Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 250gr | Sierra MatchKing bullet and 77 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 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.
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Max Load - Barrel Length: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 92% | 61,772 psi | 89% | 2864 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 62,511 psi | 90% | 2881 fps | 100% |
| Accurate MAGPRO | <<locked>> | 90% | 60,771 psi | 87% | 2989 fps | 99.9% |
| ADI APS 450 | <<locked>> | 82% | 61,264 psi | 88% | 2215 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 59,277 psi | 85% | 2907 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 61,583 psi | 88% | 2979 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 59,814 psi | 86% | 2949 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 52,011 psi | 75% | 2949 fps | 98.3% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,244 psi | 78% | 2920 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 59,509 psi | 85% | 2881 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 62,642 psi | 90% | 2946 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 61,801 psi | 89% | 2969 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 59,669 psi | 86% | 2867 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 59,698 psi | 86% | 2943 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 60,829 psi | 87% | 2969 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 57,537 psi | 83% | 3002 fps | 99% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 48,718 psi | 70% | 2854 fps | 97.1% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 61,859 psi | 89% | 2940 fps | 99.4% |
| Bofors RP15 | <<locked>> | 94% | 60,901 psi | 87% | 2959 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 59,335 psi | 85% | 2966 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 61,801 psi | 89% | 2969 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 59,451 psi | 85% | 2828 fps | 100% |
| Hodgdon H1000 | <<locked>> | 98% | 61,728 psi | 89% | 2972 fps | 100% |
| Hodgdon H414 | <<locked>> | 82% | 59,683 psi | 86% | 2887 fps | 100% |
| Hodgdon H4350 | <<locked>> | 82% | 61,902 psi | 89% | 2897 fps | 100% |
| Hodgdon H4831 | <<locked>> | 90% | 60,785 psi | 87% | 2913 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 90% | 59,524 psi | 86% | 2897 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 59,596 psi | 86% | 2802 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 62,961 psi | 90% | 3094 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 60,945 psi | 88% | 2933 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,608 psi | 54% | 1778 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 61,772 psi | 89% | 2871 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 60,771 psi | 87% | 2848 fps | 100% |
| IMR 4831 | <<locked>> | 86% | 62,569 psi | 90% | 2871 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 61,032 psi | 88% | 2887 fps | 100% |
| IMR 7828 SSC | <<locked>> | 92% | 59,814 psi | 86% | 2963 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 59,350 psi | 85% | 2831 fps | 96.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,632 psi | 71% | 2844 fps | 99.8% |
| Lovex S065 | <<locked>> | 84% | 61,815 psi | 89% | 2841 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 60,249 psi | 87% | 2848 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 59,350 psi | 85% | 2835 fps | 100% |
| Norma 204 | <<locked>> | 84% | 59,422 psi | 85% | 2887 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 50,459 psi | 72% | 2864 fps | 100% |
| Norma MRP | <<locked>> | 90% | 62,149 psi | 89% | 2986 fps | 100% |
| Norma URP | <<locked>> | 84% | 60,263 psi | 87% | 2861 fps | 100% |
| Ramshot Grand | <<locked>> | 92% | 61,337 psi | 88% | 2986 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 59,292 psi | 85% | 2877 fps | 100% |
| Ramshot Magnum | <<locked>> | 94% | 59,495 psi | 85% | 2913 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,551 psi | 55% | 1821 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 62,656 psi | 90% | 2907 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 61,366 psi | 88% | 2940 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 59,872 psi | 86% | 3031 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 59,001 psi | 85% | 3002 fps | 99.9% |
| Rottweil R 904 | <<locked>> | 88% | 59,930 psi | 86% | 2874 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 62,395 psi | 90% | 2936 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 59,451 psi | 85% | 2828 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 61,815 psi | 89% | 2841 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 60,249 psi | 87% | 2848 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 60,901 psi | 87% | 2802 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 61,975 psi | 89% | 2933 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 61,467 psi | 88% | 2864 fps | 100% |
| Somchem S365 | <<locked>> | 86% | 61,946 psi | 89% | 2861 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 62,714 psi | 90% | 2900 fps | 100% |
| Vihtavuori N150 | <<locked>> | 82% | 62,004 psi | 89% | 2772 fps | 100% |
| Vihtavuori N160 | <<locked>> | 84% | 61,946 psi | 89% | 2848 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 62,598 psi | 90% | 2887 fps | 100% |
| Vihtavuori N170 | <<locked>> | 98% | 61,627 psi | 89% | 2927 fps | 98.3% |
| Vihtavuori N550 | <<locked>> | 84% | 61,119 psi | 88% | 2858 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 61,728 psi | 89% | 2897 fps | 100% |
| Vihtavuori N560 | <<locked>> | 90% | 61,540 psi | 88% | 2995 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 62,178 psi | 89% | 2986 fps | 100% |
| Vihtavuori N568 | <<locked>> | 98% | 59,509 psi | 85% | 3002 fps | 99.8% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 60,771 psi | 87% | 3068 fps | 99.2% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 61,525 psi | 88% | 2799 fps | 100% |
| Winchester 760 | <<locked>> | 82% | 59,843 psi | 86% | 2890 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 59,669 psi | 86% | 2966 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 62,961 psi | 90% | 2907 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% | 41,495 psi | 60% | 2562 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 54,737 psi | 79% | 2782 fps | 100% |
| Accurate MAGPRO | 91.9 gr | 80% | 42,801 psi | 61% | 2690 fps | 97.7% |
| ADI APS 450 | <<locked>> | 80% | 59,292 psi | 85% | 2188 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 45,484 psi | 65% | 2687 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 80% | 40,756 psi | 59% | 2635 fps | 98.2% |
| ADI AR 2217 | <<locked>> | 82% | 32,547 psi | 47% | 2444 fps | 95.8% |
| ADI AR 2218 | <<locked>> | 94% | 41,916 psi | 60% | 2743 fps | 95.3% |
| ADI AR 2225 | <<locked>> | 80% | 27,789 psi | 40% | 2359 fps | 96.8% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,286 psi | 75% | 2782 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,469 psi | 65% | 2684 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,423 psi | 60% | 2641 fps | 99.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,248 psi | 58% | 2582 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,722 psi | 50% | 2526 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,252 psi | 65% | 2743 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 42,641 psi | 61% | 2743 fps | 95.9% |
| Alliant Reloder-50 | <<locked>> | 96% | 41,930 psi | 60% | 2723 fps | 95.1% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 42,467 psi | 61% | 2608 fps | 95.8% |
| Bofors RP15 | <<locked>> | 80% | 38,551 psi | 55% | 2579 fps | 98.6% |
| Bofors RP30 | <<locked>> | 80% | 32,271 psi | 46% | 2461 fps | 96% |
| Bofors RP5 | <<locked>> | 80% | 41,423 psi | 60% | 2641 fps | 99.2% |
| Bofors RP7 | <<locked>> | 80% | 55,898 psi | 80% | 2779 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 32,996 psi | 47% | 2457 fps | 96.7% |
| Hodgdon H414 | <<locked>> | 80% | 55,956 psi | 80% | 2835 fps | 100% |
| Hodgdon H4350 | <<locked>> | 80% | 58,044 psi | 83% | 2844 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 43,395 psi | 62% | 2631 fps | 98.2% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,612 psi | 61% | 2618 fps | 98% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,284 psi | 71% | 2661 fps | 100% |
| Hodgdon Retumbo | 86.9 gr | 80% | 33,852 psi | 49% | 2562 fps | 98.3% |
| Hodgdon Superformance | <<locked>> | 80% | 56,695 psi | 81% | 2874 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,210 psi | 41% | 1591 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,140 psi | 73% | 2720 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 57,029 psi | 82% | 2795 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 51,576 psi | 74% | 2723 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,527 psi | 64% | 2621 fps | 98.5% |
| IMR 7828 SSC | <<locked>> | 80% | 39,450 psi | 57% | 2615 fps | 97.9% |
| IMR 7977 Enduron | <<locked>> | 94% | 55,753 psi | 80% | 2779 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 86% | 30,922 psi | 44% | 2448 fps | 95.2% |
| Lovex S065 | <<locked>> | 80% | 54,781 psi | 79% | 2746 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,171 psi | 76% | 2746 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,824 psi | 51% | 2448 fps | 99.6% |
| Norma 204 | <<locked>> | 80% | 51,924 psi | 75% | 2776 fps | 100% |
| Norma 217 | <<locked>> | 82% | 27,195 psi | 39% | 2359 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 43,830 psi | 63% | 2710 fps | 100% |
| Norma URP | <<locked>> | 80% | 52,997 psi | 76% | 2762 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 39,407 psi | 57% | 2628 fps | 98.3% |
| Ramshot Hunter | <<locked>> | 80% | 51,953 psi | 75% | 2772 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 35,360 psi | 51% | 2510 fps | 98.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,993 psi | 42% | 1631 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,795 psi | 79% | 2805 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,229 psi | 76% | 2831 fps | 100% |
| ReloadSwiss RS 76 | 93.1 gr | 80% | 33,054 psi | 47% | 2543 fps | 99% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 34,809 psi | 50% | 2559 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 46,485 psi | 67% | 2661 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 80% | 44,962 psi | 65% | 2671 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 80% | 55,898 psi | 80% | 2779 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,781 psi | 79% | 2746 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,171 psi | 76% | 2746 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,664 psi | 77% | 2703 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,672 psi | 64% | 2667 fps | 99.6% |
| Somchem S361 | <<locked>> | 80% | 47,253 psi | 68% | 2651 fps | 98.8% |
| Somchem S365 | <<locked>> | 80% | 50,705 psi | 73% | 2717 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,411 psi | 65% | 2648 fps | 99.9% |
| Vihtavuori N150 | <<locked>> | 80% | 58,131 psi | 84% | 2723 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 54,520 psi | 78% | 2753 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 39,682 psi | 57% | 2533 fps | 99.2% |
| Vihtavuori N170 | <<locked>> | 90% | 47,123 psi | 68% | 2697 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 53,795 psi | 77% | 2762 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,773 psi | 64% | 2651 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 43,627 psi | 63% | 2703 fps | 98.4% |
| Vihtavuori N565 | <<locked>> | 80% | 36,172 psi | 52% | 2530 fps | 96.6% |
| Vihtavuori N568 | <<locked>> | 84% | 36,143 psi | 52% | 2575 fps | 95.3% |
| Vihtavuori N570 | <<locked>> | 90% | 42,467 psi | 61% | 2749 fps | 95.4% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,795 psi | 77% | 2703 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 56,115 psi | 81% | 2838 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,884 psi | 54% | 2641 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 41,713 psi | 60% | 2582 fps | 99.2% |
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 83 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 250gr | Sierra MatchKing. Hodgdon Retumbo delivers the highest muzzle velocity at 3,094 fps; across all powders the maximum-charge window runs from 1,778 fps to 3,094 fps. Accurate 8700 gives the best case fill at 100 %, and 83 of the 83 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 250.0 gr projectile in 0.338" calls for a 1:12.5 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, ReloadSwiss RS 76, Accurate MAGPRO rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 250gr | Sierra MatchKing they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 8700, Ramshot LRT, SNPE Vectan SP 13 burn incompletely and react more sensitively to barrel length and temperature. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.