Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 255gr | AERO SOLR,- smax:19.50 bullet and 85 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 IMR 7828 SSC.
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 2700 | <<locked>> | 82% | 60,858 psi | 87% | 2766 fps | 100% |
| Accurate 3100 | <<locked>> | 94% | 62,033 psi | 89% | 2835 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 58,900 psi | 85% | 2805 fps | 100% |
| Accurate MAGPRO | <<locked>> | 94% | 62,134 psi | 89% | 2972 fps | 99.8% |
| ADI APS 450 | <<locked>> | 82% | 61,279 psi | 88% | 2169 fps | 100% |
| ADI AR 2208 | <<locked>> | 82% | 62,598 psi | 90% | 2799 fps | 100% |
| ADI AR 2209 | <<locked>> | 90% | 60,118 psi | 86% | 2884 fps | 100% |
| ADI AR 2213 | <<locked>> | 94% | 62,410 psi | 90% | 2956 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 56,173 psi | 81% | 2867 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 48,486 psi | 70% | 2848 fps | 97.4% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 50,517 psi | 73% | 2835 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 60,379 psi | 87% | 2861 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 82% | 61,627 psi | 89% | 2867 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 59,451 psi | 85% | 2871 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 94% | 62,337 psi | 90% | 2943 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 59,814 psi | 86% | 2838 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 59,814 psi | 86% | 2913 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 90% | 61,090 psi | 88% | 2943 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 53,026 psi | 76% | 2900 fps | 98.3% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 62,932 psi | 90% | 2917 fps | 99.4% |
| Bofors RP15 | <<locked>> | 96% | 61,192 psi | 88% | 2930 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 59,379 psi | 85% | 2936 fps | 100% |
| Bofors RP5 | <<locked>> | 94% | 62,337 psi | 90% | 2943 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 60,423 psi | 87% | 2805 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 57,827 psi | 83% | 2890 fps | 100% |
| Hodgdon H414 | <<locked>> | 82% | 61,627 psi | 89% | 2877 fps | 100% |
| Hodgdon H4350 | <<locked>> | 86% | 61,569 psi | 88% | 2854 fps | 100% |
| Hodgdon H4831 | <<locked>> | 96% | 60,988 psi | 88% | 2881 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 92% | 60,408 psi | 87% | 2874 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 60,365 psi | 87% | 2776 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 58,755 psi | 84% | 3005 fps | 100% |
| Hodgdon Superformance | <<locked>> | 84% | 61,859 psi | 89% | 2910 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,391 psi | 54% | 1742 fps | 100% |
| IMR 4064 | <<locked>> | 82% | 61,583 psi | 88% | 2772 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 59,640 psi | 86% | 2772 fps | 100% |
| IMR 4350 | <<locked>> | 88% | 62,772 psi | 90% | 2848 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 84% | 61,946 psi | 89% | 2825 fps | 100% |
| IMR 4831 | <<locked>> | 90% | 60,742 psi | 87% | 2815 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 61,975 psi | 89% | 2864 fps | 100% |
| IMR 7828 SSC | <<locked>> | 92% | 60,423 psi | 87% | 2940 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 98% | 60,452 psi | 87% | 2808 fps | 96.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 45,963 psi | 66% | 2753 fps | 99.4% |
| Lovex S065 | <<locked>> | 86% | 62,816 psi | 90% | 2818 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 61,017 psi | 88% | 2822 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 59,437 psi | 85% | 2802 fps | 100% |
| Norma 204 | <<locked>> | 86% | 60,408 psi | 87% | 2864 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 46,354 psi | 67% | 2772 fps | 100% |
| Norma MRP | <<locked>> | 92% | 62,656 psi | 90% | 2963 fps | 100% |
| Norma URP | <<locked>> | 86% | 60,974 psi | 88% | 2838 fps | 100% |
| Ramshot Grand | <<locked>> | 90% | 60,988 psi | 88% | 2949 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 60,046 psi | 86% | 2854 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 62,366 psi | 90% | 2917 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,319 psi | 55% | 1785 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 59,321 psi | 85% | 2831 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 86% | 62,323 psi | 90% | 2917 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 59,770 psi | 86% | 3002 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 58,856 psi | 85% | 2972 fps | 99.9% |
| Rottweil R 903 | <<locked>> | 82% | 62,381 psi | 90% | 2789 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 60,800 psi | 87% | 2848 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 59,161 psi | 85% | 2861 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 60,423 psi | 87% | 2805 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 86% | 62,816 psi | 90% | 2818 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 61,017 psi | 88% | 2822 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 61,235 psi | 88% | 2648 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 86% | 62,076 psi | 89% | 2779 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 92% | 62,830 psi | 90% | 2910 fps | 100% |
| Somchem S355 | <<locked>> | 82% | 61,511 psi | 88% | 2779 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 62,642 psi | 90% | 2844 fps | 100% |
| Somchem S365 | <<locked>> | 88% | 62,468 psi | 90% | 2835 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 59,393 psi | 85% | 2825 fps | 100% |
| Unknown powder | <<locked>> | 84% | 61,076 psi | 88% | 2838 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 60,002 psi | 86% | 2717 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 61,409 psi | 88% | 2805 fps | 100% |
| Vihtavuori N165 | <<locked>> | 96% | 61,119 psi | 88% | 2835 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 51,938 psi | 75% | 2746 fps | 96.4% |
| Vihtavuori N550 | <<locked>> | 84% | 61,946 psi | 89% | 2854 fps | 100% |
| Vihtavuori N555 | <<locked>> | 92% | 61,830 psi | 89% | 2864 fps | 100% |
| Vihtavuori N560 | <<locked>> | 94% | 62,743 psi | 90% | 2982 fps | 100% |
| Vihtavuori N565 | <<locked>> | 98% | 62,279 psi | 89% | 2953 fps | 100% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 59,640 psi | 86% | 2972 fps | 99.8% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 57,014 psi | 82% | 2972 fps | 98.7% |
| Winchester 6.5 StaBALL | <<locked>> | 86% | 62,584 psi | 90% | 2779 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 61,627 psi | 89% | 2877 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 59,393 psi | 85% | 2933 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 61,076 psi | 88% | 2848 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 2700 | <<locked>> | 80% | 57,058 psi | 82% | 2717 fps | 100% |
| Accurate 3100 | <<locked>> | 80% | 38,479 psi | 55% | 2480 fps | 99.8% |
| Accurate 4350 | <<locked>> | 80% | 51,401 psi | 74% | 2703 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 37,695 psi | 54% | 2549 fps | 95.4% |
| ADI APS 450 | <<locked>> | 80% | 59,219 psi | 85% | 2142 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 58,856 psi | 85% | 2749 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 42,960 psi | 62% | 2612 fps | 99.3% |
| ADI AR 2213 | <<locked>> | 80% | 38,276 psi | 55% | 2552 fps | 97.5% |
| ADI AR 2217 | <<locked>> | 84% | 32,430 psi | 47% | 2415 fps | 95.6% |
| ADI AR 2218 | <<locked>> | 96% | 41,901 psi | 60% | 2710 fps | 95.1% |
| ADI AR 2225 | <<locked>> | 80% | 25,701 psi | 37% | 2267 fps | 95.3% |
| Alliant Reloder-16 | <<locked>> | 80% | 49,588 psi | 71% | 2713 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 80% | 57,363 psi | 82% | 2815 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 42,859 psi | 62% | 2605 fps | 99.3% |
| Alliant Reloder-22 | <<locked>> | 80% | 38,696 psi | 56% | 2559 fps | 98.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 37,420 psi | 54% | 2503 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 32,271 psi | 46% | 2444 fps | 99.5% |
| Alliant Reloder-26 | <<locked>> | 80% | 41,785 psi | 60% | 2661 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 94% | 42,206 psi | 61% | 2707 fps | 95.7% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 40,350 psi | 58% | 2533 fps | 95% |
| Bofors RP15 | <<locked>> | 80% | 35,969 psi | 52% | 2497 fps | 97.9% |
| Bofors RP30 | <<locked>> | 82% | 31,807 psi | 46% | 2428 fps | 95.8% |
| Bofors RP5 | <<locked>> | 80% | 38,696 psi | 56% | 2559 fps | 98.7% |
| Bofors RP7 | <<locked>> | 80% | 53,301 psi | 77% | 2707 fps | 100% |
| Hodgdon H1000 | <<locked>> | 82% | 31,154 psi | 45% | 2382 fps | 95.7% |
| Hodgdon H414 | <<locked>> | 80% | 57,696 psi | 83% | 2825 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 50,879 psi | 73% | 2703 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 36,027 psi | 52% | 2451 fps | 96% |
| Hodgdon H4831 SC | <<locked>> | 80% | 40,103 psi | 58% | 2539 fps | 97.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 46,441 psi | 67% | 2592 fps | 100% |
| Hodgdon Retumbo | 82.9 gr | 80% | 31,502 psi | 45% | 2474 fps | 97.3% |
| Hodgdon Superformance | <<locked>> | 80% | 53,461 psi | 77% | 2799 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,065 psi | 40% | 1558 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 57,841 psi | 83% | 2726 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 56,086 psi | 81% | 2723 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 48,733 psi | 70% | 2651 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 54,665 psi | 79% | 2726 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 44,208 psi | 64% | 2579 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 42,308 psi | 61% | 2549 fps | 98% |
| IMR 7828 SSC | 84.6 gr | 80% | 39,320 psi | 56% | 2585 fps | 97.9% |
| IMR 7977 Enduron | <<locked>> | 96% | 56,521 psi | 81% | 2753 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 90% | 32,489 psi | 47% | 2467 fps | 95.9% |
| Lovex S065 | <<locked>> | 80% | 52,098 psi | 75% | 2674 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 50,473 psi | 73% | 2674 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 33,040 psi | 47% | 2365 fps | 99.1% |
| Norma 204 | <<locked>> | 80% | 49,211 psi | 71% | 2700 fps | 99.8% |
| Norma 217 | <<locked>> | 84% | 26,469 psi | 38% | 2320 fps | 95.3% |
| Norma MRP | <<locked>> | 80% | 40,843 psi | 59% | 2625 fps | 99.8% |
| Norma URP | <<locked>> | 80% | 50,198 psi | 72% | 2690 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 41,249 psi | 59% | 2638 fps | 98.7% |
| Ramshot Hunter | <<locked>> | 80% | 49,110 psi | 71% | 2700 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,940 psi | 52% | 2500 fps | 98.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,689 psi | 41% | 1594 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 51,692 psi | 74% | 2730 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 50,140 psi | 72% | 2756 fps | 100% |
| ReloadSwiss RS 76 | 88.7 gr | 80% | 30,443 psi | 44% | 2444 fps | 98% |
| ReloadSwiss RS 80 | <<locked>> | 86% | 34,301 psi | 49% | 2526 fps | 95.2% |
| Rottweil R 903 | <<locked>> | 80% | 58,363 psi | 84% | 2740 fps | 100% |
| Rottweil R 904 | <<locked>> | 80% | 43,947 psi | 63% | 2585 fps | 98.7% |
| Rottweil R 905 | <<locked>> | 80% | 42,308 psi | 61% | 2592 fps | 99.3% |
| Rottweil R 907 | <<locked>> | 80% | 53,301 psi | 77% | 2707 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 52,098 psi | 75% | 2674 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 50,473 psi | 73% | 2674 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 57,479 psi | 83% | 2602 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 51,010 psi | 73% | 2631 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 41,974 psi | 60% | 2589 fps | 99.2% |
| Somchem S355 | <<locked>> | 80% | 57,798 psi | 83% | 2733 fps | 100% |
| Somchem S361 | <<locked>> | 80% | 44,744 psi | 64% | 2575 fps | 98.3% |
| Somchem S365 | <<locked>> | 80% | 47,688 psi | 69% | 2648 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 42,685 psi | 61% | 2569 fps | 99.7% |
| Unknown powder | <<locked>> | 80% | 53,592 psi | 77% | 2740 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 49,937 psi | 72% | 2585 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 53,751 psi | 77% | 2707 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 36,042 psi | 52% | 2431 fps | 98.4% |
| Vihtavuori N170 | <<locked>> | 98% | 48,762 psi | 70% | 2694 fps | 95.7% |
| Vihtavuori N550 | <<locked>> | 80% | 54,375 psi | 78% | 2753 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 41,713 psi | 60% | 2575 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 38,798 psi | 56% | 2579 fps | 97.2% |
| Vihtavuori N565 | <<locked>> | 80% | 33,344 psi | 48% | 2441 fps | 95.5% |
| Vihtavuori N568 | <<locked>> | 86% | 35,795 psi | 51% | 2543 fps | 95.1% |
| Vihtavuori N570 | <<locked>> | 92% | 42,424 psi | 61% | 2720 fps | 95.3% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 50,966 psi | 73% | 2638 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 57,696 psi | 83% | 2825 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 34,461 psi | 50% | 2552 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 42,728 psi | 61% | 2572 fps | 99.3% |
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 85 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 255gr | AERO SOLR,- smax:19.50. Hodgdon Retumbo delivers the highest muzzle velocity at 3,005 fps; across all powders the maximum-charge window runs from 1,742 fps to 3,005 fps. ADI AR 2217 gives the best case fill at 100 %, and 85 of the 85 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 255.0 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 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, IMR 7828 SSC rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 255gr | AERO SOLR,- smax:19.50 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.