Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 285gr | Warner Tool Co. Flat Line bullet and 81 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Hodgdon Retumbo, ReloadSwiss RS 76 and Vihtavuori N570.
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: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 92% | 62,033 psi | 89% | 2674 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 62,990 psi | 90% | 2687 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 62,047 psi | 89% | 2812 fps | 100% |
| ADI APS 450 | <<locked>> | 82% | 61,351 psi | 88% | 2041 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 59,567 psi | 86% | 2713 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 61,844 psi | 89% | 2789 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 60,118 psi | 86% | 2766 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 52,054 psi | 75% | 2776 fps | 99.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,447 psi | 78% | 2736 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 88% | 59,727 psi | 86% | 2710 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 59,959 psi | 86% | 2687 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 62,946 psi | 90% | 2753 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 62,047 psi | 89% | 2776 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 59,988 psi | 86% | 2677 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 60,046 psi | 86% | 2753 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 60,988 psi | 88% | 2772 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 57,551 psi | 83% | 2818 fps | 99.5% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 48,675 psi | 70% | 2687 fps | 98% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 61,960 psi | 89% | 2753 fps | 99.7% |
| Bofors RP15 | <<locked>> | 94% | 61,148 psi | 88% | 2766 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 59,741 psi | 86% | 2779 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 62,047 psi | 89% | 2776 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 59,799 psi | 86% | 2638 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 61,888 psi | 89% | 2782 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 60,930 psi | 88% | 2687 fps | 100% |
| Hodgdon H4831 | <<locked>> | 94% | 60,553 psi | 87% | 2717 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 90% | 59,785 psi | 86% | 2707 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 60,089 psi | 86% | 2612 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 59,016 psi | 85% | 2844 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 61,235 psi | 88% | 2740 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,753 psi | 54% | 1637 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 62,453 psi | 90% | 2644 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 62,062 psi | 89% | 2680 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 61,017 psi | 88% | 2651 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 60,481 psi | 87% | 2648 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 61,206 psi | 88% | 2697 fps | 100% |
| IMR 7828 SSC | <<locked>> | 90% | 60,249 psi | 87% | 2772 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 59,712 psi | 86% | 2654 fps | 97.2% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,908 psi | 72% | 2671 fps | 100% |
| Lovex D100ᴾ | <<locked>> | 100% | 59,683 psi | 86% | 2703 fps | 96.3% |
| Lovex S065 | <<locked>> | 84% | 62,236 psi | 89% | 2648 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 60,684 psi | 87% | 2654 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 59,567 psi | 86% | 2648 fps | 100% |
| Norma 204 | <<locked>> | 84% | 59,785 psi | 86% | 2697 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 50,676 psi | 73% | 2687 fps | 100% |
| Norma MRP | <<locked>> | 90% | 62,395 psi | 90% | 2792 fps | 100% |
| Norma URP | <<locked>> | 84% | 60,713 psi | 87% | 2667 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 60,582 psi | 87% | 2782 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 59,640 psi | 86% | 2687 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 61,786 psi | 89% | 2749 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,667 psi | 56% | 1677 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 82% | 59,074 psi | 85% | 2667 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 61,815 psi | 89% | 2746 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 59,988 psi | 86% | 2838 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 59,030 psi | 85% | 2818 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 60,278 psi | 87% | 2684 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 62,830 psi | 90% | 2743 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 59,799 psi | 86% | 2638 fps | 100% |
| Shooters World 50 BMGᴾ | <<locked>> | 100% | 59,683 psi | 86% | 2703 fps | 96.3% |
| Shooters World Long Rifle | <<locked>> | 84% | 62,236 psi | 89% | 2648 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 60,684 psi | 87% | 2654 fps | 100% |
| SNPE Vectan SP 13ᴾ | <<locked>> | 100% | 43,178 psi | 62% | 2513 fps | 96% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 61,293 psi | 88% | 2612 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 62,395 psi | 90% | 2740 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 61,830 psi | 89% | 2680 fps | 100% |
| Somchem S365 | <<locked>> | 86% | 62,265 psi | 89% | 2667 fps | 100% |
| Somchem S385 | <<locked>> | 88% | 59,277 psi | 85% | 2667 fps | 100% |
| Unknown powder | <<locked>> | 82% | 60,582 psi | 87% | 2671 fps | 100% |
| Vihtavuori N150 | <<locked>> | 84% | 59,553 psi | 86% | 2549 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 60,901 psi | 87% | 2635 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 60,843 psi | 87% | 2674 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 55,593 psi | 80% | 2661 fps | 98% |
| Vihtavuori N550 | <<locked>> | 82% | 61,525 psi | 88% | 2684 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 61,975 psi | 89% | 2700 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 62,540 psi | 90% | 2815 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 62,410 psi | 90% | 2795 fps | 100% |
| Vihtavuori N568 | <<locked>> | 98% | 59,698 psi | 86% | 2815 fps | 100% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 61,554 psi | 88% | 2881 fps | 99.7% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 61,844 psi | 89% | 2612 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 59,930 psi | 86% | 2772 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 60,466 psi | 87% | 2684 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% | 41,756 psi | 60% | 2398 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 55,056 psi | 79% | 2592 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 40,872 psi | 59% | 2480 fps | 97.6% |
| ADI APS 450 | <<locked>> | 80% | 59,408 psi | 85% | 2014 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 45,832 psi | 66% | 2516 fps | 99.9% |
| ADI AR 2213 | <<locked>> | 80% | 41,133 psi | 59% | 2470 fps | 99% |
| ADI AR 2217 | <<locked>> | 80% | 30,734 psi | 44% | 2244 fps | 96.2% |
| ADI AR 2218 | <<locked>> | 92% | 39,305 psi | 56% | 2523 fps | 95.6% |
| ADI AR 2225 | <<locked>> | 80% | 28,094 psi | 40% | 2224 fps | 98.2% |
| Alliant Power Pro Varmint | <<locked>> | 80% | 46,151 psi | 66% | 2513 fps | 99.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,794 psi | 76% | 2598 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,716 psi | 66% | 2510 fps | 99.9% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,814 psi | 60% | 2477 fps | 99.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,582 psi | 58% | 2411 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 35,041 psi | 50% | 2372 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,484 psi | 65% | 2566 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 88% | 37,057 psi | 53% | 2464 fps | 95.1% |
| Alliant Reloder-50 | <<locked>> | 94% | 39,146 psi | 56% | 2510 fps | 95.4% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 40,030 psi | 57% | 2395 fps | 96.1% |
| Bofors RP15 | <<locked>> | 80% | 38,957 psi | 56% | 2421 fps | 99.3% |
| Bofors RP30 | <<locked>> | 80% | 32,532 psi | 47% | 2316 fps | 97.3% |
| Bofors RP5 | <<locked>> | 80% | 41,814 psi | 60% | 2477 fps | 99.7% |
| Bofors RP7 | <<locked>> | 80% | 56,246 psi | 81% | 2592 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 31,517 psi | 45% | 2267 fps | 97.2% |
| Hodgdon H4350 | <<locked>> | 80% | 53,795 psi | 77% | 2592 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 38,682 psi | 56% | 2372 fps | 97.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,946 psi | 62% | 2451 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,690 psi | 71% | 2484 fps | 100% |
| Hodgdon Retumbo | 79.2 gr | 80% | 34,272 psi | 49% | 2418 fps | 99.2% |
| Hodgdon Superformance | <<locked>> | 80% | 56,971 psi | 82% | 2687 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,282 psi | 41% | 1460 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 58,827 psi | 85% | 2602 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,503 psi | 74% | 2543 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 57,479 psi | 83% | 2605 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 47,355 psi | 68% | 2474 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,860 psi | 64% | 2457 fps | 99.1% |
| IMR 7828 SSC | <<locked>> | 80% | 42,482 psi | 61% | 2507 fps | 99.3% |
| IMR 7977 Enduron | <<locked>> | 90% | 49,255 psi | 71% | 2500 fps | 95.1% |
| IMR 8133 Enduron | <<locked>> | 84% | 29,254 psi | 42% | 2257 fps | 95.7% |
| Lovex D100 | <<locked>> | 98% | 55,622 psi | 80% | 2648 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 55,056 psi | 79% | 2559 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,635 psi | 77% | 2566 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 36,216 psi | 52% | 2297 fps | 99.9% |
| Norma 204 | <<locked>> | 80% | 52,243 psi | 75% | 2595 fps | 100% |
| Norma 217 | <<locked>> | 80% | 25,657 psi | 37% | 2172 fps | 96.3% |
| Norma MRP | <<locked>> | 80% | 44,280 psi | 64% | 2539 fps | 100% |
| Norma URP | <<locked>> | 80% | 53,490 psi | 77% | 2579 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 44,643 psi | 64% | 2556 fps | 99.7% |
| Ramshot Hunter | <<locked>> | 80% | 52,301 psi | 75% | 2592 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 39,247 psi | 56% | 2428 fps | 99.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 29,008 psi | 42% | 1496 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 55,187 psi | 79% | 2618 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,664 psi | 77% | 2644 fps | 100% |
| ReloadSwiss RS 76 | 84.7 gr | 80% | 33,243 psi | 48% | 2395 fps | 99.6% |
| ReloadSwiss RS 80 | <<locked>> | 82% | 32,503 psi | 47% | 2352 fps | 95.7% |
| Rottweil R 904 | <<locked>> | 80% | 46,731 psi | 67% | 2490 fps | 99.6% |
| Rottweil R 905 | <<locked>> | 80% | 45,324 psi | 65% | 2500 fps | 99.9% |
| Rottweil R 907 | <<locked>> | 80% | 56,246 psi | 81% | 2592 fps | 100% |
| Shooters World 50 BMG | <<locked>> | 98% | 55,622 psi | 80% | 2648 fps | 95.5% |
| Shooters World Long Rifle | <<locked>> | 80% | 55,056 psi | 79% | 2559 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,635 psi | 77% | 2566 fps | 100% |
| SNPE Vectan SP 13 | <<locked>> | 98% | 40,219 psi | 58% | 2457 fps | 95.1% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,896 psi | 77% | 2520 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,991 psi | 65% | 2497 fps | 99.9% |
| Somchem S361 | <<locked>> | 80% | 47,601 psi | 68% | 2484 fps | 99.4% |
| Somchem S365 | <<locked>> | 80% | 51,140 psi | 73% | 2536 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,788 psi | 66% | 2477 fps | 100% |
| Unknown powder | <<locked>> | 80% | 56,768 psi | 82% | 2621 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 52,823 psi | 76% | 2470 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 57,116 psi | 82% | 2592 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,885 psi | 56% | 2349 fps | 99.5% |
| Vihtavuori N170 | <<locked>> | 92% | 43,207 psi | 62% | 2461 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 57,580 psi | 83% | 2635 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 45,165 psi | 65% | 2480 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 41,843 psi | 60% | 2500 fps | 98.8% |
| Vihtavuori N565 | <<locked>> | 80% | 36,564 psi | 53% | 2382 fps | 97.8% |
| Vihtavuori N568 | <<locked>> | 82% | 34,026 psi | 49% | 2372 fps | 95.7% |
| Vihtavuori N570 | 91.3 gr | 88% | 40,030 psi | 57% | 2533 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,940 psi | 77% | 2520 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 38,290 psi | 55% | 2474 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,745 psi | 66% | 2480 fps | 99.9% |
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 81 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 285gr | Warner Tool Co. Flat Line. Vihtavuori N570 delivers the highest muzzle velocity at 2,881 fps; across all powders the maximum-charge window runs from 1,637 fps to 2,881 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 (480 MPa), the top charges use 54–90 %, leaving at least 10 % headroom. The 285.0 gr projectile in 0.338" calls for a 1:9.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2218, ADI AR 2225 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, ReloadSwiss RS 76, Vihtavuori N570 rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 285gr | Warner Tool Co. Flat Line 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.