Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 250gr | RWS Speed Tip Professional 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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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% | 61,003 psi | 88% | 2851 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 61,830 psi | 89% | 2871 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 60,829 psi | 87% | 2982 fps | 99.7% |
| ADI APS 450 | <<locked>> | 82% | 61,380 psi | 88% | 2208 fps | 100% |
| ADI AR 2209 | <<locked>> | 90% | 62,453 psi | 90% | 2943 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 60,829 psi | 87% | 2966 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 58,958 psi | 85% | 2936 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 51,227 psi | 74% | 2930 fps | 98.1% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 53,243 psi | 76% | 2904 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 62,729 psi | 90% | 2920 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 61,946 psi | 89% | 2933 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 61,061 psi | 88% | 2956 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 62,569 psi | 90% | 2900 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 62,758 psi | 90% | 2979 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 59,814 psi | 86% | 2953 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 56,434 psi | 81% | 2979 fps | 98.8% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 47,718 psi | 69% | 2835 fps | 96.8% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 61,177 psi | 88% | 2927 fps | 99.3% |
| Bofors RP15 | <<locked>> | 94% | 59,973 psi | 86% | 2943 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 62,439 psi | 90% | 3002 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 61,061 psi | 88% | 2956 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 62,613 psi | 90% | 2864 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 60,640 psi | 87% | 2956 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 59,857 psi | 86% | 2864 fps | 100% |
| Hodgdon H4831 | <<locked>> | 94% | 59,538 psi | 86% | 2890 fps | 99.9% |
| Hodgdon H4831 SC | <<locked>> | 92% | 62,946 psi | 90% | 2936 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 62,874 psi | 90% | 2835 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 61,960 psi | 89% | 3077 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 60,017 psi | 86% | 2917 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,652 psi | 54% | 1775 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 61,467 psi | 88% | 2828 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 61,032 psi | 88% | 2858 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 60,176 psi | 86% | 2835 fps | 100% |
| IMR 4831 | <<locked>> | 88% | 59,408 psi | 85% | 2828 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 60,220 psi | 87% | 2871 fps | 100% |
| IMR 7828 SSC | <<locked>> | 90% | 59,045 psi | 85% | 2949 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 98% | 62,671 psi | 90% | 2871 fps | 96.8% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 48,791 psi | 70% | 2825 fps | 99.7% |
| Lovex S065 | <<locked>> | 84% | 61,177 psi | 88% | 2828 fps | 100% |
| Lovex S070 | <<locked>> | 84% | 59,669 psi | 86% | 2835 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 62,337 psi | 90% | 2867 fps | 100% |
| Norma 204 | <<locked>> | 86% | 62,743 psi | 90% | 2923 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 49,545 psi | 71% | 2848 fps | 100% |
| Norma MRP | <<locked>> | 90% | 61,206 psi | 88% | 2972 fps | 100% |
| Norma URP | <<locked>> | 84% | 59,611 psi | 86% | 2851 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 59,321 psi | 85% | 2956 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 62,497 psi | 90% | 2913 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 60,597 psi | 87% | 2923 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,595 psi | 55% | 1818 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 61,844 psi | 89% | 2894 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 60,524 psi | 87% | 2927 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 96% | 58,769 psi | 84% | 3015 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 62,540 psi | 90% | 3048 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 59,248 psi | 85% | 2858 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 61,641 psi | 89% | 2923 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 62,613 psi | 90% | 2864 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 61,177 psi | 88% | 2828 fps | 100% |
| Shooters World SW4350 | <<locked>> | 84% | 59,669 psi | 86% | 2835 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 60,162 psi | 86% | 2785 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 61,206 psi | 88% | 2920 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 60,742 psi | 87% | 2851 fps | 99.9% |
| Somchem S365 | <<locked>> | 86% | 61,032 psi | 88% | 2848 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 62,004 psi | 89% | 2890 fps | 100% |
| Unknown powder | <<locked>> | 82% | 59,480 psi | 85% | 2848 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 62,163 psi | 89% | 2772 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 59,741 psi | 86% | 2815 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 59,741 psi | 86% | 2848 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 54,621 psi | 78% | 2818 fps | 97% |
| Vihtavuori N550 | <<locked>> | 82% | 60,336 psi | 87% | 2861 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 60,916 psi | 88% | 2881 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 61,366 psi | 88% | 2992 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 61,119 psi | 88% | 2966 fps | 100% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 62,714 psi | 90% | 3041 fps | 99.9% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 60,249 psi | 87% | 3048 fps | 99.1% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 60,814 psi | 87% | 2789 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 62,946 psi | 90% | 3002 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 59,408 psi | 85% | 2858 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% | 40,944 psi | 59% | 2549 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 54,041 psi | 78% | 2769 fps | 100% |
| Accurate MAGPRO | 90.8 gr | 80% | 39,987 psi | 57% | 2621 fps | 96.2% |
| ADI APS 450 | <<locked>> | 80% | 59,205 psi | 85% | 2178 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 44,875 psi | 64% | 2674 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 80% | 40,205 psi | 58% | 2618 fps | 98% |
| ADI AR 2217 | <<locked>> | 82% | 32,111 psi | 46% | 2428 fps | 95.5% |
| ADI AR 2218 | <<locked>> | 96% | 44,280 psi | 64% | 2789 fps | 96% |
| ADI AR 2225 | <<locked>> | 80% | 27,383 psi | 39% | 2339 fps | 96.5% |
| Alliant Reloder-16 | <<locked>> | 80% | 51,706 psi | 74% | 2772 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 44,875 psi | 64% | 2667 fps | 99.5% |
| Alliant Reloder-22 | <<locked>> | 80% | 40,843 psi | 59% | 2625 fps | 99.1% |
| Alliant Reloder-23 | <<locked>> | 80% | 39,595 psi | 57% | 2566 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 34,171 psi | 49% | 2510 fps | 99.8% |
| Alliant Reloder-26 | <<locked>> | 80% | 44,483 psi | 64% | 2730 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 92% | 41,829 psi | 60% | 2720 fps | 95.6% |
| Alliant Reloder-50 | <<locked>> | 98% | 44,280 psi | 64% | 2769 fps | 95.8% |
| Baschieri & Pellagri 109 | <<locked>> | 82% | 41,959 psi | 60% | 2592 fps | 95.5% |
| Bofors RP15 | <<locked>> | 80% | 38,116 psi | 55% | 2566 fps | 98.4% |
| Bofors RP30 | <<locked>> | 80% | 31,720 psi | 46% | 2444 fps | 95.7% |
| Bofors RP5 | <<locked>> | 80% | 40,843 psi | 59% | 2625 fps | 99.1% |
| Bofors RP7 | <<locked>> | 80% | 55,274 psi | 79% | 2766 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 30,835 psi | 44% | 2395 fps | 95.5% |
| Hodgdon H4350 | <<locked>> | 80% | 52,823 psi | 76% | 2762 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 37,884 psi | 54% | 2513 fps | 96.6% |
| Hodgdon H4831 SC | <<locked>> | 80% | 42,061 psi | 60% | 2602 fps | 97.8% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,588 psi | 70% | 2648 fps | 100% |
| Hodgdon Retumbo | 85.8 gr | 80% | 33,344 psi | 48% | 2546 fps | 98% |
| Hodgdon Superformance | <<locked>> | 80% | 55,970 psi | 80% | 2861 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,253 psi | 41% | 1588 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 57,957 psi | 83% | 2782 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,575 psi | 73% | 2707 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 56,594 psi | 81% | 2785 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 46,470 psi | 67% | 2641 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 44,034 psi | 63% | 2608 fps | 98.3% |
| IMR 7828 SSC | <<locked>> | 80% | 41,452 psi | 60% | 2654 fps | 98.3% |
| IMR 7977 Enduron | <<locked>> | 94% | 55,027 psi | 79% | 2762 fps | 95.3% |
| IMR 8133 Enduron | <<locked>> | 88% | 32,561 psi | 47% | 2487 fps | 95.9% |
| Lovex S065 | <<locked>> | 80% | 54,128 psi | 78% | 2733 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 52,692 psi | 76% | 2736 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 35,273 psi | 51% | 2434 fps | 99.4% |
| Norma 204 | <<locked>> | 80% | 51,329 psi | 74% | 2762 fps | 99.9% |
| Norma 217 | <<locked>> | 82% | 26,745 psi | 38% | 2343 fps | 95.4% |
| Norma MRP | <<locked>> | 80% | 43,207 psi | 62% | 2694 fps | 99.9% |
| Norma URP | <<locked>> | 80% | 52,475 psi | 75% | 2753 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 43,613 psi | 63% | 2710 fps | 99.1% |
| Ramshot Hunter | <<locked>> | 80% | 51,358 psi | 74% | 2762 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 38,218 psi | 55% | 2569 fps | 99.2% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,921 psi | 42% | 1624 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 54,157 psi | 78% | 2792 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 52,576 psi | 76% | 2818 fps | 100% |
| ReloadSwiss RS 76 | 91.9 gr | 80% | 32,518 psi | 47% | 2523 fps | 98.7% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 34,214 psi | 49% | 2543 fps | 95.1% |
| Rottweil R 904 | <<locked>> | 80% | 45,934 psi | 66% | 2648 fps | 99% |
| Rottweil R 905 | <<locked>> | 80% | 44,382 psi | 64% | 2657 fps | 99.5% |
| Rottweil R 907 | <<locked>> | 80% | 55,274 psi | 79% | 2766 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 54,128 psi | 78% | 2733 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 52,692 psi | 76% | 2736 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 53,084 psi | 76% | 2690 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 44,034 psi | 63% | 2651 fps | 99.5% |
| Somchem S361 | <<locked>> | 80% | 46,775 psi | 67% | 2638 fps | 98.7% |
| Somchem S365 | <<locked>> | 80% | 50,009 psi | 72% | 2703 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 44,831 psi | 64% | 2635 fps | 99.8% |
| Unknown powder | <<locked>> | 80% | 55,811 psi | 80% | 2799 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 51,909 psi | 75% | 2641 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 55,898 psi | 80% | 2766 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 38,043 psi | 55% | 2493 fps | 98.8% |
| Vihtavuori N170 | <<locked>> | 96% | 47,964 psi | 69% | 2707 fps | 95.5% |
| Vihtavuori N550 | <<locked>> | 80% | 56,550 psi | 81% | 2812 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 44,106 psi | 63% | 2638 fps | 100% |
| Vihtavuori N560 | <<locked>> | 80% | 40,901 psi | 59% | 2648 fps | 97.7% |
| Vihtavuori N565 | <<locked>> | 80% | 35,621 psi | 51% | 2516 fps | 96.4% |
| Vihtavuori N568 | <<locked>> | 86% | 38,203 psi | 55% | 2621 fps | 96% |
| Vihtavuori N570 | <<locked>> | 90% | 42,061 psi | 60% | 2733 fps | 95.2% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 53,084 psi | 76% | 2690 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 37,130 psi | 53% | 2625 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 44,817 psi | 64% | 2635 fps | 99.5% |
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 | RWS Speed Tip Professional. Hodgdon Retumbo delivers the highest muzzle velocity at 3,077 fps; across all powders the maximum-charge window runs from 1,775 fps to 3,077 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 1:12.0 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, ReloadSwiss RS 76, Accurate MAGPRO rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 250gr | RWS Speed Tip Professional 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.