Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 250gr | Prvi Partizan FMJ-BT 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 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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Max Load - Barrel Length: 27"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 3100 | <<locked>> | 92% | 61,960 psi | 89% | 2867 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 62,584 psi | 90% | 2884 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 61,902 psi | 89% | 3002 fps | 99.8% |
| ADI APS 450 | <<locked>> | 82% | 61,322 psi | 88% | 2215 fps | 100% |
| ADI AR 2209 | <<locked>> | 88% | 59,335 psi | 85% | 2907 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 61,786 psi | 89% | 2982 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 60,002 psi | 86% | 2953 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 52,141 psi | 75% | 2953 fps | 98.4% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 54,273 psi | 78% | 2920 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 84% | 59,553 psi | 86% | 2884 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 62,700 psi | 90% | 2949 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 62,004 psi | 89% | 2972 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 92% | 59,669 psi | 86% | 2867 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 96% | 59,727 psi | 86% | 2946 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 60,858 psi | 87% | 2969 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 57,522 psi | 83% | 3002 fps | 99.1% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 48,892 psi | 70% | 2858 fps | 97.1% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 62,033 psi | 89% | 2943 fps | 99.4% |
| Bofors RP15 | <<locked>> | 94% | 60,887 psi | 87% | 2956 fps | 100% |
| Bofors RP30 | <<locked>> | 98% | 59,553 psi | 86% | 2969 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 62,004 psi | 89% | 2972 fps | 100% |
| Bofors RP7 | <<locked>> | 82% | 59,495 psi | 85% | 2828 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 61,728 psi | 89% | 2972 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 60,481 psi | 87% | 2877 fps | 100% |
| Hodgdon H4831 | <<locked>> | 94% | 60,437 psi | 87% | 2910 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 90% | 59,683 psi | 86% | 2900 fps | 99.9% |
| Hodgdon Hybrid 100V | <<locked>> | 86% | 59,843 psi | 86% | 2802 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 58,885 psi | 85% | 3041 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 60,988 psi | 88% | 2933 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,681 psi | 54% | 1781 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 62,120 psi | 89% | 2841 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 61,801 psi | 89% | 2874 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 60,800 psi | 87% | 2848 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 60,263 psi | 87% | 2841 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 61,032 psi | 88% | 2887 fps | 100% |
| IMR 7828 SSC | <<locked>> | 90% | 60,031 psi | 86% | 2966 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 96% | 59,524 psi | 86% | 2835 fps | 96.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 49,777 psi | 72% | 2848 fps | 99.8% |
| Lovex S065 | <<locked>> | 84% | 61,830 psi | 89% | 2841 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 60,278 psi | 87% | 2848 fps | 100% |
| Lovex S071 | <<locked>> | 96% | 59,538 psi | 86% | 2838 fps | 100% |
| Norma 204 | <<locked>> | 84% | 59,480 psi | 85% | 2887 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 50,647 psi | 73% | 2867 fps | 100% |
| Norma MRP | <<locked>> | 90% | 62,352 psi | 90% | 2992 fps | 100% |
| Norma URP | <<locked>> | 84% | 60,278 psi | 87% | 2864 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 60,365 psi | 87% | 2976 fps | 100% |
| Ramshot Hunter | <<locked>> | 84% | 59,350 psi | 85% | 2877 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 61,873 psi | 89% | 2943 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,624 psi | 55% | 1824 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 62,874 psi | 90% | 2907 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 61,598 psi | 88% | 2943 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 59,872 psi | 86% | 3031 fps | 100% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 59,176 psi | 85% | 3005 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 59,988 psi | 86% | 2874 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 62,642 psi | 90% | 2940 fps | 100% |
| Rottweil R 907 | <<locked>> | 82% | 59,495 psi | 85% | 2828 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 61,830 psi | 89% | 2841 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 60,278 psi | 87% | 2848 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 60,959 psi | 88% | 2802 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 62,207 psi | 89% | 2936 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 61,670 psi | 89% | 2871 fps | 100% |
| Somchem S365 | <<locked>> | 86% | 61,960 psi | 89% | 2864 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 62,917 psi | 90% | 2907 fps | 100% |
| Unknown powder | <<locked>> | 82% | 60,336 psi | 87% | 2864 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 62,859 psi | 90% | 2785 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 60,597 psi | 87% | 2828 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 60,597 psi | 87% | 2864 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 55,506 psi | 80% | 2838 fps | 97.3% |
| Vihtavuori N550 | <<locked>> | 82% | 61,206 psi | 88% | 2877 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 61,772 psi | 89% | 2897 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 62,323 psi | 90% | 3009 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 62,149 psi | 89% | 2986 fps | 100% |
| Vihtavuori N568 | <<locked>> | 98% | 59,683 psi | 86% | 3005 fps | 99.8% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 61,482 psi | 88% | 3071 fps | 99.3% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 61,525 psi | 88% | 2802 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 92% | 59,669 psi | 86% | 2966 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 60,278 psi | 87% | 2874 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% | 41,568 psi | 60% | 2566 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 54,795 psi | 79% | 2782 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 40,698 psi | 58% | 2641 fps | 96.5% |
| ADI APS 450 | <<locked>> | 80% | 59,364 psi | 85% | 2188 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 45,513 psi | 65% | 2690 fps | 99.6% |
| ADI AR 2213 | <<locked>> | 80% | 40,799 psi | 59% | 2635 fps | 98.2% |
| ADI AR 2217 | <<locked>> | 82% | 32,561 psi | 47% | 2444 fps | 95.8% |
| ADI AR 2218 | <<locked>> | 94% | 42,047 psi | 60% | 2746 fps | 95.4% |
| ADI AR 2225 | <<locked>> | 80% | 27,891 psi | 40% | 2359 fps | 96.9% |
| Alliant Reloder-16 | <<locked>> | 80% | 52,330 psi | 75% | 2785 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 45,498 psi | 65% | 2684 fps | 99.6% |
| Alliant Reloder-22 | <<locked>> | 80% | 41,466 psi | 60% | 2641 fps | 99.2% |
| Alliant Reloder-23 | <<locked>> | 80% | 40,277 psi | 58% | 2582 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,766 psi | 50% | 2526 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 45,324 psi | 65% | 2746 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 42,670 psi | 61% | 2743 fps | 96% |
| Alliant Reloder-50 | <<locked>> | 96% | 42,090 psi | 60% | 2726 fps | 95.2% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 42,467 psi | 61% | 2612 fps | 95.9% |
| Bofors RP15 | <<locked>> | 80% | 38,711 psi | 56% | 2582 fps | 98.6% |
| Bofors RP30 | <<locked>> | 80% | 32,300 psi | 46% | 2461 fps | 96% |
| Bofors RP5 | <<locked>> | 80% | 41,466 psi | 60% | 2641 fps | 99.2% |
| Bofors RP7 | <<locked>> | 80% | 55,941 psi | 80% | 2782 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 31,314 psi | 45% | 2411 fps | 95.9% |
| Hodgdon H4350 | <<locked>> | 80% | 53,505 psi | 77% | 2779 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 38,334 psi | 55% | 2530 fps | 96.9% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,627 psi | 61% | 2618 fps | 98% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 49,342 psi | 71% | 2664 fps | 100% |
| Hodgdon Retumbo | 87.1 gr | 80% | 33,997 psi | 49% | 2569 fps | 98.3% |
| Hodgdon Superformance | <<locked>> | 80% | 56,710 psi | 81% | 2877 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,282 psi | 41% | 1591 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 58,450 psi | 84% | 2795 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 51,184 psi | 74% | 2723 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 57,232 psi | 82% | 2799 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 47,021 psi | 68% | 2654 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,585 psi | 64% | 2625 fps | 98.5% |
| IMR 7828 SSC | 88.9 gr | 80% | 42,076 psi | 60% | 2671 fps | 98.6% |
| IMR 7977 Enduron | <<locked>> | 94% | 55,738 psi | 80% | 2779 fps | 95.6% |
| IMR 8133 Enduron | <<locked>> | 86% | 31,067 psi | 45% | 2451 fps | 95.3% |
| Lovex S065 | <<locked>> | 80% | 54,795 psi | 79% | 2746 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 53,359 psi | 77% | 2753 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,897 psi | 52% | 2451 fps | 99.6% |
| Norma 204 | <<locked>> | 80% | 51,938 psi | 75% | 2776 fps | 100% |
| Norma 217 | <<locked>> | 82% | 27,224 psi | 39% | 2362 fps | 95.8% |
| Norma MRP | <<locked>> | 80% | 44,005 psi | 63% | 2713 fps | 100% |
| Norma URP | <<locked>> | 80% | 53,185 psi | 76% | 2766 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 44,411 psi | 64% | 2730 fps | 99.3% |
| Ramshot Hunter | <<locked>> | 80% | 51,996 psi | 75% | 2776 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,914 psi | 56% | 2589 fps | 99.4% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,935 psi | 42% | 1631 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,839 psi | 79% | 2805 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 53,272 psi | 77% | 2831 fps | 100% |
| ReloadSwiss RS 76 | 93.2 gr | 80% | 33,112 psi | 48% | 2543 fps | 99% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 34,824 psi | 50% | 2559 fps | 95.4% |
| Rottweil R 904 | <<locked>> | 80% | 46,543 psi | 67% | 2664 fps | 99.2% |
| Rottweil R 905 | <<locked>> | 80% | 45,034 psi | 65% | 2674 fps | 99.6% |
| Rottweil R 907 | <<locked>> | 80% | 55,941 psi | 80% | 2782 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,795 psi | 79% | 2746 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 53,359 psi | 77% | 2753 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,664 psi | 77% | 2703 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,686 psi | 64% | 2667 fps | 99.6% |
| Somchem S361 | <<locked>> | 80% | 47,282 psi | 68% | 2651 fps | 98.8% |
| Somchem S365 | <<locked>> | 80% | 50,763 psi | 73% | 2720 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 45,469 psi | 65% | 2648 fps | 99.9% |
| Unknown powder | <<locked>> | 80% | 56,507 psi | 81% | 2815 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 52,475 psi | 75% | 2654 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 56,768 psi | 82% | 2779 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,624 psi | 55% | 2510 fps | 99% |
| Vihtavuori N170 | <<locked>> | 94% | 45,774 psi | 66% | 2671 fps | 95% |
| Vihtavuori N550 | <<locked>> | 80% | 57,406 psi | 82% | 2828 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,831 psi | 64% | 2654 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 41,655 psi | 60% | 2667 fps | 98% |
| Vihtavuori N565 | <<locked>> | 80% | 36,230 psi | 52% | 2533 fps | 96.7% |
| Vihtavuori N568 | <<locked>> | 84% | 36,274 psi | 52% | 2579 fps | 95.3% |
| Vihtavuori N570 | <<locked>> | 90% | 42,844 psi | 62% | 2753 fps | 95.5% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,809 psi | 77% | 2707 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,927 psi | 54% | 2641 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 45,542 psi | 65% | 2654 fps | 99.6% |
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 84 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 250gr | Prvi Partizan FMJ-BT. Vihtavuori N570 delivers the highest muzzle velocity at 3,071 fps; across all powders the maximum-charge window runs from 1,781 fps to 3,071 fps. Accurate 8700 gives the best case fill at 100 %, and 84 of the 84 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, IMR 7828 SSC rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 250gr | Prvi Partizan FMJ-BT 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.