Load Specifications
Load data in caliber .338-378 Weath. Mag. with .338 | 270gr | AERO SOLR,- smax:19.50 bullet and 67 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, Vihtavuori N570 and ReloadSwiss RS 80.
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: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 90% | 57,159 psi | 90% | 2697 fps | 100% |
| Accurate High Country | <<locked>> | 86% | 55,332 psi | 87% | 2802 fps | 100% |
| Accurate MAGPRO | <<locked>> | 88% | 56,231 psi | 88% | 2812 fps | 99.8% |
| ADI AR 2209 | <<locked>> | 86% | 55,216 psi | 87% | 2733 fps | 100% |
| ADI AR 2213 | <<locked>> | 90% | 57,246 psi | 90% | 2805 fps | 100% |
| ADI AR 2217 | <<locked>> | 98% | 55,579 psi | 87% | 2782 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 51,605 psi | 81% | 2835 fps | 98.5% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 53,693 psi | 84% | 2799 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 55,390 psi | 87% | 2733 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 55,390 psi | 87% | 2733 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 82% | 55,637 psi | 87% | 2717 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 54,795 psi | 86% | 2723 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 90% | 57,450 psi | 90% | 2799 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 90% | 55,550 psi | 87% | 2703 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 94% | 55,535 psi | 87% | 2776 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 86% | 55,985 psi | 88% | 2792 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 56,797 psi | 89% | 2877 fps | 99.1% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 47,863 psi | 75% | 2733 fps | 97.2% |
| Baschieri & Pellagri 109 | <<locked>> | 90% | 54,230 psi | 85% | 2717 fps | 98.8% |
| Bofors RP15 | <<locked>> | 92% | 56,623 psi | 89% | 2785 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 55,071 psi | 86% | 2792 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 57,450 psi | 90% | 2799 fps | 100% |
| Hodgdon H1000 | <<locked>> | 96% | 57,203 psi | 90% | 2802 fps | 100% |
| Hodgdon H4831 | <<locked>> | 88% | 56,478 psi | 89% | 2740 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 88% | 55,434 psi | 87% | 2726 fps | 99.8% |
| Hodgdon Hybrid 100V | <<locked>> | 84% | 55,695 psi | 87% | 2638 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 94% | 54,404 psi | 85% | 2861 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,608 psi | 59% | 1699 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 57,638 psi | 90% | 2703 fps | 100% |
| IMR 4831 | <<locked>> | 82% | 54,621 psi | 86% | 2654 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 88% | 57,000 psi | 89% | 2720 fps | 99.9% |
| IMR 7828 SSC | <<locked>> | 90% | 55,506 psi | 87% | 2789 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 94% | 55,405 psi | 87% | 2667 fps | 95.9% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,124 psi | 77% | 2726 fps | 99.9% |
| Lovex S070 | <<locked>> | 82% | 56,217 psi | 88% | 2680 fps | 100% |
| Lovex S071 | <<locked>> | 94% | 54,998 psi | 86% | 2671 fps | 100% |
| Norma 204 | <<locked>> | 82% | 55,158 psi | 86% | 2713 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 49,966 psi | 78% | 2746 fps | 100% |
| Norma MRP | <<locked>> | 88% | 57,566 psi | 90% | 2812 fps | 100% |
| Norma URP | <<locked>> | 82% | 56,188 psi | 88% | 2694 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 56,695 psi | 89% | 2808 fps | 100% |
| Ramshot Hunter | <<locked>> | 82% | 55,071 psi | 86% | 2707 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 54,766 psi | 86% | 2740 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,566 psi | 60% | 1739 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 56,826 psi | 89% | 2766 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 55,013 psi | 86% | 2851 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 96% | 54,114 psi | 85% | 2822 fps | 99.8% |
| Rottweil R 904 | <<locked>> | 86% | 55,869 psi | 88% | 2703 fps | 100% |
| Rottweil R 905 | <<locked>> | 86% | 54,418 psi | 85% | 2717 fps | 100% |
| Shooters World SW4350 | <<locked>> | 82% | 56,217 psi | 88% | 2680 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 82% | 56,681 psi | 89% | 2635 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 86% | 54,027 psi | 85% | 2713 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 57,290 psi | 90% | 2700 fps | 99.9% |
| Somchem S365 | <<locked>> | 84% | 57,406 psi | 90% | 2694 fps | 100% |
| Somchem S385 | <<locked>> | 86% | 54,737 psi | 86% | 2687 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 57,711 psi | 90% | 2680 fps | 100% |
| Vihtavuori N165 | <<locked>> | 90% | 54,621 psi | 86% | 2674 fps | 100% |
| Vihtavuori N170 | <<locked>> | 96% | 57,159 psi | 90% | 2756 fps | 97.9% |
| Vihtavuori N550 | <<locked>> | 82% | 56,884 psi | 89% | 2690 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 57,319 psi | 90% | 2726 fps | 100% |
| Vihtavuori N560 | <<locked>> | 88% | 57,101 psi | 89% | 2818 fps | 100% |
| Vihtavuori N565 | <<locked>> | 94% | 57,580 psi | 90% | 2808 fps | 100% |
| Vihtavuori N568 | <<locked>> | 96% | 54,955 psi | 86% | 2822 fps | 99.6% |
| Vihtavuori N570 | <<locked>> | 98% | 55,999 psi | 88% | 2884 fps | 98.8% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 57,261 psi | 90% | 2638 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 90% | 54,998 psi | 86% | 2792 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 54,520 psi | 85% | 2684 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 40,640 psi | 64% | 2448 fps | 100% |
| Accurate High Country | <<locked>> | 80% | 44,860 psi | 70% | 2631 fps | 99.3% |
| Accurate MAGPRO | <<locked>> | 80% | 42,264 psi | 66% | 2575 fps | 97.9% |
| ADI AR 2209 | <<locked>> | 80% | 45,179 psi | 71% | 2575 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 80% | 40,306 psi | 63% | 2523 fps | 98.4% |
| ADI AR 2217 | <<locked>> | 82% | 31,995 psi | 50% | 2336 fps | 96% |
| ADI AR 2218 | <<locked>> | 94% | 41,423 psi | 65% | 2631 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 80% | 27,180 psi | 43% | 2251 fps | 96.9% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 45,411 psi | 71% | 2575 fps | 99.7% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 45,411 psi | 71% | 2575 fps | 99.7% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,156 psi | 82% | 2667 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 44,991 psi | 71% | 2569 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 80% | 40,872 psi | 64% | 2526 fps | 99.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 39,697 psi | 62% | 2467 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,200 psi | 54% | 2415 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 44,570 psi | 70% | 2625 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 38,957 psi | 61% | 2562 fps | 95% |
| Alliant Reloder-50 | <<locked>> | 96% | 41,118 psi | 64% | 2608 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 39,479 psi | 62% | 2448 fps | 95.2% |
| Bofors RP15 | <<locked>> | 80% | 38,043 psi | 60% | 2467 fps | 98.7% |
| Bofors RP30 | <<locked>> | 80% | 31,560 psi | 49% | 2349 fps | 96.1% |
| Bofors RP5 | <<locked>> | 80% | 40,872 psi | 64% | 2526 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 80% | 32,532 psi | 51% | 2352 fps | 96.9% |
| Hodgdon H4831 | <<locked>> | 80% | 42,975 psi | 67% | 2523 fps | 98.4% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,148 psi | 66% | 2507 fps | 98.2% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,805 psi | 76% | 2549 fps | 100% |
| Hodgdon Retumbo | 84.2 gr | 80% | 33,402 psi | 52% | 2454 fps | 98.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,152 psi | 44% | 1516 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,879 psi | 80% | 2608 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 51,126 psi | 80% | 2608 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,237 psi | 69% | 2516 fps | 98.7% |
| IMR 7828 SSC | <<locked>> | 80% | 39,059 psi | 61% | 2507 fps | 98.1% |
| IMR 7977 Enduron | <<locked>> | 92% | 51,880 psi | 81% | 2612 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 86% | 30,313 psi | 48% | 2339 fps | 95.3% |
| Lovex S070 | <<locked>> | 80% | 52,721 psi | 83% | 2631 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 34,998 psi | 55% | 2336 fps | 99.6% |
| Norma 204 | <<locked>> | 80% | 51,619 psi | 81% | 2661 fps | 100% |
| Norma 217 | <<locked>> | 82% | 26,411 psi | 41% | 2247 fps | 95.7% |
| Norma MRP | <<locked>> | 80% | 43,381 psi | 68% | 2595 fps | 100% |
| Norma URP | <<locked>> | 80% | 52,591 psi | 82% | 2644 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 38,827 psi | 61% | 2513 fps | 98.5% |
| Ramshot Hunter | <<locked>> | 80% | 51,634 psi | 81% | 2657 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 34,766 psi | 54% | 2402 fps | 98.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,921 psi | 45% | 1555 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 52,953 psi | 83% | 2713 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 32,372 psi | 51% | 2428 fps | 99% |
| ReloadSwiss RS 80 | 95.4 gr | 84% | 34,098 psi | 53% | 2448 fps | 95.5% |
| Rottweil R 904 | <<locked>> | 80% | 46,137 psi | 72% | 2552 fps | 99.3% |
| Rottweil R 905 | <<locked>> | 80% | 44,556 psi | 70% | 2559 fps | 99.7% |
| Shooters World SW4350 | <<locked>> | 80% | 52,721 psi | 83% | 2631 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,098 psi | 83% | 2589 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,222 psi | 69% | 2556 fps | 99.7% |
| Somchem S361 | <<locked>> | 80% | 46,833 psi | 73% | 2543 fps | 99% |
| Somchem S365 | <<locked>> | 80% | 50,285 psi | 79% | 2602 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 44,831 psi | 70% | 2533 fps | 99.9% |
| Vihtavuori N160 | <<locked>> | 80% | 54,056 psi | 85% | 2635 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,102 psi | 61% | 2421 fps | 99.3% |
| Vihtavuori N170 | <<locked>> | 90% | 46,543 psi | 73% | 2585 fps | 95.6% |
| Vihtavuori N550 | <<locked>> | 80% | 53,359 psi | 84% | 2644 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,092 psi | 69% | 2536 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,236 psi | 68% | 2592 fps | 98.6% |
| Vihtavuori N565 | <<locked>> | 80% | 35,491 psi | 56% | 2418 fps | 96.8% |
| Vihtavuori N568 | <<locked>> | 84% | 35,534 psi | 56% | 2464 fps | 95.4% |
| Vihtavuori N570 | 98.3 gr | 90% | 41,901 psi | 66% | 2635 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,374 psi | 84% | 2592 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,376 psi | 59% | 2523 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,205 psi | 65% | 2470 fps | 99.3% |
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 67 powders for .338-378 Weath. Mag. loaded with the .338 | 270gr | AERO SOLR,- smax:19.50. Vihtavuori N570 delivers the highest muzzle velocity at 2,884 fps; across all powders the maximum-charge window runs from 1,699 fps to 2,884 fps. ADI AR 2218 gives the best case fill at 100 %, and 67 of the 67 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 59–90 %, leaving at least 10 % headroom. The 270.0 gr projectile in 0.338" calls for a 1:10.0 twist; slower twists will usually not stabilise this weight. ADI AR 2218, ADI AR 2225, Alliant Reloder-33 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. Hodgdon Retumbo, Vihtavuori N570, ReloadSwiss RS 80 rank at the top here: for .338-378 Weath. Mag. with the .338 | 270gr | AERO SOLR,- smax:19.50 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.