Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 185gr | Barnes MRX BT bullet and 104 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Norma MRP, Alliant Reloder-26 and Ramshot Grand.
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 2495 | <<locked>> | 82% | 61,264 psi | 88% | 3127 fps | 100% |
| Accurate 2700 | <<locked>> | 86% | 60,278 psi | 87% | 3182 fps | 99.8% |
| Accurate 3100 | <<locked>> | 98% | 59,074 psi | 85% | 3232 fps | 100% |
| Accurate 4064 | <<locked>> | 84% | 61,888 psi | 89% | 3192 fps | 100% |
| Accurate 4350 | <<locked>> | 90% | 60,524 psi | 87% | 3281 fps | 100% |
| Accurate MAGPRO | <<locked>> | 98% | 58,972 psi | 85% | 3346 fps | 97.6% |
| ADI APS 450 | <<locked>> | 84% | 62,845 psi | 90% | 2566 fps | 100% |
| ADI AR 2208 | <<locked>> | 86% | 61,598 psi | 88% | 3241 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 61,786 psi | 89% | 3343 fps | 99.7% |
| ADI AR 2213 | <<locked>> | 98% | 59,582 psi | 86% | 3350 fps | 99% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 46,238 psi | 66% | 3087 fps | 96.8% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 41,017 psi | 59% | 3038 fps | 98.5% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 59,132 psi | 85% | 3209 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 59,190 psi | 85% | 3235 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 92% | 61,540 psi | 88% | 3343 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 59,030 psi | 85% | 3304 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 96% | 61,017 psi | 88% | 3327 fps | 99.7% |
| Alliant Reloder-22 | <<locked>> | 98% | 59,190 psi | 85% | 3340 fps | 99.7% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 60,075 psi | 86% | 3297 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 51,938 psi | 75% | 3245 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 96% | 61,525 psi | 88% | 3409 fps | 100% |
| Baschieri & Pellagri 109ᴾ | <<locked>> | 100% | 61,612 psi | 89% | 3297 fps | 97% |
| Bofors RP15ᴾ | <<locked>> | 100% | 57,885 psi | 83% | 3317 fps | 99.5% |
| Bofors RP3 | <<locked>> | 84% | 60,365 psi | 87% | 3228 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 47,819 psi | 69% | 3166 fps | 97.6% |
| Bofors RP5 | <<locked>> | 98% | 59,190 psi | 85% | 3340 fps | 99.7% |
| Bofors RP7 | <<locked>> | 88% | 59,263 psi | 85% | 3225 fps | 99.8% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 47,529 psi | 68% | 3120 fps | 97.8% |
| Hodgdon H380 | <<locked>> | 84% | 60,568 psi | 87% | 3255 fps | 100% |
| Hodgdon H414 | <<locked>> | 86% | 59,959 psi | 86% | 3301 fps | 100% |
| Hodgdon H4350 | <<locked>> | 90% | 59,799 psi | 86% | 3271 fps | 99.7% |
| Hodgdon H4831ᴾ | <<locked>> | 100% | 58,494 psi | 84% | 3264 fps | 98.3% |
| Hodgdon H4831 SC | <<locked>> | 98% | 62,468 psi | 90% | 3323 fps | 98.8% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 61,670 psi | 89% | 3245 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 84% | 62,685 psi | 90% | 3287 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 50,821 psi | 73% | 3307 fps | 99.5% |
| Hodgdon Superformance | <<locked>> | 88% | 59,727 psi | 86% | 3323 fps | 100% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,637 psi | 53% | 2041 fps | 100% |
| Hodgdon VARGET | <<locked>> | 84% | 61,076 psi | 88% | 3228 fps | 100% |
| IMR 3031 | <<locked>> | 82% | 60,640 psi | 87% | 3189 fps | 100% |
| IMR 4064 | <<locked>> | 86% | 60,452 psi | 87% | 3212 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 88% | 62,540 psi | 90% | 3255 fps | 100% |
| IMR 4350 | <<locked>> | 92% | 61,163 psi | 88% | 3264 fps | 99.9% |
| IMR 4451 Enduron | <<locked>> | 88% | 61,090 psi | 88% | 3255 fps | 100% |
| IMR 4831 | <<locked>> | 96% | 61,844 psi | 89% | 3278 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 60,756 psi | 87% | 3264 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 96% | 60,292 psi | 87% | 3258 fps | 98.7% |
| IMR 7828 SSC | <<locked>> | 98% | 61,627 psi | 89% | 3389 fps | 99.3% |
| Lovex S060 | <<locked>> | 82% | 62,004 psi | 89% | 3199 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 61,235 psi | 88% | 3209 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 61,438 psi | 88% | 3245 fps | 100% |
| Lovex S070 | <<locked>> | 90% | 59,335 psi | 85% | 3238 fps | 100% |
| Lovex S071ᴾ | <<locked>> | 100% | 52,359 psi | 75% | 3130 fps | 99.9% |
| Norma 201 | <<locked>> | 82% | 62,381 psi | 90% | 3219 fps | 100% |
| Norma 203B | <<locked>> | 84% | 62,395 psi | 90% | 3274 fps | 100% |
| Norma 204 | <<locked>> | 92% | 62,830 psi | 90% | 3333 fps | 99.7% |
| Norma 217ᴾ | <<locked>> | 100% | 36,274 psi | 52% | 2943 fps | 96.2% |
| Norma MRP | <<locked>> | 96% | 59,190 psi | 85% | 3366 fps | 100% |
| Norma URP | <<locked>> | 92% | 62,772 psi | 90% | 3317 fps | 100% |
| Ramshot Big Game | <<locked>> | 82% | 60,046 psi | 86% | 3248 fps | 100% |
| Ramshot Grand | <<locked>> | 96% | 62,120 psi | 89% | 3406 fps | 99.5% |
| Ramshot Hunter | <<locked>> | 92% | 61,844 psi | 89% | 3327 fps | 100% |
| Ramshot Magnum | <<locked>> | 98% | 58,885 psi | 85% | 3301 fps | 99.9% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,463 psi | 54% | 2090 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 60,321 psi | 87% | 3238 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 62,990 psi | 90% | 3346 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 90% | 60,756 psi | 87% | 3301 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 59,495 psi | 85% | 3340 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 51,663 psi | 74% | 3307 fps | 100% |
| Rottweil R 902 | <<locked>> | 82% | 59,321 psi | 85% | 3166 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 60,582 psi | 87% | 3225 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 62,990 psi | 90% | 3307 fps | 99.3% |
| Rottweil R 905 | <<locked>> | 96% | 60,481 psi | 87% | 3314 fps | 99.7% |
| Rottweil R 907 | <<locked>> | 88% | 59,263 psi | 85% | 3225 fps | 99.8% |
| Shooters World Long Rifle | <<locked>> | 90% | 61,438 psi | 88% | 3245 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 61,235 psi | 88% | 3209 fps | 100% |
| Shooters World SW4350 | <<locked>> | 90% | 59,335 psi | 85% | 3238 fps | 100% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 62,671 psi | 90% | 3291 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 62,772 psi | 90% | 3258 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 62,627 psi | 90% | 3133 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 60,611 psi | 87% | 3084 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 61,061 psi | 88% | 3196 fps | 100% |
| SNPE Vectan Tubal 8000 | <<locked>> | 96% | 60,002 psi | 86% | 3310 fps | 99.7% |
| Somchem S335 | <<locked>> | 82% | 62,540 psi | 90% | 3127 fps | 100% |
| Somchem S355 | <<locked>> | 86% | 60,191 psi | 86% | 3219 fps | 100% |
| Somchem S361 | <<locked>> | 94% | 61,250 psi | 88% | 3238 fps | 98.6% |
| Somchem S365 | <<locked>> | 92% | 59,263 psi | 85% | 3261 fps | 100% |
| Somchem S385 | <<locked>> | 96% | 61,076 psi | 88% | 3281 fps | 99.9% |
| Unknown powder | <<locked>> | 88% | 59,146 psi | 85% | 3268 fps | 100% |
| Vihtavuori N133 | <<locked>> | 84% | 62,830 psi | 90% | 3104 fps | 100% |
| Vihtavuori N135 | <<locked>> | 82% | 60,031 psi | 86% | 3114 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 59,495 psi | 85% | 3127 fps | 100% |
| Vihtavuori N150 | <<locked>> | 92% | 62,149 psi | 89% | 3192 fps | 100% |
| Vihtavuori N160 | <<locked>> | 88% | 59,640 psi | 86% | 3228 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 58,465 psi | 84% | 3222 fps | 99.7% |
| Vihtavuori N540 | <<locked>> | 82% | 59,234 psi | 85% | 3153 fps | 100% |
| Vihtavuori N550 | <<locked>> | 88% | 60,089 psi | 86% | 3281 fps | 100% |
| Vihtavuori N555 | <<locked>> | 98% | 62,352 psi | 90% | 3330 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 59,640 psi | 86% | 3373 fps | 98.8% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 54,549 psi | 78% | 3258 fps | 98.2% |
| Winchester 6.5 StaBALL | <<locked>> | 90% | 61,032 psi | 88% | 3202 fps | 100% |
| Winchester 760 | <<locked>> | 86% | 59,959 psi | 86% | 3301 fps | 100% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 58,001 psi | 83% | 3392 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 94% | 59,205 psi | 85% | 3245 fps | 99.5% |
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 2495 | <<locked>> | 80% | 57,246 psi | 82% | 3074 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 49,371 psi | 71% | 3005 fps | 98.8% |
| Accurate 3100 | <<locked>> | 80% | 31,227 psi | 45% | 2677 fps | 95.5% |
| Accurate 4064 | <<locked>> | 80% | 54,360 psi | 78% | 3087 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 42,467 psi | 61% | 2972 fps | 99.7% |
| Accurate MAGPRO | <<locked>> | 94% | 50,894 psi | 73% | 3205 fps | 95.9% |
| ADI APS 450 | <<locked>> | 80% | 58,769 psi | 84% | 2503 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 50,995 psi | 73% | 3077 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 38,218 psi | 55% | 2894 fps | 95.2% |
| ADI AR 2213 | <<locked>> | 88% | 42,003 psi | 60% | 3009 fps | 95.1% |
| ADI AR 2217 | <<locked>> | 98% | 43,120 psi | 62% | 3022 fps | 95.8% |
| ADI AR 2225 | <<locked>> | 94% | 33,547 psi | 48% | 2835 fps | 95.4% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 52,025 psi | 75% | 3100 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 55,463 psi | 80% | 3179 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 40,973 psi | 59% | 2986 fps | 99.8% |
| Alliant Reloder-17 | <<locked>> | 80% | 47,442 psi | 68% | 3120 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 82% | 38,174 psi | 55% | 2887 fps | 95.3% |
| Alliant Reloder-22 | <<locked>> | 86% | 38,841 psi | 56% | 2943 fps | 95.7% |
| Alliant Reloder-23 | <<locked>> | 80% | 30,153 psi | 43% | 2717 fps | 98.6% |
| Alliant Reloder-25 | <<locked>> | 84% | 30,124 psi | 43% | 2730 fps | 95.6% |
| Alliant Reloder-26 | 94.5 gr | 80% | 32,866 psi | 47% | 2851 fps | 97.7% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 54,172 psi | 78% | 3169 fps | 95.3% |
| Bofors RP15 | <<locked>> | 88% | 38,566 psi | 55% | 2936 fps | 95.4% |
| Bofors RP3 | <<locked>> | 80% | 52,794 psi | 76% | 3114 fps | 100% |
| Bofors RP30 | <<locked>> | 96% | 41,452 psi | 60% | 3031 fps | 95.8% |
| Bofors RP5 | <<locked>> | 86% | 38,841 psi | 56% | 2943 fps | 95.7% |
| Bofors RP7 | <<locked>> | 80% | 45,803 psi | 66% | 2986 fps | 98.3% |
| Hodgdon H1000 | <<locked>> | 96% | 41,452 psi | 60% | 2989 fps | 95.9% |
| Hodgdon H380 | <<locked>> | 80% | 52,895 psi | 76% | 3133 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 48,530 psi | 70% | 3107 fps | 99.2% |
| Hodgdon H4350 | <<locked>> | 80% | 43,279 psi | 62% | 2969 fps | 97.1% |
| Hodgdon H4831 | <<locked>> | 92% | 44,817 psi | 64% | 3015 fps | 95.3% |
| Hodgdon H4831 SC | <<locked>> | 88% | 44,106 psi | 63% | 2999 fps | 95.1% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 38,566 psi | 55% | 2864 fps | 99.9% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 54,824 psi | 79% | 3176 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 90% | 36,114 psi | 52% | 2949 fps | 95.1% |
| Hodgdon Superformance | <<locked>> | 80% | 44,077 psi | 63% | 3048 fps | 98.3% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,340 psi | 39% | 1831 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 53,925 psi | 77% | 3123 fps | 100% |
| IMR 3031 | <<locked>> | 80% | 56,971 psi | 82% | 3140 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 50,169 psi | 72% | 3054 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 48,878 psi | 70% | 3028 fps | 99.2% |
| IMR 4350 | <<locked>> | 80% | 41,350 psi | 59% | 2907 fps | 97.4% |
| IMR 4451 Enduron | <<locked>> | 80% | 47,369 psi | 68% | 3018 fps | 98.9% |
| IMR 4831 | <<locked>> | 80% | 36,767 psi | 53% | 2831 fps | 98.9% |
| IMR 4895 | <<locked>> | 80% | 56,913 psi | 82% | 3209 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 86% | 43,700 psi | 63% | 2956 fps | 95.2% |
| IMR 7828 SSC | <<locked>> | 88% | 43,004 psi | 62% | 3045 fps | 95.5% |
| Lovex S060 | <<locked>> | 80% | 58,175 psi | 84% | 3143 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 53,940 psi | 77% | 3100 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 44,672 psi | 64% | 2963 fps | 99.3% |
| Lovex S070 | <<locked>> | 80% | 43,004 psi | 62% | 2946 fps | 98.4% |
| Lovex S071 | <<locked>> | 84% | 30,618 psi | 44% | 2661 fps | 95.2% |
| Norma 201 | <<locked>> | 80% | 58,450 psi | 84% | 3163 fps | 100% |
| Norma 203B | <<locked>> | 80% | 54,795 psi | 79% | 3163 fps | 100% |
| Norma 204 | <<locked>> | 80% | 41,263 psi | 59% | 2943 fps | 96.1% |
| Norma 217 | <<locked>> | 98% | 33,910 psi | 49% | 2877 fps | 95.1% |
| Norma MRP | 94 gr | 82% | 35,331 psi | 51% | 2887 fps | 95.9% |
| Norma URP | <<locked>> | 80% | 42,047 psi | 60% | 2966 fps | 99.6% |
| Ramshot Big Game | <<locked>> | 80% | 56,057 psi | 81% | 3189 fps | 100% |
| Ramshot Grand | 101.7 gr | 86% | 41,989 psi | 60% | 3031 fps | 95.6% |
| Ramshot Hunter | <<locked>> | 80% | 40,973 psi | 59% | 2956 fps | 98.5% |
| Ramshot Magnum | <<locked>> | 86% | 36,390 psi | 52% | 2867 fps | 95.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,905 psi | 40% | 1873 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 52,881 psi | 76% | 3120 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 50,430 psi | 72% | 3169 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 42,569 psi | 61% | 2995 fps | 99.6% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 41,118 psi | 59% | 3012 fps | 99.4% |
| ReloadSwiss RS 76 | <<locked>> | 90% | 35,433 psi | 51% | 2927 fps | 96.3% |
| Rottweil R 902 | <<locked>> | 80% | 55,738 psi | 80% | 3117 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 49,632 psi | 71% | 3058 fps | 100% |
| Rottweil R 904 | <<locked>> | 84% | 42,438 psi | 61% | 2936 fps | 95.4% |
| Rottweil R 905 | <<locked>> | 82% | 37,289 psi | 54% | 2867 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 45,803 psi | 66% | 2986 fps | 98.3% |
| Shooters World Long Rifle | <<locked>> | 80% | 44,672 psi | 64% | 2963 fps | 99.3% |
| Shooters World Precision | <<locked>> | 80% | 53,940 psi | 77% | 3100 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 43,004 psi | 62% | 2946 fps | 98.4% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 51,198 psi | 74% | 3120 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 58,726 psi | 84% | 3199 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 58,827 psi | 85% | 3081 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 50,096 psi | 72% | 2936 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 43,758 psi | 63% | 2900 fps | 98.4% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 36,956 psi | 53% | 2861 fps | 95% |
| Somchem S335 | <<locked>> | 80% | 58,697 psi | 84% | 3077 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 49,574 psi | 71% | 3054 fps | 100% |
| Somchem S361 | <<locked>> | 86% | 46,543 psi | 67% | 2986 fps | 95.8% |
| Somchem S365 | <<locked>> | 80% | 38,711 psi | 56% | 2917 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 35,404 psi | 51% | 2789 fps | 95.4% |
| Unknown powder | <<locked>> | 80% | 45,150 psi | 65% | 3028 fps | 99.7% |
| Vihtavuori N133 | <<locked>> | 80% | 55,796 psi | 80% | 3012 fps | 100% |
| Vihtavuori N135 | <<locked>> | 80% | 56,304 psi | 81% | 3064 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 55,753 psi | 80% | 3071 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 42,569 psi | 61% | 2887 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 45,281 psi | 65% | 2992 fps | 99.9% |
| Vihtavuori N165 | <<locked>> | 86% | 36,419 psi | 52% | 2802 fps | 95.4% |
| Vihtavuori N540 | <<locked>> | 80% | 55,564 psi | 80% | 3100 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 45,861 psi | 66% | 3041 fps | 99.9% |
| Vihtavuori N555 | <<locked>> | 80% | 33,736 psi | 48% | 2799 fps | 98.6% |
| Vihtavuori N560 | <<locked>> | 90% | 45,005 psi | 65% | 3100 fps | 95.7% |
| Vihtavuori N565 | <<locked>> | 94% | 44,048 psi | 63% | 3058 fps | 95.7% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 42,728 psi | 61% | 2920 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 48,530 psi | 70% | 3107 fps | 99.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 26,658 psi | 38% | 2703 fps | 98.3% |
| Winchester Supreme 780 | <<locked>> | 82% | 37,985 psi | 55% | 2848 fps | 95.3% |
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 109 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 185gr | Barnes MRX BT. Alliant Reloder-26 delivers the highest muzzle velocity at 3,409 fps; across all powders the maximum-charge window runs from 2,041 fps to 3,409 fps. ADI AR 2217 gives the best case fill at 100 %, and 109 of the 109 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (480 MPa), the top charges use 52–90 %, leaving at least 10 % headroom. The 185.0 gr projectile in 0.338" calls for a 1:13.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Alliant Reloder-23 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. Norma MRP, Alliant Reloder-26, Ramshot Grand rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 185gr | Barnes MRX BT they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, IMR 7977 Enduron, IMR 8133 Enduron, Vihtavuori N570 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.