Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 305gr | Peregrine Glider GRM bullet and 80 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 76.
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: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 90% | 59,088 psi | 85% | 2556 fps | 100% |
| Accurate 4350 | <<locked>> | 82% | 59,770 psi | 86% | 2562 fps | 100% |
| Accurate 8700ᴾ | <<locked>> | 100% | 42,076 psi | 60% | 2444 fps | 96.9% |
| Accurate MAGPRO | <<locked>> | 90% | 59,132 psi | 85% | 2690 fps | 100% |
| ADI APS 450 | <<locked>> | 82% | 61,438 psi | 88% | 1972 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 60,974 psi | 88% | 2644 fps | 100% |
| ADI AR 2213 | <<locked>> | 90% | 59,379 psi | 85% | 2667 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 61,786 psi | 89% | 2697 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 53,548 psi | 77% | 2723 fps | 99.7% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 55,999 psi | 80% | 2667 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 61,250 psi | 88% | 2612 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 88% | 60,379 psi | 87% | 2635 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 90% | 59,553 psi | 86% | 2657 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 61,235 psi | 88% | 2602 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 61,511 psi | 88% | 2677 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 62,642 psi | 90% | 2700 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 59,263 psi | 85% | 2756 fps | 99.9% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 50,082 psi | 72% | 2631 fps | 98.8% |
| Baschieri & Pellagri 109 | <<locked>> | 92% | 59,538 psi | 86% | 2638 fps | 99.8% |
| Bofors RP15 | <<locked>> | 94% | 62,526 psi | 90% | 2694 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 61,134 psi | 88% | 2710 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 59,553 psi | 86% | 2657 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 60,814 psi | 87% | 2566 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 59,190 psi | 85% | 2664 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 62,033 psi | 89% | 2612 fps | 100% |
| Hodgdon H4831 | <<locked>> | 94% | 61,888 psi | 89% | 2648 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 90% | 61,250 psi | 88% | 2641 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 61,235 psi | 88% | 2536 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 60,829 psi | 87% | 2772 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 62,613 psi | 90% | 2667 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,768 psi | 54% | 1581 fps | 100% |
| IMR 4350 | <<locked>> | 84% | 59,335 psi | 85% | 2559 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 62,192 psi | 89% | 2579 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 61,554 psi | 88% | 2572 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 62,337 psi | 90% | 2625 fps | 100% |
| IMR 7828 SSC | <<locked>> | 90% | 61,801 psi | 89% | 2703 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 60,756 psi | 87% | 2592 fps | 98% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 51,140 psi | 73% | 2605 fps | 100% |
| Lovex D100ᴾ | <<locked>> | 100% | 61,076 psi | 88% | 2644 fps | 97.3% |
| Lovex S065 | <<locked>> | 82% | 59,393 psi | 85% | 2530 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 61,598 psi | 88% | 2582 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 60,713 psi | 87% | 2575 fps | 100% |
| Norma 204 | <<locked>> | 84% | 60,829 psi | 87% | 2621 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 52,040 psi | 75% | 2621 fps | 100% |
| Norma MRP | <<locked>> | 88% | 59,741 psi | 86% | 2671 fps | 100% |
| Norma URP | <<locked>> | 84% | 61,830 psi | 89% | 2592 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 62,381 psi | 90% | 2713 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 60,669 psi | 87% | 2612 fps | 100% |
| Ramshot Magnum | <<locked>> | 90% | 58,813 psi | 84% | 2628 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,682 psi | 56% | 1617 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 60,031 psi | 86% | 2589 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 82% | 58,842 psi | 85% | 2621 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 61,888 psi | 89% | 2766 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 60,872 psi | 87% | 2753 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 61,308 psi | 88% | 2612 fps | 100% |
| Rottweil R 905 | <<locked>> | 88% | 60,075 psi | 86% | 2625 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 60,814 psi | 87% | 2566 fps | 100% |
| Shooters World 50 BMGᴾ | <<locked>> | 100% | 61,076 psi | 88% | 2644 fps | 97.3% |
| Shooters World Long Rifle | <<locked>> | 82% | 59,393 psi | 85% | 2530 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 61,598 psi | 88% | 2582 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 43,961 psi | 63% | 2454 fps | 97% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 62,047 psi | 89% | 2536 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 59,669 psi | 86% | 2621 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 62,830 psi | 90% | 2608 fps | 100% |
| Somchem S365 | <<locked>> | 84% | 59,422 psi | 85% | 2546 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 60,292 psi | 87% | 2592 fps | 100% |
| Unknown powder | <<locked>> | 82% | 61,670 psi | 89% | 2592 fps | 100% |
| Vihtavuori N150 | <<locked>> | 84% | 60,524 psi | 87% | 2477 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 62,047 psi | 89% | 2559 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 62,134 psi | 89% | 2602 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 56,623 psi | 81% | 2598 fps | 98.7% |
| Vihtavuori N550 | <<locked>> | 82% | 62,584 psi | 90% | 2605 fps | 100% |
| Vihtavuori N555 | <<locked>> | 88% | 59,350 psi | 85% | 2582 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 59,944 psi | 86% | 2697 fps | 100% |
| Vihtavuori N565 | <<locked>> | 94% | 59,611 psi | 86% | 2674 fps | 100% |
| Vihtavuori N568 | <<locked>> | 98% | 61,192 psi | 88% | 2749 fps | 100% |
| Vihtavuori N570 | <<locked>> | 98% | 59,016 psi | 85% | 2762 fps | 99.8% |
| Winchester 6.5 StaBALL | <<locked>> | 82% | 58,900 psi | 85% | 2493 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 61,873 psi | 89% | 2697 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 61,772 psi | 89% | 2612 fps | 100% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 80% | 42,264 psi | 61% | 2329 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 55,956 psi | 80% | 2520 fps | 100% |
| Accurate 8700 | <<locked>> | 98% | 39,044 psi | 56% | 2385 fps | 95.9% |
| Accurate MAGPRO | <<locked>> | 80% | 41,626 psi | 60% | 2418 fps | 98.4% |
| ADI APS 450 | <<locked>> | 80% | 59,451 psi | 85% | 1949 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 46,775 psi | 67% | 2451 fps | 100% |
| ADI AR 2213 | <<locked>> | 80% | 41,843 psi | 60% | 2411 fps | 99.5% |
| ADI AR 2217 | <<locked>> | 80% | 30,980 psi | 45% | 2188 fps | 97.2% |
| ADI AR 2218 | <<locked>> | 90% | 37,202 psi | 53% | 2411 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 80% | 28,282 psi | 41% | 2169 fps | 98.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 53,954 psi | 78% | 2526 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 46,615 psi | 67% | 2444 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 80% | 42,482 psi | 61% | 2411 fps | 99.9% |
| Alliant Reloder-23 | <<locked>> | 80% | 41,350 psi | 59% | 2346 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,679 psi | 51% | 2310 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 46,499 psi | 67% | 2500 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 86% | 35,027 psi | 50% | 2349 fps | 95.2% |
| Alliant Reloder-50 | <<locked>> | 92% | 36,912 psi | 53% | 2395 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 40,582 psi | 58% | 2339 fps | 97.1% |
| Bofors RP15 | <<locked>> | 80% | 39,508 psi | 57% | 2359 fps | 99.7% |
| Bofors RP30 | <<locked>> | 80% | 33,054 psi | 47% | 2257 fps | 98.1% |
| Bofors RP5 | <<locked>> | 80% | 42,482 psi | 61% | 2411 fps | 99.9% |
| Bofors RP7 | <<locked>> | 80% | 56,956 psi | 82% | 2516 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 31,821 psi | 46% | 2211 fps | 98.1% |
| Hodgdon H4350 | <<locked>> | 80% | 54,795 psi | 79% | 2523 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 39,291 psi | 56% | 2313 fps | 98.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 43,642 psi | 63% | 2392 fps | 99.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 50,386 psi | 72% | 2408 fps | 100% |
| Hodgdon Retumbo | 78.2 gr | 80% | 34,795 psi | 50% | 2359 fps | 99.7% |
| Hodgdon Superformance | <<locked>> | 80% | 58,160 psi | 84% | 2615 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,282 psi | 41% | 1411 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 52,446 psi | 75% | 2470 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 58,305 psi | 84% | 2533 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 48,066 psi | 69% | 2405 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 45,614 psi | 66% | 2395 fps | 99.6% |
| IMR 7828 SSC | <<locked>> | 80% | 43,337 psi | 62% | 2444 fps | 99.7% |
| IMR 7977 Enduron | <<locked>> | 88% | 46,978 psi | 67% | 2395 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 82% | 27,601 psi | 40% | 2149 fps | 95.8% |
| Lovex D100 | <<locked>> | 96% | 52,808 psi | 76% | 2536 fps | 95.7% |
| Lovex S065 | <<locked>> | 80% | 55,883 psi | 80% | 2487 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 54,273 psi | 78% | 2493 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 36,434 psi | 52% | 2231 fps | 100% |
| Norma 204 | <<locked>> | 80% | 53,200 psi | 76% | 2526 fps | 100% |
| Norma 217 | <<locked>> | 80% | 25,831 psi | 37% | 2116 fps | 97.3% |
| Norma MRP | <<locked>> | 80% | 45,150 psi | 65% | 2474 fps | 100% |
| Norma URP | <<locked>> | 80% | 54,273 psi | 78% | 2503 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 45,774 psi | 66% | 2497 fps | 100% |
| Ramshot Hunter | <<locked>> | 80% | 53,229 psi | 76% | 2520 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 39,958 psi | 57% | 2365 fps | 100% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,008 psi | 42% | 1444 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 56,159 psi | 81% | 2546 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 54,940 psi | 79% | 2575 fps | 100% |
| ReloadSwiss RS 76 | 83.7 gr | 80% | 33,779 psi | 49% | 2336 fps | 99.9% |
| ReloadSwiss RS 80 | <<locked>> | 80% | 30,647 psi | 44% | 2241 fps | 95.8% |
| Rottweil R 904 | <<locked>> | 80% | 47,558 psi | 68% | 2425 fps | 99.9% |
| Rottweil R 905 | <<locked>> | 80% | 46,137 psi | 66% | 2434 fps | 100% |
| Rottweil R 907 | <<locked>> | 80% | 56,956 psi | 82% | 2516 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 96% | 52,808 psi | 76% | 2536 fps | 95.7% |
| Shooters World Long Rifle | <<locked>> | 80% | 55,883 psi | 80% | 2487 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 54,273 psi | 78% | 2493 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 96% | 38,363 psi | 55% | 2352 fps | 95.3% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 54,520 psi | 78% | 2448 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 45,818 psi | 66% | 2431 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 48,341 psi | 69% | 2418 fps | 99.7% |
| Somchem S365 | <<locked>> | 80% | 52,156 psi | 75% | 2461 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 46,383 psi | 67% | 2408 fps | 100% |
| Unknown powder | <<locked>> | 80% | 57,914 psi | 83% | 2549 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 53,505 psi | 77% | 2395 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 58,059 psi | 83% | 2516 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,349 psi | 57% | 2287 fps | 99.8% |
| Vihtavuori N170 | <<locked>> | 90% | 41,104 psi | 59% | 2352 fps | 95.5% |
| Vihtavuori N550 | <<locked>> | 80% | 58,653 psi | 84% | 2559 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,832 psi | 66% | 2408 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 42,743 psi | 61% | 2441 fps | 99.4% |
| Vihtavuori N565 | <<locked>> | 80% | 36,985 psi | 53% | 2320 fps | 98.5% |
| Vihtavuori N568 | <<locked>> | 80% | 32,126 psi | 46% | 2257 fps | 95.7% |
| Vihtavuori N570 | 88.2 gr | 86% | 38,145 psi | 55% | 2421 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 55,042 psi | 79% | 2451 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 39,276 psi | 56% | 2408 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 46,572 psi | 67% | 2418 fps | 100% |
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 80 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 305gr | Peregrine Glider GRM. Hodgdon Retumbo delivers the highest muzzle velocity at 2,772 fps; across all powders the maximum-charge window runs from 1,581 fps to 2,772 fps. Accurate 8700 gives the best case fill at 100 %, and 80 of the 80 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (480 MPa), the top charges use 54–90 %, leaving at least 10 % headroom. The 305.0 gr projectile in 0.338" calls for a 1:9.0 twist; slower twists will usually not stabilise this weight. Accurate 8700, ADI AR 2217, ADI AR 2218 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 76 rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 305gr | Peregrine Glider GRM 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.