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 38,101 psi | 60% | 2477 fps | 95.1% |
| Somchem S355 | <<locked>> | 80% | 45,527 psi | 71% | 2546 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 48,240 psi | 76% | 2582 fps | 95.8% |
| Somchem S365 | <<locked>> | 80% | 34,476 psi | 54% | 2421 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 36,593 psi | 57% | 2415 fps | 95.6% |
| Vihtavuori N135 | <<locked>> | 80% | 52,083 psi | 82% | 2562 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 52,170 psi | 82% | 2575 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 43,453 psi | 68% | 2477 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 39,537 psi | 62% | 2461 fps | 99.1% |
| Vihtavuori N165 | <<locked>> | 90% | 38,580 psi | 60% | 2448 fps | 95.9% |
| Vihtavuori N540 | <<locked>> | 80% | 50,546 psi | 79% | 2572 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,957 psi | 61% | 2464 fps | 98.9% |
| Vihtavuori N555 | <<locked>> | 80% | 29,936 psi | 47% | 2313 fps | 97.2% |
| Vihtavuori N560 | <<locked>> | 92% | 45,469 psi | 71% | 2667 fps | 95.4% |
| Vihtavuori N565 | <<locked>> | 98% | 44,411 psi | 70% | 2635 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 38,696 psi | 61% | 2431 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 40,379 psi | 63% | 2516 fps | 97.4% |
| Winchester StaBALL HD | <<locked>> | 80% | 23,830 psi | 37% | 2215 fps | 96% |
| Winchester Supreme 780 | <<locked>> | 88% | 38,479 psi | 60% | 2448 fps | 95.1% |
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 96 powders for .338 Rem. Ultra Mag. loaded with the .338 | 225gr | Barnes TAC-TX BT. Alliant Reloder-26 delivers the highest muzzle velocity at 2,887 fps; across all powders the maximum-charge window runs from 1,696 fps to 2,887 fps. Accurate 3100 gives the best case fill at 100 %, and 96 of the 96 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 225.0 gr projectile in 0.338" calls for a 1:12.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, ADI AR 2213, 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. Alliant Reloder-26, Accurate High Country, Norma MRP rank at the top here: for .338 Rem. Ultra Mag. with the .338 | 225gr | Barnes TAC-TX BT 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.