Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 275gr | Peregrine Glider GRM bullet and 79 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 N560.
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% | 62,656 psi | 90% | 2687 fps | 100% |
| Accurate 3100 | <<locked>> | 92% | 60,017 psi | 86% | 2707 fps | 100% |
| Accurate 4350 | <<locked>> | 84% | 61,003 psi | 88% | 2723 fps | 100% |
| Accurate MAGPRO | <<locked>> | 92% | 60,031 psi | 86% | 2841 fps | 99.9% |
| ADI APS 450 | <<locked>> | 82% | 61,351 psi | 88% | 2087 fps | 100% |
| ADI AR 2209 | <<locked>> | 90% | 62,062 psi | 89% | 2802 fps | 100% |
| ADI AR 2213 | <<locked>> | 92% | 60,249 psi | 87% | 2825 fps | 100% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 58,392 psi | 84% | 2799 fps | 100% |
| ADI AR 2218ᴾ | <<locked>> | 100% | 50,444 psi | 72% | 2799 fps | 98.6% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 52,562 psi | 76% | 2766 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 86% | 62,294 psi | 89% | 2772 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 90% | 61,351 psi | 88% | 2792 fps | 100% |
| Alliant Reloder-22 | <<locked>> | 92% | 60,321 psi | 87% | 2812 fps | 100% |
| Alliant Reloder-23 | <<locked>> | 94% | 62,076 psi | 89% | 2759 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 98% | 62,178 psi | 89% | 2835 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 88% | 58,929 psi | 85% | 2808 fps | 100% |
| Alliant Reloder-33ᴾ | <<locked>> | 100% | 55,550 psi | 80% | 2844 fps | 99.2% |
| Alliant Reloder-50ᴾ | <<locked>> | 100% | 46,499 psi | 67% | 2700 fps | 97.2% |
| Baschieri & Pellagri 109 | <<locked>> | 94% | 60,800 psi | 87% | 2789 fps | 99.6% |
| Bofors RP15 | <<locked>> | 94% | 59,437 psi | 85% | 2802 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 61,844 psi | 89% | 2864 fps | 100% |
| Bofors RP5 | <<locked>> | 92% | 60,321 psi | 87% | 2812 fps | 100% |
| Bofors RP7 | <<locked>> | 84% | 62,062 psi | 89% | 2723 fps | 100% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 60,104 psi | 86% | 2818 fps | 100% |
| Hodgdon H4350 | <<locked>> | 84% | 59,393 psi | 85% | 2723 fps | 100% |
| Hodgdon H4831 | <<locked>> | 96% | 62,932 psi | 90% | 2802 fps | 100% |
| Hodgdon H4831 SC | <<locked>> | 92% | 62,323 psi | 90% | 2795 fps | 100% |
| Hodgdon Hybrid 100V | <<locked>> | 88% | 62,250 psi | 89% | 2690 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 98% | 61,351 psi | 88% | 2930 fps | 100% |
| Hodgdon Superformance | <<locked>> | 82% | 59,524 psi | 86% | 2776 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,463 psi | 54% | 1670 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 61,192 psi | 88% | 2687 fps | 100% |
| IMR 4350 | <<locked>> | 86% | 60,582 psi | 87% | 2717 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 82% | 59,814 psi | 86% | 2694 fps | 100% |
| IMR 4831 | <<locked>> | 90% | 62,685 psi | 90% | 2730 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 90% | 59,814 psi | 86% | 2733 fps | 100% |
| IMR 7828 SSC | <<locked>> | 92% | 62,714 psi | 90% | 2861 fps | 100% |
| IMR 7977 Enduron | <<locked>> | 98% | 62,178 psi | 89% | 2740 fps | 97.4% |
| IMR 8133 Enduronᴾ | <<locked>> | 100% | 48,037 psi | 69% | 2694 fps | 99.9% |
| Lovex S065 | <<locked>> | 84% | 60,597 psi | 87% | 2687 fps | 100% |
| Lovex S070 | <<locked>> | 86% | 62,917 psi | 90% | 2740 fps | 100% |
| Lovex S071 | <<locked>> | 98% | 61,467 psi | 88% | 2723 fps | 100% |
| Norma 204 | <<locked>> | 86% | 62,236 psi | 89% | 2782 fps | 100% |
| Norma 217ᴾ | <<locked>> | 100% | 48,631 psi | 70% | 2710 fps | 100% |
| Norma MRP | <<locked>> | 90% | 60,539 psi | 87% | 2828 fps | 100% |
| Norma URP | <<locked>> | 84% | 59,103 psi | 85% | 2707 fps | 100% |
| Ramshot Grand | <<locked>> | 88% | 58,668 psi | 84% | 2815 fps | 100% |
| Ramshot Hunter | <<locked>> | 86% | 61,931 psi | 89% | 2769 fps | 100% |
| Ramshot Magnum | <<locked>> | 92% | 59,988 psi | 86% | 2782 fps | 100% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,450 psi | 55% | 1713 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 84% | 61,250 psi | 88% | 2749 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 84% | 60,104 psi | 86% | 2782 fps | 100% |
| ReloadSwiss RS 76 | <<locked>> | 98% | 62,497 psi | 90% | 2923 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 61,627 psi | 89% | 2907 fps | 100% |
| Rottweil R 904 | <<locked>> | 90% | 62,584 psi | 90% | 2769 fps | 100% |
| Rottweil R 905 | <<locked>> | 90% | 61,105 psi | 88% | 2782 fps | 100% |
| Rottweil R 907 | <<locked>> | 84% | 62,062 psi | 89% | 2723 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 84% | 60,597 psi | 87% | 2687 fps | 100% |
| Shooters World SW4350 | <<locked>> | 86% | 62,917 psi | 90% | 2740 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 82% | 62,700 psi | 90% | 2559 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 84% | 59,770 psi | 86% | 2651 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 90% | 60,684 psi | 87% | 2779 fps | 100% |
| Somchem S361 | <<locked>> | 88% | 60,321 psi | 87% | 2717 fps | 100% |
| Somchem S365 | <<locked>> | 86% | 60,394 psi | 87% | 2703 fps | 100% |
| Somchem S385 | <<locked>> | 90% | 61,366 psi | 88% | 2746 fps | 100% |
| Unknown powder | <<locked>> | 82% | 59,117 psi | 85% | 2710 fps | 100% |
| Vihtavuori N150 | <<locked>> | 86% | 61,656 psi | 89% | 2631 fps | 100% |
| Vihtavuori N160 | <<locked>> | 82% | 59,364 psi | 85% | 2674 fps | 100% |
| Vihtavuori N165 | <<locked>> | 94% | 59,234 psi | 85% | 2710 fps | 100% |
| Vihtavuori N170ᴾ | <<locked>> | 100% | 53,838 psi | 77% | 2687 fps | 97.5% |
| Vihtavuori N550 | <<locked>> | 82% | 59,901 psi | 86% | 2720 fps | 100% |
| Vihtavuori N555 | <<locked>> | 90% | 60,017 psi | 86% | 2736 fps | 100% |
| Vihtavuori N560 | <<locked>> | 92% | 60,800 psi | 87% | 2851 fps | 100% |
| Vihtavuori N565 | <<locked>> | 96% | 60,423 psi | 87% | 2828 fps | 100% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 62,062 psi | 89% | 2900 fps | 100% |
| Vihtavuori N570ᴾ | <<locked>> | 100% | 59,495 psi | 85% | 2910 fps | 99.4% |
| Winchester 6.5 StaBALL | <<locked>> | 84% | 60,292 psi | 87% | 2651 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 94% | 62,163 psi | 89% | 2854 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 88% | 58,871 psi | 85% | 2720 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% | 58,682 psi | 84% | 2638 fps | 100% |
| Accurate 3100 | <<locked>> | 80% | 40,045 psi | 58% | 2421 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 53,301 psi | 77% | 2628 fps | 100% |
| Accurate MAGPRO | <<locked>> | 80% | 39,204 psi | 56% | 2497 fps | 96.8% |
| ADI APS 450 | <<locked>> | 80% | 59,248 psi | 85% | 2057 fps | 100% |
| ADI AR 2209 | <<locked>> | 80% | 44,396 psi | 64% | 2543 fps | 99.8% |
| ADI AR 2213 | <<locked>> | 80% | 39,624 psi | 57% | 2493 fps | 98.5% |
| ADI AR 2217 | <<locked>> | 80% | 29,370 psi | 42% | 2254 fps | 95.1% |
| ADI AR 2218 | <<locked>> | 94% | 40,567 psi | 58% | 2598 fps | 95.7% |
| ADI AR 2225 | <<locked>> | 80% | 26,672 psi | 38% | 2228 fps | 97.1% |
| Alliant Reloder-16 | <<locked>> | 80% | 51,329 psi | 74% | 2635 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 44,396 psi | 64% | 2539 fps | 99.8% |
| Alliant Reloder-22 | <<locked>> | 80% | 40,176 psi | 58% | 2497 fps | 99.4% |
| Alliant Reloder-23 | <<locked>> | 80% | 38,972 psi | 56% | 2438 fps | 100% |
| Alliant Reloder-25 | <<locked>> | 80% | 33,518 psi | 48% | 2385 fps | 99.9% |
| Alliant Reloder-26 | <<locked>> | 80% | 43,685 psi | 63% | 2592 fps | 100% |
| Alliant Reloder-33 | <<locked>> | 90% | 38,058 psi | 55% | 2533 fps | 95.1% |
| Alliant Reloder-50 | <<locked>> | 96% | 39,958 psi | 57% | 2575 fps | 95.3% |
| Baschieri & Pellagri 109 | <<locked>> | 80% | 38,899 psi | 56% | 2418 fps | 95.4% |
| Bofors RP15 | <<locked>> | 80% | 37,405 psi | 54% | 2441 fps | 98.8% |
| Bofors RP30 | <<locked>> | 80% | 30,980 psi | 45% | 2326 fps | 96.4% |
| Bofors RP5 | <<locked>> | 80% | 40,176 psi | 58% | 2497 fps | 99.4% |
| Bofors RP7 | <<locked>> | 80% | 54,824 psi | 79% | 2628 fps | 100% |
| Hodgdon H1000 | <<locked>> | 80% | 30,168 psi | 43% | 2277 fps | 96.2% |
| Hodgdon H4350 | <<locked>> | 80% | 52,417 psi | 75% | 2628 fps | 100% |
| Hodgdon H4831 | <<locked>> | 80% | 37,318 psi | 54% | 2392 fps | 97.2% |
| Hodgdon H4831 SC | <<locked>> | 80% | 41,481 psi | 60% | 2477 fps | 98.3% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 48,008 psi | 69% | 2513 fps | 100% |
| Hodgdon Retumbo | 80.8 gr | 80% | 32,764 psi | 47% | 2428 fps | 98.6% |
| Hodgdon Superformance | <<locked>> | 80% | 55,347 psi | 80% | 2720 fps | 100% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,166 psi | 40% | 1493 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 57,638 psi | 83% | 2641 fps | 100% |
| IMR 4350 | <<locked>> | 80% | 50,125 psi | 72% | 2575 fps | 100% |
| IMR 4451 Enduron | <<locked>> | 80% | 56,188 psi | 81% | 2644 fps | 100% |
| IMR 4831 | <<locked>> | 80% | 45,818 psi | 66% | 2507 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 80% | 43,540 psi | 63% | 2484 fps | 98.8% |
| IMR 7828 SSC | <<locked>> | 80% | 40,857 psi | 59% | 2526 fps | 98.8% |
| IMR 7977 Enduron | <<locked>> | 92% | 51,169 psi | 74% | 2582 fps | 95.2% |
| IMR 8133 Enduron | <<locked>> | 86% | 29,631 psi | 43% | 2313 fps | 95.5% |
| Lovex S065 | <<locked>> | 80% | 53,592 psi | 77% | 2595 fps | 100% |
| Lovex S070 | <<locked>> | 80% | 52,054 psi | 75% | 2598 fps | 100% |
| Lovex S071 | <<locked>> | 80% | 34,403 psi | 49% | 2310 fps | 99.7% |
| Norma 204 | <<locked>> | 80% | 50,807 psi | 73% | 2628 fps | 100% |
| Norma 217 | <<locked>> | 82% | 25,846 psi | 37% | 2224 fps | 96% |
| Norma MRP | <<locked>> | 80% | 42,598 psi | 61% | 2562 fps | 100% |
| Norma URP | <<locked>> | 80% | 51,895 psi | 75% | 2612 fps | 100% |
| Ramshot Grand | <<locked>> | 80% | 43,018 psi | 62% | 2579 fps | 99.4% |
| Ramshot Hunter | <<locked>> | 80% | 50,792 psi | 73% | 2625 fps | 100% |
| Ramshot Magnum | <<locked>> | 80% | 37,434 psi | 54% | 2444 fps | 99.5% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,834 psi | 41% | 1529 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 53,447 psi | 77% | 2651 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 51,996 psi | 75% | 2680 fps | 100% |
| ReloadSwiss RS 76 | 86.5 gr | 80% | 31,749 psi | 46% | 2405 fps | 99.1% |
| ReloadSwiss RS 80 | <<locked>> | 84% | 33,243 psi | 48% | 2418 fps | 95.7% |
| Rottweil R 904 | <<locked>> | 80% | 45,353 psi | 65% | 2520 fps | 99.4% |
| Rottweil R 905 | <<locked>> | 80% | 43,903 psi | 63% | 2530 fps | 99.8% |
| Rottweil R 907 | <<locked>> | 80% | 54,824 psi | 79% | 2628 fps | 100% |
| Shooters World Long Rifle | <<locked>> | 80% | 53,592 psi | 77% | 2595 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 52,054 psi | 75% | 2598 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 59,016 psi | 85% | 2520 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 52,388 psi | 75% | 2552 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 80% | 43,569 psi | 63% | 2526 fps | 99.7% |
| Somchem S361 | <<locked>> | 80% | 46,122 psi | 66% | 2510 fps | 99% |
| Somchem S365 | <<locked>> | 80% | 49,385 psi | 71% | 2569 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 44,135 psi | 63% | 2503 fps | 100% |
| Unknown powder | <<locked>> | 80% | 55,405 psi | 80% | 2661 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 51,271 psi | 74% | 2503 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 55,463 psi | 80% | 2628 fps | 100% |
| Vihtavuori N165 | <<locked>> | 80% | 37,391 psi | 54% | 2372 fps | 99.2% |
| Vihtavuori N170 | <<locked>> | 94% | 44,309 psi | 64% | 2530 fps | 95.3% |
| Vihtavuori N550 | <<locked>> | 80% | 56,057 psi | 81% | 2671 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 43,352 psi | 62% | 2507 fps | 100% |
| Vihtavuori N560 | 82.1 gr | 80% | 40,350 psi | 58% | 2523 fps | 98.3% |
| Vihtavuori N565 | <<locked>> | 80% | 34,766 psi | 50% | 2392 fps | 96.9% |
| Vihtavuori N568 | <<locked>> | 84% | 34,795 psi | 50% | 2438 fps | 95.6% |
| Vihtavuori N570 | <<locked>> | 90% | 41,220 psi | 59% | 2605 fps | 95.8% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 52,605 psi | 76% | 2559 fps | 100% |
| Winchester StaBALL HD | <<locked>> | 80% | 36,419 psi | 52% | 2493 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 80% | 44,208 psi | 64% | 2507 fps | 99.7% |
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 86 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 275gr | Peregrine Glider GRM. Hodgdon Retumbo delivers the highest muzzle velocity at 2,930 fps; across all powders the maximum-charge window runs from 1,670 fps to 2,930 fps. Accurate 8700 gives the best case fill at 100 %, and 86 of the 86 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 275.0 gr projectile in 0.338" calls for a 1:9.5 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, Vihtavuori N560 rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 275gr | Peregrine Glider GRM they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Accurate 8700, Ramshot LRT, Vihtavuori 20N29 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.