Load Specifications
Load data in caliber 8.5 mm Messner Mag. with .338 | 300gr | Sierra HPBT LR MatchKing bullet and 74 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate MAGPRO, Ramshot Grand and Hodgdon Retumbo.
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: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 94% | 56,536 psi | 89% | 2477 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 54,447 psi | 85% | 2454 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 55,187 psi | 86% | 2582 fps | 99.5% |
| ADI AR 2209 | <<locked>> | 90% | 54,984 psi | 86% | 2513 fps | 100% |
| ADI AR 2213 | <<locked>> | 94% | 56,463 psi | 88% | 2575 fps | 99.9% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 50,531 psi | 79% | 2493 fps | 99.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 45,020 psi | 71% | 2467 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 55,434 psi | 87% | 2500 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 56,463 psi | 88% | 2510 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 54,520 psi | 85% | 2503 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 94% | 56,492 psi | 89% | 2569 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 54,288 psi | 85% | 2487 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 56,840 psi | 89% | 2589 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 54,244 psi | 85% | 2569 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 46,514 psi | 73% | 2516 fps | 96.6% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 54,215 psi | 85% | 2493 fps | 98.1% |
| Bofors RP15 | <<locked>> | 96% | 55,434 psi | 87% | 2556 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 52,968 psi | 83% | 2559 fps | 99.9% |
| Bofors RP5 | <<locked>> | 94% | 56,492 psi | 89% | 2569 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 56,594 psi | 89% | 2451 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 55,709 psi | 87% | 2566 fps | 100% |
| Hodgdon H414 | <<locked>> | 84% | 55,999 psi | 88% | 2503 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 55,085 psi | 86% | 2464 fps | 100% |
| Hodgdon H4831 | <<locked>> | 92% | 56,260 psi | 88% | 2516 fps | 99.6% |
| Hodgdon H4831 SC | <<locked>> | 92% | 55,187 psi | 86% | 2503 fps | 99.6% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 55,564 psi | 87% | 2428 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 55,796 psi | 87% | 2667 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 56,231 psi | 88% | 2543 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,376 psi | 59% | 1506 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 54,824 psi | 86% | 2448 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 54,505 psi | 85% | 2425 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 54,839 psi | 86% | 2448 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 57,305 psi | 90% | 2500 fps | 99.7% |
| IMR 7828 SSC | <<locked>> | 94% | 54,389 psi | 85% | 2559 fps | 99.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 40,683 psi | 64% | 2392 fps | 98.5% |
| Lovex S065 | <<locked>> | 84% | 55,288 psi | 87% | 2421 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 56,985 psi | 89% | 2467 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 57,667 psi | 90% | 2490 fps | 100% |
| Norma 204 | <<locked>> | 86% | 55,695 psi | 87% | 2500 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 40,785 psi | 64% | 2415 fps | 99.8% |
| Norma MRP | <<locked>> | 92% | 56,391 psi | 88% | 2589 fps | 100% |
| Norma URP | <<locked>> | 86% | 56,507 psi | 89% | 2484 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 54,926 psi | 86% | 2575 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 55,259 psi | 87% | 2497 fps | 100% |
| Ramshot Magnum | <<locked>> | 98% | 57,130 psi | 90% | 2566 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,189 psi | 60% | 1542 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 54,302 psi | 85% | 2477 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 56,434 psi | 88% | 2552 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 56,275 psi | 88% | 2664 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 51,271 psi | 80% | 2582 fps | 99.3% |
| Rottweil R 904 | <<locked>> | 90% | 56,231 psi | 88% | 2487 fps | 99.8% |
| Rottweil R 905 | <<locked>> | 92% | 57,725 psi | 90% | 2539 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 56,594 psi | 89% | 2451 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 55,288 psi | 87% | 2421 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 56,985 psi | 89% | 2467 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 54,244 psi | 85% | 2382 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 57,290 psi | 90% | 2539 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 57,653 psi | 90% | 2484 fps | 99.7% |
| Somchem S365 | <<locked>> | 88% | 57,000 psi | 89% | 2480 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 54,520 psi | 85% | 2467 fps | 100% |
| Vihtavuori N150 | <<locked>> | 82% | 55,288 psi | 87% | 2365 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 54,621 psi | 86% | 2428 fps | 100% |
| Vihtavuori N165 | <<locked>> | 96% | 57,711 psi | 90% | 2500 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 56,188 psi | 88% | 2520 fps | 96.8% |
| Vihtavuori N550 | <<locked>> | 86% | 57,305 psi | 90% | 2480 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 56,492 psi | 89% | 2507 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 56,144 psi | 88% | 2589 fps | 99.8% |
| Vihtavuori N565 | <<locked>> | 98% | 55,811 psi | 87% | 2575 fps | 99.8% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 52,417 psi | 82% | 2582 fps | 99% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 49,661 psi | 78% | 2579 fps | 97.1% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 57,435 psi | 90% | 2434 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 56,231 psi | 88% | 2507 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 96% | 55,738 psi | 87% | 2612 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 54,273 psi | 85% | 2467 fps | 100% |
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% | 35,694 psi | 56% | 2165 fps | 99.5% |
| Accurate 4350 | <<locked>> | 80% | 47,659 psi | 75% | 2362 fps | 100% |
| Accurate MAGPRO | 70.1 gr | 80% | 36,405 psi | 57% | 2267 fps | 95.7% |
| ADI AR 2209 | <<locked>> | 80% | 39,595 psi | 62% | 2270 fps | 98.6% |
| ADI AR 2213 | <<locked>> | 80% | 35,375 psi | 55% | 2218 fps | 96.3% |
| ADI AR 2217 | <<locked>> | 86% | 32,068 psi | 50% | 2146 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 82% | 25,512 psi | 40% | 2021 fps | 95.1% |
| Alliant Reloder-16 | <<locked>> | 80% | 45,716 psi | 72% | 2369 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 52,576 psi | 82% | 2461 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 39,697 psi | 62% | 2270 fps | 98.7% |
| Alliant Reloder-22 | <<locked>> | 80% | 35,520 psi | 56% | 2228 fps | 97.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 34,345 psi | 54% | 2188 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 29,776 psi | 47% | 2126 fps | 99% |
| Alliant Reloder-26 | <<locked>> | 80% | 37,420 psi | 59% | 2320 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 98% | 43,308 psi | 68% | 2457 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 86% | 42,583 psi | 67% | 2300 fps | 95.3% |
| Bofors RP15 | <<locked>> | 80% | 33,156 psi | 52% | 2175 fps | 97% |
| Bofors RP30 | <<locked>> | 84% | 31,096 psi | 49% | 2165 fps | 95.5% |
| Bofors RP5 | <<locked>> | 80% | 35,520 psi | 56% | 2228 fps | 97.9% |
| Bofors RP7 | <<locked>> | 80% | 50,082 psi | 78% | 2362 fps | 100% |
| Hodgdon H1000 | <<locked>> | 82% | 30,545 psi | 48% | 2110 fps | 95.2% |
| Hodgdon H414 | <<locked>> | 80% | 49,139 psi | 77% | 2411 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 51,605 psi | 81% | 2418 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 37,666 psi | 59% | 2221 fps | 96.5% |
| Hodgdon H4831 SC | <<locked>> | 80% | 37,072 psi | 58% | 2208 fps | 96.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 43,192 psi | 68% | 2264 fps | 100% |
| Hodgdon Retumbo | 66.3 gr | 80% | 29,153 psi | 46% | 2149 fps | 96% |
| Hodgdon Superformance | <<locked>> | 80% | 48,762 psi | 76% | 2441 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,978 psi | 44% | 1342 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 45,382 psi | 71% | 2310 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 80% | 51,329 psi | 80% | 2379 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 45,310 psi | 71% | 2316 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 39,421 psi | 62% | 2218 fps | 97.1% |
| IMR 7828 SSC | <<locked>> | 80% | 34,127 psi | 53% | 2201 fps | 96% |
| IMR 8133 Enduron | <<locked>> | 92% | 31,430 psi | 49% | 2195 fps | 95.4% |
| Lovex S065 | <<locked>> | 80% | 49,037 psi | 77% | 2339 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 47,369 psi | 74% | 2336 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 30,835 psi | 48% | 2064 fps | 98.5% |
| Norma 204 | <<locked>> | 80% | 45,629 psi | 72% | 2356 fps | 99.4% |
| Norma 217 | <<locked>> | 86% | 26,005 psi | 41% | 2067 fps | 95% |
| Norma MRP | <<locked>> | 80% | 37,217 psi | 58% | 2290 fps | 99.3% |
| Norma URP | <<locked>> | 80% | 46,688 psi | 73% | 2352 fps | 100% |
| Ramshot Grand | 68.2 gr | 80% | 33,562 psi | 53% | 2205 fps | 96.2% |
| Ramshot Hunter | <<locked>> | 80% | 45,455 psi | 71% | 2359 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 29,907 psi | 47% | 2110 fps | 96.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,587 psi | 45% | 1375 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 47,616 psi | 75% | 2385 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 45,629 psi | 72% | 2405 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 80% | 27,934 psi | 44% | 2123 fps | 96.6% |
| ReloadSwiss RS 80 | <<locked>> | 90% | 35,520 psi | 56% | 2303 fps | 95.5% |
| Rottweil R 904 | <<locked>> | 80% | 41,060 psi | 64% | 2254 fps | 98% |
| Rottweil R 905 | <<locked>> | 80% | 39,102 psi | 61% | 2257 fps | 98.7% |
| Rottweil R 907 | <<locked>> | 80% | 50,082 psi | 78% | 2362 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 49,037 psi | 77% | 2339 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 47,369 psi | 74% | 2336 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 47,805 psi | 75% | 2297 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 38,769 psi | 61% | 2254 fps | 98.6% |
| Somchem S361 | <<locked>> | 80% | 41,568 psi | 65% | 2244 fps | 97.4% |
| Somchem S365 | <<locked>> | 80% | 43,714 psi | 69% | 2310 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 39,610 psi | 62% | 2241 fps | 99.2% |
| Vihtavuori N150 | <<locked>> | 80% | 51,996 psi | 81% | 2326 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 48,022 psi | 75% | 2343 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 34,389 psi | 54% | 2136 fps | 97.9% |
| Vihtavuori N170 | <<locked>> | 96% | 49,052 psi | 77% | 2418 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 47,253 psi | 74% | 2349 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 38,479 psi | 60% | 2247 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 37,376 psi | 59% | 2280 fps | 96.7% |
| Vihtavuori N565 | <<locked>> | 82% | 32,779 psi | 51% | 2178 fps | 95.3% |
| Vihtavuori N568 | <<locked>> | 90% | 37,188 psi | 58% | 2316 fps | 95.5% |
| Vihtavuori N570 | <<locked>> | 96% | 43,163 psi | 68% | 2464 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 46,905 psi | 74% | 2306 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 49,298 psi | 77% | 2411 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 30,530 psi | 48% | 2228 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 36,158 psi | 57% | 2182 fps | 97.9% |
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 74 powders for 8.5 mm Messner Mag. loaded with the .338 | 300gr | Sierra HPBT LR MatchKing. Hodgdon Retumbo delivers the highest muzzle velocity at 2,667 fps; across all powders the maximum-charge window runs from 1,506 fps to 2,667 fps. ADI AR 2217 gives the best case fill at 100 %, and 74 of the 74 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 300.0 gr projectile in 0.338" calls for a 1:12.0 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, Ramshot Grand, Hodgdon Retumbo rank at the top here: for 8.5 mm Messner Mag. with the .338 | 300gr | Sierra HPBT LR 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.