Load Specifications
Load data in caliber 8.5 mm Messner Mag. with .338 | 250gr | Nosler Partition bullet and 81 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.
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: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 96% | 55,230 psi | 87% | 2713 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 57,116 psi | 90% | 2746 fps | 100% |
| Accurate MAGPRO | <<locked>> | 96% | 57,464 psi | 90% | 2864 fps | 98.7% |
| ADI AR 2208 | <<locked>> | 82% | 55,027 psi | 86% | 2654 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 57,682 psi | 90% | 2802 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 96% | 55,230 psi | 87% | 2805 fps | 99.1% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 46,238 psi | 72% | 2651 fps | 97.8% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 40,973 psi | 64% | 2615 fps | 99.3% |
| Alliant Power Pro Varmint | <<locked>> | 94% | 57,725 psi | 90% | 2795 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 82% | 56,144 psi | 88% | 2674 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 88% | 54,056 psi | 85% | 2743 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 84% | 55,288 psi | 87% | 2759 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 56,971 psi | 89% | 2789 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 96% | 54,940 psi | 86% | 2802 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 98% | 56,014 psi | 88% | 2769 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 51,532 psi | 81% | 2776 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 56,289 psi | 88% | 2861 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 57,246 psi | 90% | 2766 fps | 96.9% |
| Bofors RP15ᴾ | <<locked>> | 100% | 57,667 psi | 90% | 2838 fps | 99.8% |
| Bofors RP3 | <<locked>> | 82% | 57,261 psi | 90% | 2694 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 47,572 psi | 75% | 2720 fps | 98.5% |
| Bofors RP5 | <<locked>> | 96% | 54,940 psi | 86% | 2802 fps | 99.7% |
| Bofors RP7 | <<locked>> | 86% | 56,130 psi | 88% | 2694 fps | 99.9% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 50,908 psi | 80% | 2733 fps | 99.1% |
| Hodgdon H380 | <<locked>> | 82% | 57,334 psi | 90% | 2713 fps | 100% |
| Hodgdon H414 | <<locked>> | 86% | 55,114 psi | 86% | 2746 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 54,302 psi | 85% | 2703 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 94% | 55,390 psi | 87% | 2746 fps | 98.6% |
| Hodgdon H4831 SC | <<locked>> | 94% | 54,128 psi | 85% | 2730 fps | 98.4% |
| Hodgdon Hybrid 100V | <<locked>> | 90% | 54,389 psi | 85% | 2671 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 50,618 psi | 79% | 2841 fps | 99.9% |
| Hodgdon Superformance | <<locked>> | 86% | 55,201 psi | 87% | 2782 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,941 psi | 58% | 1667 fps | 100% |
| IMR 4350 | <<locked>> | 90% | 57,508 psi | 90% | 2730 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 86% | 57,624 psi | 90% | 2717 fps | 100% |
| IMR 4831 | <<locked>> | 90% | 57,232 psi | 90% | 2733 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 56,594 psi | 89% | 2730 fps | 98.8% |
| IMR 7828 SSC | <<locked>> | 98% | 56,623 psi | 89% | 2838 fps | 99.3% |
| Lovex S065 | <<locked>> | 86% | 54,766 psi | 86% | 2664 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 56,130 psi | 88% | 2710 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 52,591 psi | 82% | 2677 fps | 100% |
| Norma 204 | <<locked>> | 88% | 54,810 psi | 86% | 2733 fps | 99.5% |
| Norma 217ᴾ | <<locked>> | 100% | 36,550 psi | 57% | 2546 fps | 97.7% |
| Norma MRP | <<locked>> | 94% | 54,665 psi | 86% | 2822 fps | 100% |
| Norma URP | <<locked>> | 88% | 55,405 psi | 87% | 2726 fps | 100% |
| Ramshot Grand | <<locked>> | 98% | 57,334 psi | 90% | 2858 fps | 99.6% |
| Ramshot Hunter | <<locked>> | 88% | 54,201 psi | 85% | 2736 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 55,492 psi | 87% | 2795 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,782 psi | 59% | 1706 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 56,927 psi | 89% | 2703 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 82% | 54,650 psi | 86% | 2743 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 56,971 psi | 89% | 2769 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 88% | 55,071 psi | 86% | 2795 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 50,865 psi | 80% | 2838 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 45,861 psi | 72% | 2726 fps | 96.7% |
| Rottweil R 903 | <<locked>> | 84% | 57,319 psi | 90% | 2687 fps | 100% |
| Rottweil R 904 | <<locked>> | 92% | 55,332 psi | 87% | 2717 fps | 99% |
| Rottweil R 905 | <<locked>> | 94% | 56,492 psi | 89% | 2776 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 86% | 56,130 psi | 88% | 2694 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 86% | 54,766 psi | 86% | 2664 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 56,130 psi | 88% | 2710 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 82% | 55,158 psi | 86% | 2697 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 57,421 psi | 90% | 2562 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 57,464 psi | 90% | 2671 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 56,072 psi | 88% | 2772 fps | 99.8% |
| Somchem S355 | <<locked>> | 84% | 56,985 psi | 89% | 2680 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 56,869 psi | 89% | 2710 fps | 98.7% |
| Somchem S365 | <<locked>> | 90% | 55,521 psi | 87% | 2726 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 56,985 psi | 89% | 2749 fps | 100% |
| Vihtavuori N150 | <<locked>> | 84% | 54,694 psi | 86% | 2608 fps | 100% |
| Vihtavuori N160 | <<locked>> | 88% | 57,377 psi | 90% | 2720 fps | 100% |
| Vihtavuori N165 | <<locked>> | 98% | 56,333 psi | 88% | 2730 fps | 99.9% |
| Vihtavuori N550 | <<locked>> | 88% | 56,289 psi | 88% | 2723 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 54,839 psi | 86% | 2746 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 54,665 psi | 86% | 2818 fps | 98.8% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 54,143 psi | 85% | 2799 fps | 98.9% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 47,166 psi | 74% | 2733 fps | 96.5% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 56,637 psi | 89% | 2677 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 55,317 psi | 87% | 2749 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 57,014 psi | 89% | 2900 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 96% | 57,043 psi | 89% | 2749 fps | 99.7% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 32,300 psi | 51% | 2303 fps | 97.4% |
| Accurate 4350 | <<locked>> | 80% | 43,497 psi | 68% | 2539 fps | 100% |
| Accurate MAGPRO | 82.2 gr | 88% | 43,410 psi | 68% | 2628 fps | 95.8% |
| ADI AR 2208 | <<locked>> | 80% | 51,764 psi | 81% | 2608 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 36,376 psi | 57% | 2421 fps | 96% |
| ADI AR 2213 | <<locked>> | 86% | 39,595 psi | 62% | 2523 fps | 95.6% |
| ADI AR 2217 | <<locked>> | 94% | 37,884 psi | 59% | 2480 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 90% | 29,849 psi | 47% | 2333 fps | 95% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 36,695 psi | 57% | 2425 fps | 96.1% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 52,823 psi | 83% | 2628 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 41,800 psi | 66% | 2546 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 48,051 psi | 75% | 2657 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 36,376 psi | 57% | 2421 fps | 96.1% |
| Alliant Reloder-22 | <<locked>> | 82% | 34,505 psi | 54% | 2418 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 31,067 psi | 49% | 2336 fps | 99.7% |
| Alliant Reloder-25 | <<locked>> | 80% | 27,137 psi | 43% | 2244 fps | 95.7% |
| Alliant Reloder-26 | <<locked>> | 80% | 33,576 psi | 53% | 2461 fps | 99.1% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 50,647 psi | 79% | 2661 fps | 95.5% |
| Bofors RP15 | <<locked>> | 84% | 34,229 psi | 54% | 2411 fps | 95.3% |
| Bofors RP3 | <<locked>> | 80% | 53,606 psi | 84% | 2644 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 36,463 psi | 57% | 2500 fps | 95.5% |
| Bofors RP5 | <<locked>> | 82% | 34,505 psi | 54% | 2418 fps | 95.6% |
| Bofors RP7 | <<locked>> | 80% | 46,528 psi | 73% | 2543 fps | 99.2% |
| Hodgdon H1000 | <<locked>> | 90% | 36,376 psi | 57% | 2451 fps | 95.3% |
| Hodgdon H380 | <<locked>> | 80% | 53,737 psi | 84% | 2664 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 45,266 psi | 71% | 2589 fps | 99.4% |
| Hodgdon H4350 | <<locked>> | 80% | 47,906 psi | 75% | 2602 fps | 99% |
| Hodgdon H4831 | <<locked>> | 86% | 42,264 psi | 66% | 2526 fps | 95.8% |
| Hodgdon H4831 SC | <<locked>> | 86% | 41,481 psi | 65% | 2510 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 39,363 psi | 62% | 2438 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 34,272 psi | 54% | 2487 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 44,440 psi | 70% | 2612 fps | 99.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,702 psi | 43% | 1490 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 42,018 psi | 66% | 2480 fps | 98.5% |
| IMR 4451 Enduron | <<locked>> | 80% | 47,993 psi | 75% | 2569 fps | 99.6% |
| IMR 4831 | <<locked>> | 80% | 41,568 psi | 65% | 2493 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 84% | 41,379 psi | 65% | 2474 fps | 95.7% |
| IMR 7828 SSC | <<locked>> | 86% | 37,971 psi | 60% | 2497 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 45,556 psi | 71% | 2520 fps | 99.9% |
| Lovex S070 | <<locked>> | 80% | 43,874 psi | 69% | 2513 fps | 99.3% |
| Lovex S071 | <<locked>> | 80% | 27,905 psi | 44% | 2192 fps | 95.6% |
| Norma 204 | <<locked>> | 80% | 41,814 psi | 66% | 2516 fps | 97.5% |
| Norma 217 | <<locked>> | 96% | 32,097 psi | 50% | 2434 fps | 95.8% |
| Norma MRP | 73.4 gr | 80% | 33,605 psi | 53% | 2428 fps | 96.7% |
| Norma URP | <<locked>> | 80% | 42,888 psi | 67% | 2530 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 37,507 psi | 59% | 2503 fps | 95.4% |
| Ramshot Hunter | <<locked>> | 80% | 41,582 psi | 65% | 2526 fps | 99.4% |
| Ramshot Magnum | <<locked>> | 86% | 33,388 psi | 52% | 2392 fps | 95.9% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,369 psi | 44% | 1526 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 53,432 psi | 84% | 2654 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 50,981 psi | 80% | 2694 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 43,352 psi | 68% | 2562 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 41,568 psi | 65% | 2575 fps | 99.9% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 31,198 psi | 49% | 2405 fps | 95.7% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 42,598 psi | 67% | 2664 fps | 95.8% |
| Rottweil R 903 | <<locked>> | 80% | 50,604 psi | 79% | 2598 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 37,797 psi | 59% | 2405 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 80% | 35,665 psi | 56% | 2405 fps | 96% |
| Rottweil R 907 | <<locked>> | 80% | 46,528 psi | 73% | 2543 fps | 99.2% |
| Shooters World Long Rifle | <<locked>> | 80% | 45,556 psi | 71% | 2520 fps | 99.9% |
| Shooters World SW4350 | <<locked>> | 80% | 43,874 psi | 69% | 2513 fps | 99.3% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 51,692 psi | 81% | 2648 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 50,865 psi | 80% | 2480 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 44,570 psi | 70% | 2470 fps | 99.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 35,346 psi | 55% | 2402 fps | 95.9% |
| Somchem S355 | <<locked>> | 80% | 50,444 psi | 79% | 2592 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 41,017 psi | 64% | 2448 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 39,566 psi | 62% | 2487 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 36,260 psi | 57% | 2392 fps | 97.1% |
| Vihtavuori N150 | <<locked>> | 80% | 48,298 psi | 76% | 2520 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 44,208 psi | 69% | 2523 fps | 100% |
| Vihtavuori N165 | <<locked>> | 82% | 33,475 psi | 52% | 2326 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 43,671 psi | 68% | 2530 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 34,751 psi | 54% | 2405 fps | 99.6% |
| Vihtavuori N560 | 77.1 gr | 84% | 38,957 psi | 61% | 2533 fps | 95.1% |
| Vihtavuori N565 | <<locked>> | 90% | 38,667 psi | 61% | 2520 fps | 95.3% |
| Vihtavuori N568 | <<locked>> | 98% | 44,077 psi | 69% | 2674 fps | 95.6% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 43,178 psi | 68% | 2487 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 45,266 psi | 71% | 2589 fps | 99.4% |
| Winchester StaBALL HD | <<locked>> | 80% | 27,485 psi | 43% | 2349 fps | 99.8% |
| Winchester Supreme 780 | <<locked>> | 82% | 35,273 psi | 55% | 2372 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 81 powders for 8.5 mm Messner Mag. loaded with the .338 | 250gr | Nosler Partition. Winchester StaBALL HD delivers the highest muzzle velocity at 2,900 fps; across all powders the maximum-charge window runs from 1,667 fps to 2,900 fps. ADI AR 2217 gives the best case fill at 100 %, and 81 of the 81 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 250.0 gr projectile in 0.338" calls for a 1:15.0 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. Vihtavuori N560, Norma MRP, Accurate MAGPRO rank at the top here: for 8.5 mm Messner Mag. with the .338 | 250gr | Nosler Partition 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.