Load Specifications
Load data in caliber 8.5 mm Messner Mag. with .338 | 265gr | Barnes TAC-TX BT bullet and 93 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Accurate High Country, Vihtavuori N560 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.
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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 2700 | <<locked>> | 82% | 55,579 psi | 87% | 2546 fps | 99.8% |
| Accurate 3100 | <<locked>> | 98% | 54,157 psi | 85% | 2602 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 55,114 psi | 86% | 2516 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 56,304 psi | 88% | 2635 fps | 100% |
| Accurate High Country | <<locked>> | 96% | 55,622 psi | 87% | 2749 fps | 99.3% |
| Accurate MAGPRO | <<locked>> | 98% | 56,536 psi | 89% | 2749 fps | 98.6% |
| ADI AR 2208 | <<locked>> | 84% | 55,172 psi | 86% | 2552 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 57,392 psi | 90% | 2694 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 98% | 54,752 psi | 86% | 2697 fps | 99% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 42,540 psi | 67% | 2487 fps | 96.9% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 37,420 psi | 59% | 2451 fps | 98.5% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 57,450 psi | 90% | 2690 fps | 99.8% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 56,144 psi | 88% | 2572 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 56,304 psi | 88% | 2595 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 57,421 psi | 90% | 2687 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 54,926 psi | 86% | 2657 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 56,666 psi | 89% | 2680 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 98% | 54,056 psi | 85% | 2690 fps | 99.7% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 55,027 psi | 86% | 2661 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 47,471 psi | 74% | 2618 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 55,216 psi | 87% | 2749 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 57,246 psi | 90% | 2661 fps | 96.9% |
| Bofors RP15ᴾ | <<locked>> | 100% | 53,011 psi | 83% | 2674 fps | 99.5% |
| Bofors RP3 | <<locked>> | 84% | 56,884 psi | 89% | 2589 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 43,192 psi | 68% | 2552 fps | 97.7% |
| Bofors RP5 | <<locked>> | 98% | 54,056 psi | 85% | 2690 fps | 99.7% |
| Bofors RP7 | <<locked>> | 88% | 56,202 psi | 88% | 2592 fps | 99.9% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 46,949 psi | 74% | 2569 fps | 98.5% |
| Hodgdon H380 | <<locked>> | 84% | 57,348 psi | 90% | 2612 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 54,737 psi | 86% | 2641 fps | 100% |
| Hodgdon H4350 | <<locked>> | 86% | 54,346 psi | 85% | 2602 fps | 99.7% |
| Hodgdon H4831 | <<locked>> | 96% | 54,940 psi | 86% | 2641 fps | 98.5% |
| Hodgdon H4831 SC | <<locked>> | 98% | 57,537 psi | 90% | 2674 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 57,508 psi | 90% | 2608 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 46,369 psi | 73% | 2667 fps | 99.5% |
| Hodgdon Superformance | <<locked>> | 88% | 54,853 psi | 86% | 2677 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,738 psi | 58% | 1581 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 54,752 psi | 86% | 2536 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 56,971 psi | 89% | 2575 fps | 100% |
| IMR 4350 | <<locked>> | 92% | 57,479 psi | 90% | 2628 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 86% | 54,505 psi | 85% | 2569 fps | 100% |
| IMR 4831 | <<locked>> | 92% | 56,666 psi | 89% | 2628 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 56,507 psi | 89% | 2628 fps | 98.8% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 56,014 psi | 88% | 2726 fps | 99.3% |
| Lovex S062 | <<locked>> | 82% | 54,810 psi | 86% | 2526 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 54,621 psi | 86% | 2562 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 55,869 psi | 88% | 2605 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 48,037 psi | 75% | 2516 fps | 100% |
| Norma 203B | <<locked>> | 82% | 55,593 psi | 87% | 2582 fps | 100% |
| Norma 204 | <<locked>> | 90% | 54,578 psi | 86% | 2631 fps | 99.5% |
| Norma 217ᴾ | <<locked>> | 100% | 32,909 psi | 52% | 2379 fps | 96.4% |
| Norma MRP | <<locked>> | 98% | 57,711 psi | 90% | 2766 fps | 100% |
| Norma URP | <<locked>> | 90% | 55,013 psi | 86% | 2621 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 56,550 psi | 89% | 2612 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 56,855 psi | 89% | 2746 fps | 99.5% |
| Ramshot Hunter | <<locked>> | 92% | 57,479 psi | 90% | 2680 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 50,488 psi | 79% | 2628 fps | 99.7% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,420 psi | 59% | 1617 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 57,101 psi | 89% | 2602 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 54,375 psi | 85% | 2644 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 56,188 psi | 88% | 2661 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 54,708 psi | 86% | 2690 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 46,354 psi | 73% | 2664 fps | 99.9% |
| Rottweil R 902 | <<locked>> | 82% | 56,579 psi | 89% | 2533 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 56,985 psi | 89% | 2585 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 55,187 psi | 86% | 2612 fps | 99% |
| Rottweil R 905 | <<locked>> | 96% | 55,970 psi | 88% | 2671 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 88% | 56,202 psi | 88% | 2592 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 88% | 54,621 psi | 86% | 2562 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 54,810 psi | 86% | 2526 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 55,869 psi | 88% | 2605 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 55,216 psi | 87% | 2598 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 54,273 psi | 85% | 2425 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 57,696 psi | 90% | 2569 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 55,506 psi | 87% | 2664 fps | 99.7% |
| Somchem S355 | <<locked>> | 86% | 56,927 psi | 89% | 2582 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 56,826 psi | 89% | 2612 fps | 98.7% |
| Somchem S365 | <<locked>> | 92% | 54,723 psi | 86% | 2621 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 56,391 psi | 88% | 2644 fps | 100% |
| Vihtavuori N135 | <<locked>> | 82% | 57,276 psi | 90% | 2487 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 57,479 psi | 90% | 2507 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 54,607 psi | 86% | 2510 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 57,101 psi | 89% | 2615 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 55,869 psi | 88% | 2625 fps | 99.9% |
| Vihtavuori N540 | <<locked>> | 82% | 55,434 psi | 87% | 2507 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 56,130 psi | 88% | 2621 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 57,392 psi | 90% | 2684 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 53,882 psi | 84% | 2707 fps | 98.7% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 49,414 psi | 77% | 2631 fps | 98.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 56,710 psi | 89% | 2582 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 54,955 psi | 86% | 2644 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 50,908 psi | 80% | 2736 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 56,666 psi | 89% | 2644 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 2700 | <<locked>> | 80% | 52,170 psi | 82% | 2500 fps | 99.6% |
| Accurate 3100 | <<locked>> | 80% | 29,138 psi | 46% | 2159 fps | 96.4% |
| Accurate 4064 | <<locked>> | 80% | 51,648 psi | 81% | 2474 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 39,871 psi | 62% | 2388 fps | 99.9% |
| Accurate High Country | 70.1 gr | 84% | 36,448 psi | 57% | 2411 fps | 95.2% |
| Accurate MAGPRO | <<locked>> | 90% | 42,482 psi | 67% | 2523 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 80% | 48,776 psi | 76% | 2464 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 33,707 psi | 53% | 2277 fps | 95.1% |
| ADI AR 2213 | <<locked>> | 88% | 39,262 psi | 62% | 2425 fps | 95.6% |
| ADI AR 2217 | <<locked>> | 96% | 37,362 psi | 59% | 2382 fps | 95% |
| ADI AR 2225 | <<locked>> | 94% | 30,922 psi | 48% | 2287 fps | 95.8% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 33,953 psi | 53% | 2280 fps | 95.3% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 49,588 psi | 78% | 2487 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 52,794 psi | 83% | 2549 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 38,754 psi | 61% | 2402 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 44,237 psi | 69% | 2507 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 33,649 psi | 53% | 2277 fps | 95.2% |
| Alliant Reloder-22 | <<locked>> | 84% | 33,707 psi | 53% | 2323 fps | 95.5% |
| Alliant Reloder-23 | <<locked>> | 80% | 28,326 psi | 44% | 2192 fps | 99.2% |
| Alliant Reloder-25 | <<locked>> | 82% | 26,411 psi | 41% | 2152 fps | 95.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 30,327 psi | 48% | 2303 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 50,749 psi | 80% | 2562 fps | 95.4% |
| Bofors RP15 | <<locked>> | 86% | 33,417 psi | 52% | 2313 fps | 95.1% |
| Bofors RP3 | <<locked>> | 80% | 49,908 psi | 78% | 2497 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 35,331 psi | 55% | 2395 fps | 95.2% |
| Bofors RP5 | <<locked>> | 84% | 33,707 psi | 53% | 2323 fps | 95.5% |
| Bofors RP7 | <<locked>> | 80% | 43,627 psi | 68% | 2398 fps | 98.8% |
| Hodgdon H1000 | <<locked>> | 92% | 35,766 psi | 56% | 2349 fps | 95.2% |
| Hodgdon H380 | <<locked>> | 80% | 50,198 psi | 79% | 2516 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 41,989 psi | 66% | 2438 fps | 99% |
| Hodgdon H4350 | <<locked>> | 80% | 44,860 psi | 70% | 2451 fps | 98.6% |
| Hodgdon H4831 | <<locked>> | 86% | 39,189 psi | 61% | 2379 fps | 95% |
| Hodgdon H4831 SC | <<locked>> | 88% | 41,176 psi | 65% | 2415 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 36,318 psi | 57% | 2297 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 33,460 psi | 52% | 2382 fps | 95.7% |
| Hodgdon Superformance | <<locked>> | 80% | 40,901 psi | 64% | 2457 fps | 98.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,441 psi | 43% | 1411 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 51,300 psi | 80% | 2490 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 53,490 psi | 84% | 2526 fps | 99.9% |
| IMR 4350 | <<locked>> | 80% | 39,218 psi | 61% | 2339 fps | 98% |
| IMR 4451 Enduron | <<locked>> | 80% | 45,107 psi | 71% | 2421 fps | 99.3% |
| IMR 4831 | <<locked>> | 80% | 38,319 psi | 60% | 2346 fps | 99.8% |
| IMR 4955 Enduron | <<locked>> | 86% | 41,191 psi | 65% | 2379 fps | 95.8% |
| IMR 7828 SSC | <<locked>> | 88% | 37,463 psi | 59% | 2402 fps | 95.1% |
| Lovex S062 | <<locked>> | 80% | 51,634 psi | 81% | 2484 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 42,540 psi | 67% | 2379 fps | 99.7% |
| Lovex S070 | <<locked>> | 80% | 40,756 psi | 64% | 2365 fps | 98.9% |
| Lovex S071 | <<locked>> | 82% | 26,701 psi | 42% | 2096 fps | 95.3% |
| Norma 203B | <<locked>> | 80% | 52,156 psi | 82% | 2536 fps | 100% |
| Norma 204 | <<locked>> | 80% | 38,856 psi | 61% | 2369 fps | 96.8% |
| Norma 217 | <<locked>> | 98% | 30,806 psi | 48% | 2323 fps | 95.4% |
| Norma MRP | 66.8 gr | 80% | 30,632 psi | 48% | 2274 fps | 95.7% |
| Norma URP | <<locked>> | 80% | 39,653 psi | 62% | 2385 fps | 99.9% |
| Ramshot Big Game | <<locked>> | 80% | 52,852 psi | 83% | 2562 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 36,825 psi | 58% | 2402 fps | 95.3% |
| Ramshot Hunter | <<locked>> | 80% | 38,479 psi | 60% | 2379 fps | 99% |
| Ramshot Magnum | <<locked>> | 88% | 32,590 psi | 51% | 2293 fps | 95.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,949 psi | 44% | 1444 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 50,183 psi | 79% | 2507 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 47,036 psi | 74% | 2546 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 39,827 psi | 62% | 2411 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 38,435 psi | 60% | 2428 fps | 99.7% |
| ReloadSwiss RS 76 | <<locked>> | 88% | 30,342 psi | 48% | 2303 fps | 95.4% |
| Rottweil R 902 | <<locked>> | 80% | 53,258 psi | 83% | 2490 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 46,963 psi | 74% | 2451 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 37,608 psi | 59% | 2316 fps | 95.3% |
| Rottweil R 905 | <<locked>> | 80% | 32,692 psi | 51% | 2257 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 43,627 psi | 68% | 2398 fps | 98.8% |
| Shooters World Long Rifle | <<locked>> | 80% | 42,540 psi | 67% | 2379 fps | 99.7% |
| Shooters World Precision | <<locked>> | 80% | 51,634 psi | 81% | 2484 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 40,756 psi | 64% | 2365 fps | 98.9% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 48,385 psi | 76% | 2507 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 48,022 psi | 75% | 2346 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 41,510 psi | 65% | 2329 fps | 98.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 34,693 psi | 54% | 2306 fps | 95.9% |
| Somchem S355 | <<locked>> | 80% | 47,166 psi | 74% | 2448 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 40,727 psi | 64% | 2356 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 36,129 psi | 57% | 2343 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 33,228 psi | 52% | 2244 fps | 96.2% |
| Vihtavuori N135 | <<locked>> | 80% | 53,824 psi | 84% | 2448 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 53,954 psi | 85% | 2464 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 45,092 psi | 71% | 2382 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 41,089 psi | 64% | 2379 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 84% | 32,764 psi | 51% | 2231 fps | 95.6% |
| Vihtavuori N540 | <<locked>> | 80% | 52,069 psi | 82% | 2467 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 40,408 psi | 63% | 2382 fps | 99.8% |
| Vihtavuori N555 | <<locked>> | 80% | 31,459 psi | 49% | 2254 fps | 99.1% |
| Vihtavuori N560 | 71.8 gr | 86% | 38,261 psi | 60% | 2431 fps | 95% |
| Vihtavuori N565 | <<locked>> | 92% | 37,420 psi | 59% | 2415 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 40,103 psi | 63% | 2352 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 41,989 psi | 66% | 2438 fps | 99% |
| Winchester StaBALL HD | <<locked>> | 80% | 24,903 psi | 39% | 2188 fps | 99.1% |
| Winchester Supreme 780 | <<locked>> | 84% | 34,722 psi | 54% | 2280 fps | 95.6% |
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 93 powders for 8.5 mm Messner Mag. loaded with the .338 | 265gr | Barnes TAC-TX BT. Norma MRP delivers the highest muzzle velocity at 2,766 fps; across all powders the maximum-charge window runs from 1,581 fps to 2,766 fps. ADI AR 2217 gives the best case fill at 100 %, and 93 of the 93 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 52–90 %, leaving at least 10 % headroom. The 265.0 gr projectile in 0.338" calls for a 1:10.5 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Alliant Reloder-23 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 High Country, Vihtavuori N560, Norma MRP rank at the top here: for 8.5 mm Messner Mag. with the .338 | 265gr | 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.