Load Specifications
Load data in caliber .340 Weath. Mag. with .338 | 300gr | MAKER .338 ARC/Spectre Expanding Subsonic bullet and 91 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: 26"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2700 | <<locked>> | 82% | 56,275 psi | 88% | 2362 fps | 100% |
| Accurate 3100 | <<locked>> | 98% | 54,969 psi | 86% | 2418 fps | 100% |
| Accurate 4064 | <<locked>> | 82% | 56,391 psi | 88% | 2333 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 57,130 psi | 90% | 2444 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 57,116 psi | 90% | 2562 fps | 99.1% |
| ADI AR 2208 | <<locked>> | 84% | 55,796 psi | 87% | 2365 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 54,056 psi | 85% | 2454 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 98% | 55,332 psi | 87% | 2507 fps | 99.4% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 43,207 psi | 68% | 2320 fps | 97.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 38,029 psi | 60% | 2293 fps | 99.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 56,884 psi | 89% | 2382 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 56,898 psi | 89% | 2402 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 54,259 psi | 85% | 2448 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 55,463 psi | 87% | 2464 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 57,188 psi | 90% | 2490 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 98% | 54,737 psi | 86% | 2503 fps | 99.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 55,477 psi | 87% | 2467 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 48,022 psi | 75% | 2438 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 55,666 psi | 87% | 2559 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 57,653 psi | 90% | 2474 fps | 97.4% |
| Bofors RP15ᴾ | <<locked>> | 100% | 53,664 psi | 84% | 2490 fps | 99.8% |
| Bofors RP3 | <<locked>> | 84% | 57,711 psi | 90% | 2398 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 43,758 psi | 69% | 2382 fps | 98.4% |
| Bofors RP5 | <<locked>> | 98% | 54,737 psi | 86% | 2503 fps | 99.9% |
| Bofors RP7 | <<locked>> | 88% | 56,855 psi | 89% | 2402 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 47,500 psi | 74% | 2395 fps | 99% |
| Hodgdon H380 | <<locked>> | 82% | 54,302 psi | 85% | 2375 fps | 100% |
| Hodgdon H414 | <<locked>> | 88% | 55,317 psi | 87% | 2451 fps | 100% |
| Hodgdon H4350 | <<locked>> | 86% | 54,998 psi | 86% | 2415 fps | 99.9% |
| Hodgdon H4831 | <<locked>> | 96% | 55,535 psi | 87% | 2454 fps | 99% |
| Hodgdon H4831 SC | <<locked>> | 96% | 54,273 psi | 85% | 2438 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 54,665 psi | 86% | 2379 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 46,876 psi | 73% | 2487 fps | 99.8% |
| Hodgdon Superformance | <<locked>> | 88% | 55,463 psi | 87% | 2490 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,753 psi | 58% | 1444 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 55,332 psi | 87% | 2346 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 57,537 psi | 90% | 2385 fps | 100% |
| IMR 4350 | <<locked>> | 90% | 54,578 psi | 86% | 2395 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 86% | 54,984 psi | 86% | 2379 fps | 100% |
| IMR 4831 | <<locked>> | 92% | 57,319 psi | 90% | 2434 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 56,927 psi | 89% | 2438 fps | 99.2% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 56,608 psi | 89% | 2536 fps | 99.6% |
| Lovex S062 | <<locked>> | 82% | 55,579 psi | 87% | 2336 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 55,288 psi | 87% | 2375 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 56,594 psi | 89% | 2418 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 49,008 psi | 77% | 2343 fps | 100% |
| Norma 203B | <<locked>> | 82% | 56,188 psi | 88% | 2388 fps | 100% |
| Norma 204 | <<locked>> | 90% | 55,085 psi | 86% | 2444 fps | 99.8% |
| Norma 217ᴾ | <<locked>> | 100% | 33,605 psi | 53% | 2231 fps | 97.5% |
| Norma MRP | <<locked>> | 96% | 54,331 psi | 85% | 2523 fps | 100% |
| Norma URP | <<locked>> | 90% | 55,622 psi | 87% | 2431 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 57,087 psi | 89% | 2418 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 57,246 psi | 90% | 2552 fps | 99.8% |
| Ramshot Hunter | <<locked>> | 90% | 54,273 psi | 85% | 2441 fps | 100% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 51,155 psi | 80% | 2448 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,565 psi | 59% | 1480 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 57,653 psi | 90% | 2411 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 55,056 psi | 86% | 2451 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 56,884 psi | 89% | 2470 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 55,259 psi | 87% | 2500 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 46,717 psi | 73% | 2484 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 41,959 psi | 66% | 2385 fps | 96.4% |
| Rottweil R 902 | <<locked>> | 82% | 57,479 psi | 90% | 2343 fps | 100% |
| Rottweil R 903 | <<locked>> | 84% | 54,375 psi | 85% | 2356 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 55,869 psi | 88% | 2428 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 96% | 56,463 psi | 88% | 2477 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 88% | 56,855 psi | 89% | 2402 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 88% | 55,288 psi | 87% | 2375 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 55,579 psi | 87% | 2336 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 56,594 psi | 89% | 2418 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 55,883 psi | 88% | 2408 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 55,042 psi | 86% | 2244 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 54,636 psi | 86% | 2336 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 55,999 psi | 88% | 2474 fps | 99.9% |
| Somchem S355 | <<locked>> | 84% | 54,389 psi | 85% | 2352 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 57,188 psi | 90% | 2421 fps | 99% |
| Somchem S365 | <<locked>> | 92% | 55,376 psi | 87% | 2431 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 57,043 psi | 89% | 2454 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 55,535 psi | 87% | 2326 fps | 100% |
| Vihtavuori N160 | <<locked>> | 90% | 57,653 psi | 90% | 2421 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 56,188 psi | 88% | 2434 fps | 100% |
| Vihtavuori N540 | <<locked>> | 82% | 56,086 psi | 88% | 2323 fps | 100% |
| Vihtavuori N550 | <<locked>> | 90% | 56,579 psi | 89% | 2431 fps | 100% |
| Vihtavuori N555 | <<locked>> | 96% | 54,491 psi | 85% | 2451 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 54,505 psi | 85% | 2523 fps | 99.1% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 49,922 psi | 78% | 2451 fps | 98.7% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 43,511 psi | 68% | 2395 fps | 96.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 57,101 psi | 89% | 2392 fps | 100% |
| Winchester 760 | <<locked>> | 88% | 55,564 psi | 87% | 2454 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 51,242 psi | 80% | 2543 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 98% | 57,043 psi | 89% | 2454 fps | 99.9% |
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 2700 | <<locked>> | 80% | 52,765 psi | 83% | 2316 fps | 99.9% |
| Accurate 3100 | <<locked>> | 80% | 30,269 psi | 47% | 2024 fps | 97.6% |
| Accurate 4064 | <<locked>> | 80% | 52,794 psi | 83% | 2290 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 40,930 psi | 64% | 2228 fps | 100% |
| Accurate MAGPRO | 67.6 gr | 88% | 40,350 psi | 63% | 2306 fps | 95.8% |
| ADI AR 2208 | <<locked>> | 80% | 49,443 psi | 77% | 2283 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 34,519 psi | 54% | 2126 fps | 96.2% |
| ADI AR 2213 | <<locked>> | 86% | 37,304 psi | 58% | 2211 fps | 95.7% |
| ADI AR 2217 | <<locked>> | 94% | 35,636 psi | 56% | 2175 fps | 95.2% |
| ADI AR 2225 | <<locked>> | 90% | 28,079 psi | 44% | 2051 fps | 95.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 50,386 psi | 79% | 2303 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 53,577 psi | 84% | 2362 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 39,552 psi | 62% | 2234 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 44,962 psi | 70% | 2329 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 34,389 psi | 54% | 2126 fps | 96.3% |
| Alliant Reloder-22 | <<locked>> | 82% | 32,401 psi | 51% | 2126 fps | 95.8% |
| Alliant Reloder-23 | <<locked>> | 80% | 29,153 psi | 46% | 2051 fps | 99.8% |
| Alliant Reloder-25 | <<locked>> | 80% | 25,657 psi | 40% | 1975 fps | 96% |
| Alliant Reloder-26 | <<locked>> | 80% | 31,154 psi | 49% | 2159 fps | 99.1% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 48,022 psi | 75% | 2336 fps | 95.4% |
| Bofors RP15 | <<locked>> | 84% | 32,140 psi | 50% | 2116 fps | 95.5% |
| Bofors RP3 | <<locked>> | 80% | 50,778 psi | 80% | 2316 fps | 100% |
| Bofors RP30 | <<locked>> | 92% | 33,910 psi | 53% | 2195 fps | 95.5% |
| Bofors RP5 | <<locked>> | 82% | 32,401 psi | 51% | 2126 fps | 95.8% |
| Bofors RP7 | <<locked>> | 80% | 44,411 psi | 70% | 2228 fps | 99.3% |
| Hodgdon H1000 | <<locked>> | 90% | 34,214 psi | 54% | 2149 fps | 95.4% |
| Hodgdon H380 | <<locked>> | 80% | 51,082 psi | 80% | 2333 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 42,670 psi | 67% | 2267 fps | 99.5% |
| Hodgdon H4350 | <<locked>> | 80% | 45,469 psi | 71% | 2277 fps | 99.1% |
| Hodgdon H4831 | <<locked>> | 84% | 37,217 psi | 58% | 2165 fps | 95% |
| Hodgdon H4831 SC | <<locked>> | 86% | 39,102 psi | 61% | 2201 fps | 95.7% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 37,173 psi | 58% | 2136 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 86% | 30,240 psi | 47% | 2133 fps | 95% |
| Hodgdon Superformance | <<locked>> | 80% | 41,539 psi | 65% | 2290 fps | 99.2% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,630 psi | 43% | 1289 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 52,054 psi | 82% | 2306 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 54,186 psi | 85% | 2343 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 40,045 psi | 63% | 2175 fps | 98.6% |
| IMR 4451 Enduron | <<locked>> | 80% | 45,803 psi | 72% | 2251 fps | 99.6% |
| IMR 4831 | <<locked>> | 80% | 39,160 psi | 61% | 2185 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 82% | 36,912 psi | 58% | 2123 fps | 95.1% |
| IMR 7828 SSC | <<locked>> | 86% | 35,766 psi | 56% | 2192 fps | 95.3% |
| Lovex S062 | <<locked>> | 80% | 52,315 psi | 82% | 2300 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 43,308 psi | 68% | 2208 fps | 99.9% |
| Lovex S070 | <<locked>> | 80% | 41,684 psi | 65% | 2201 fps | 99.4% |
| Lovex S071 | <<locked>> | 80% | 26,208 psi | 41% | 1929 fps | 95.9% |
| Norma 203B | <<locked>> | 80% | 52,895 psi | 83% | 2349 fps | 100% |
| Norma 204 | <<locked>> | 80% | 39,566 psi | 62% | 2208 fps | 97.6% |
| Norma 217 | <<locked>> | 96% | 29,747 psi | 47% | 2136 fps | 95.8% |
| Norma MRP | 60.3 gr | 80% | 31,430 psi | 49% | 2133 fps | 96.9% |
| Norma URP | <<locked>> | 80% | 40,524 psi | 64% | 2218 fps | 100% |
| Ramshot Big Game | <<locked>> | 80% | 53,534 psi | 84% | 2375 fps | 100% |
| Ramshot Grand | <<locked>> | 86% | 35,172 psi | 55% | 2195 fps | 95.5% |
| Ramshot Hunter | <<locked>> | 80% | 39,247 psi | 62% | 2218 fps | 99.5% |
| Ramshot Magnum | <<locked>> | 84% | 29,153 psi | 46% | 2047 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,253 psi | 44% | 1322 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 50,763 psi | 80% | 2323 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 47,732 psi | 75% | 2362 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 40,727 psi | 64% | 2247 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 39,160 psi | 61% | 2260 fps | 99.9% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 29,124 psi | 46% | 2110 fps | 95.7% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 39,015 psi | 61% | 2329 fps | 95.4% |
| Rottweil R 902 | <<locked>> | 80% | 54,114 psi | 85% | 2303 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 48,022 psi | 75% | 2274 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 35,955 psi | 56% | 2110 fps | 95.5% |
| Rottweil R 905 | <<locked>> | 80% | 33,620 psi | 53% | 2113 fps | 96.3% |
| Rottweil R 907 | <<locked>> | 80% | 44,411 psi | 70% | 2228 fps | 99.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 43,308 psi | 68% | 2208 fps | 99.9% |
| Shooters World Precision | <<locked>> | 80% | 52,315 psi | 82% | 2300 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 41,684 psi | 65% | 2201 fps | 99.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 49,066 psi | 77% | 2323 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 48,834 psi | 77% | 2172 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 42,337 psi | 66% | 2165 fps | 99.3% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 33,301 psi | 52% | 2106 fps | 96.1% |
| Somchem S355 | <<locked>> | 80% | 47,950 psi | 75% | 2270 fps | 100% |
| Somchem S361 | <<locked>> | 82% | 38,754 psi | 61% | 2146 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 37,144 psi | 58% | 2182 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 34,113 psi | 53% | 2096 fps | 97.2% |
| Vihtavuori N150 | <<locked>> | 80% | 45,963 psi | 72% | 2208 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 41,858 psi | 66% | 2211 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 29,515 psi | 46% | 1995 fps | 95% |
| Vihtavuori N540 | <<locked>> | 80% | 52,866 psi | 83% | 2283 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 41,307 psi | 65% | 2221 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 32,605 psi | 51% | 2113 fps | 99.7% |
| Vihtavuori N560 | 63.3 gr | 84% | 36,419 psi | 57% | 2221 fps | 95.1% |
| Vihtavuori N565 | <<locked>> | 90% | 35,795 psi | 56% | 2211 fps | 95.3% |
| Vihtavuori N568 | <<locked>> | 98% | 40,712 psi | 64% | 2343 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 40,698 psi | 64% | 2182 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 42,859 psi | 67% | 2270 fps | 99.5% |
| Winchester StaBALL HD | <<locked>> | 80% | 25,817 psi | 40% | 2067 fps | 99.8% |
| Winchester Supreme 780 | <<locked>> | 82% | 33,199 psi | 52% | 2080 fps | 95.8% |
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 91 powders for .340 Weath. Mag. loaded with the .338 | 300gr | MAKER .338 ARC/Spectre Expanding Subsonic. Accurate MAGPRO delivers the highest muzzle velocity at 2,562 fps; across all powders the maximum-charge window runs from 1,444 fps to 2,562 fps. ADI AR 2217 gives the best case fill at 100 %, and 91 of the 91 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 53–90 %, leaving at least 10 % headroom. The 300.0 gr projectile in 0.338" calls for a 1:11.5 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. Vihtavuori N560, Norma MRP, Accurate MAGPRO rank at the top here: for .340 Weath. Mag. with the .338 | 300gr | MAKER .338 ARC/Spectre Expanding Subsonic 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.