Load Specifications
Load data in caliber .338 Lapua Mag. Ackley Improved with .338 | 175gr | Barnes X S bullet and 94 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are IMR 7828 SSC, Vihtavuori N560 and Norma MRP.
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>> | 84% | 59,799 psi | 86% | 3235 fps | 99.7% |
| Accurate 3100 | <<locked>> | 96% | 60,263 psi | 87% | 3304 fps | 100% |
| Accurate 4350 | <<locked>> | 88% | 61,293 psi | 88% | 3350 fps | 100% |
| Accurate MAGPRO | <<locked>> | 96% | 58,987 psi | 85% | 3402 fps | 97.2% |
| ADI APS 450 | <<locked>> | 84% | 62,932 psi | 90% | 2638 fps | 100% |
| ADI AR 2208 | <<locked>> | 84% | 60,814 psi | 87% | 3294 fps | 100% |
| ADI AR 2209 | <<locked>> | 94% | 60,974 psi | 88% | 3392 fps | 99.5% |
| ADI AR 2213 | <<locked>> | 98% | 62,961 psi | 90% | 3461 fps | 99.1% |
| ADI AR 2217ᴾ | <<locked>> | 100% | 49,850 psi | 72% | 3212 fps | 97.2% |
| ADI AR 2225ᴾ | <<locked>> | 100% | 45,005 psi | 65% | 3179 fps | 99% |
| Alliant Reloder- TS 15.5 | <<locked>> | 84% | 62,816 psi | 90% | 3323 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 82% | 62,845 psi | 90% | 3350 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 90% | 60,829 psi | 87% | 3396 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 86% | 62,859 psi | 90% | 3419 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 94% | 60,524 psi | 87% | 3379 fps | 99.5% |
| Alliant Reloder-22 | <<locked>> | 96% | 59,074 psi | 85% | 3396 fps | 99.5% |
| Alliant Reloder-23 | <<locked>> | 98% | 60,220 psi | 87% | 3363 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 55,753 psi | 80% | 3369 fps | 100% |
| Alliant Reloder-26 | <<locked>> | 94% | 61,482 psi | 88% | 3471 fps | 100% |
| Baschieri & Pellagri 109 | <<locked>> | 98% | 60,611 psi | 87% | 3337 fps | 96.3% |
| Bofors RP15ᴾ | <<locked>> | 100% | 61,743 psi | 89% | 3438 fps | 99.6% |
| Bofors RP3 | <<locked>> | 82% | 60,901 psi | 87% | 3294 fps | 100% |
| Bofors RP30ᴾ | <<locked>> | 100% | 52,272 psi | 75% | 3304 fps | 98.1% |
| Bofors RP5 | <<locked>> | 96% | 59,074 psi | 85% | 3396 fps | 99.5% |
| Bofors RP7 | <<locked>> | 88% | 62,859 psi | 90% | 3340 fps | 99.9% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 51,169 psi | 74% | 3241 fps | 98.1% |
| Hodgdon H380 | <<locked>> | 82% | 60,568 psi | 87% | 3314 fps | 100% |
| Hodgdon H414 | <<locked>> | 84% | 59,379 psi | 85% | 3353 fps | 99.9% |
| Hodgdon H4350 | <<locked>> | 90% | 62,845 psi | 90% | 3379 fps | 99.7% |
| Hodgdon H4831ᴾ | <<locked>> | 100% | 61,917 psi | 89% | 3373 fps | 98.4% |
| Hodgdon H4831 SC | <<locked>> | 96% | 61,569 psi | 88% | 3369 fps | 98.4% |
| Hodgdon Hybrid 100V | <<locked>> | 92% | 61,496 psi | 88% | 3307 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 62,192 psi | 89% | 3343 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 54,795 psi | 79% | 3442 fps | 99.7% |
| Hodgdon Superformance | <<locked>> | 86% | 58,987 psi | 85% | 3373 fps | 99.8% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 37,188 psi | 53% | 2106 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 60,205 psi | 86% | 3281 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 59,915 psi | 86% | 3268 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 86% | 61,627 psi | 89% | 3304 fps | 99.9% |
| IMR 4350 | <<locked>> | 90% | 60,510 psi | 87% | 3317 fps | 99.8% |
| IMR 4451 Enduron | <<locked>> | 86% | 60,176 psi | 86% | 3304 fps | 99.9% |
| IMR 4831 | <<locked>> | 94% | 62,047 psi | 89% | 3343 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 94% | 59,640 psi | 86% | 3307 fps | 98.3% |
| IMR 7828 SSC | <<locked>> | 96% | 60,974 psi | 88% | 3442 fps | 99% |
| Lovex S062 | <<locked>> | 82% | 61,148 psi | 88% | 3268 fps | 100% |
| Lovex S065 | <<locked>> | 88% | 61,308 psi | 88% | 3304 fps | 100% |
| Lovex S070 | <<locked>> | 88% | 59,582 psi | 86% | 3301 fps | 99.9% |
| Lovex S071ᴾ | <<locked>> | 100% | 57,537 psi | 83% | 3264 fps | 100% |
| Norma 203B | <<locked>> | 82% | 62,236 psi | 89% | 3333 fps | 100% |
| Norma 204 | <<locked>> | 90% | 61,917 psi | 89% | 3379 fps | 99.5% |
| Norma 217ᴾ | <<locked>> | 100% | 40,799 psi | 59% | 3107 fps | 97.4% |
| Norma MRP | <<locked>> | 94% | 59,117 psi | 85% | 3425 fps | 99.9% |
| Norma URP | <<locked>> | 90% | 62,482 psi | 90% | 3376 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 61,221 psi | 88% | 3448 fps | 99.2% |
| Ramshot Hunter | <<locked>> | 90% | 61,366 psi | 88% | 3379 fps | 100% |
| Ramshot Magnum | <<locked>> | 96% | 58,523 psi | 84% | 3356 fps | 99.8% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 38,130 psi | 55% | 2156 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 82% | 59,930 psi | 86% | 3291 fps | 100% |
| ReloadSwiss RS 60 | <<locked>> | 84% | 62,120 psi | 89% | 3406 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 88% | 60,901 psi | 87% | 3366 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 90% | 62,990 psi | 90% | 3455 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 55,898 psi | 80% | 3435 fps | 100% |
| ReloadSwiss RS 80ᴾ | <<locked>> | 100% | 51,097 psi | 73% | 3307 fps | 96.5% |
| Rottweil R 903 | <<locked>> | 84% | 61,076 psi | 88% | 3291 fps | 100% |
| Rottweil R 904 | <<locked>> | 94% | 62,178 psi | 89% | 3356 fps | 98.9% |
| Rottweil R 905 | <<locked>> | 94% | 60,292 psi | 87% | 3373 fps | 99.5% |
| Rottweil R 907 | <<locked>> | 88% | 62,859 psi | 90% | 3340 fps | 99.9% |
| Shooters World Long Rifle | <<locked>> | 88% | 61,308 psi | 88% | 3304 fps | 100% |
| Shooters World Precision | <<locked>> | 82% | 61,148 psi | 88% | 3268 fps | 100% |
| Shooters World SW4350 | <<locked>> | 88% | 59,582 psi | 86% | 3301 fps | 99.9% |
| SNPE Vectan SP 11 | <<locked>> | 84% | 62,091 psi | 89% | 3346 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 84% | 59,944 psi | 86% | 3136 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 88% | 60,901 psi | 87% | 3251 fps | 99.9% |
| SNPE Vectan Tubal 8000 | <<locked>> | 94% | 59,814 psi | 86% | 3366 fps | 99.5% |
| Somchem S355 | <<locked>> | 84% | 60,176 psi | 86% | 3278 fps | 100% |
| Somchem S361 | <<locked>> | 92% | 60,597 psi | 87% | 3284 fps | 98.2% |
| Somchem S365 | <<locked>> | 90% | 59,379 psi | 85% | 3323 fps | 100% |
| Somchem S385 | <<locked>> | 94% | 61,192 psi | 88% | 3340 fps | 99.8% |
| Unknown powder | <<locked>> | 88% | 62,656 psi | 90% | 3379 fps | 100% |
| Vihtavuori N133 | <<locked>> | 82% | 61,989 psi | 89% | 3156 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 62,613 psi | 90% | 3228 fps | 100% |
| Vihtavuori N150 | <<locked>> | 90% | 62,004 psi | 89% | 3251 fps | 100% |
| Vihtavuori N160 | <<locked>> | 86% | 59,263 psi | 85% | 3284 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 62,178 psi | 89% | 3333 fps | 99.8% |
| Vihtavuori N540 | <<locked>> | 82% | 62,685 psi | 90% | 3261 fps | 100% |
| Vihtavuori N550 | <<locked>> | 86% | 59,959 psi | 86% | 3340 fps | 100% |
| Vihtavuori N555 | <<locked>> | 94% | 59,379 psi | 85% | 3346 fps | 100% |
| Vihtavuori N560 | <<locked>> | 96% | 59,321 psi | 85% | 3425 fps | 98.4% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 59,161 psi | 85% | 3392 fps | 98.6% |
| Vihtavuori N568ᴾ | <<locked>> | 100% | 51,880 psi | 75% | 3310 fps | 96% |
| Winchester 6.5 StaBALL | <<locked>> | 88% | 60,263 psi | 87% | 3255 fps | 100% |
| Winchester 760 | <<locked>> | 84% | 59,379 psi | 85% | 3353 fps | 99.9% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 62,627 psi | 90% | 3520 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 92% | 58,798 psi | 84% | 3297 fps | 99.3% |
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% | 52,692 psi | 76% | 3117 fps | 99% |
| Accurate 3100 | <<locked>> | 80% | 36,071 psi | 52% | 2844 fps | 96.9% |
| Accurate 4350 | <<locked>> | 80% | 47,239 psi | 68% | 3117 fps | 99.9% |
| Accurate MAGPRO | <<locked>> | 92% | 51,445 psi | 74% | 3264 fps | 95.5% |
| ADI APS 450 | <<locked>> | 80% | 58,958 psi | 85% | 2579 fps | 100% |
| ADI AR 2208 | <<locked>> | 80% | 54,056 psi | 78% | 3186 fps | 100% |
| ADI AR 2209 | <<locked>> | 82% | 41,524 psi | 60% | 3022 fps | 95.8% |
| ADI AR 2213 | <<locked>> | 88% | 45,455 psi | 65% | 3136 fps | 95.6% |
| ADI AR 2217 | <<locked>> | 96% | 43,888 psi | 63% | 3081 fps | 95.5% |
| ADI AR 2225 | <<locked>> | 92% | 35,143 psi | 50% | 2920 fps | 95.6% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 55,521 psi | 80% | 3215 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 59,016 psi | 85% | 3294 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 44,353 psi | 64% | 3114 fps | 99.9% |
| Alliant Reloder-17 | <<locked>> | 80% | 51,155 psi | 73% | 3241 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 80% | 39,102 psi | 56% | 2956 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 84% | 40,030 psi | 57% | 3018 fps | 95.6% |
| Alliant Reloder-23 | <<locked>> | 80% | 34,084 psi | 49% | 2867 fps | 99.3% |
| Alliant Reloder-25 | <<locked>> | 82% | 31,850 psi | 46% | 2822 fps | 96% |
| Alliant Reloder-26 | <<locked>> | 80% | 37,159 psi | 53% | 3012 fps | 98.7% |
| Baschieri & Pellagri 109 | <<locked>> | 96% | 57,014 psi | 82% | 3274 fps | 95.5% |
| Bofors RP15 | <<locked>> | 86% | 39,813 psi | 57% | 3012 fps | 95.3% |
| Bofors RP3 | <<locked>> | 80% | 57,130 psi | 82% | 3238 fps | 100% |
| Bofors RP30 | <<locked>> | 94% | 42,859 psi | 62% | 3110 fps | 95.8% |
| Bofors RP5 | <<locked>> | 84% | 40,030 psi | 57% | 3018 fps | 95.6% |
| Bofors RP7 | <<locked>> | 80% | 49,240 psi | 71% | 3107 fps | 98.6% |
| Hodgdon H1000 | <<locked>> | 94% | 42,308 psi | 61% | 3051 fps | 95.6% |
| Hodgdon H380 | <<locked>> | 80% | 56,840 psi | 82% | 3255 fps | 100% |
| Hodgdon H414 | <<locked>> | 80% | 52,156 psi | 75% | 3232 fps | 99.4% |
| Hodgdon H4350 | <<locked>> | 80% | 46,543 psi | 67% | 3087 fps | 97.5% |
| Hodgdon H4831 | <<locked>> | 92% | 48,240 psi | 69% | 3136 fps | 95.8% |
| Hodgdon H4831 SC | <<locked>> | 88% | 47,558 psi | 68% | 3120 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 42,221 psi | 61% | 2989 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 58,349 psi | 84% | 3291 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 88% | 37,420 psi | 54% | 3031 fps | 95.1% |
| Hodgdon Superformance | <<locked>> | 80% | 47,747 psi | 69% | 3176 fps | 98.7% |
| Hodgdon TrailBoss | <<locked>> | 80% | 28,007 psi | 40% | 1890 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 56,811 psi | 82% | 3228 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 53,185 psi | 76% | 3163 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,779 psi | 74% | 3136 fps | 99.3% |
| IMR 4350 | <<locked>> | 80% | 44,585 psi | 64% | 3025 fps | 97.7% |
| IMR 4451 Enduron | <<locked>> | 80% | 50,212 psi | 72% | 3130 fps | 99% |
| IMR 4831 | <<locked>> | 80% | 40,799 psi | 59% | 2969 fps | 99.3% |
| IMR 4955 Enduron | <<locked>> | 86% | 46,804 psi | 67% | 3071 fps | 95.6% |
| IMR 7828 SSC | 99.2 gr | 86% | 43,729 psi | 63% | 3110 fps | 95.2% |
| Lovex S062 | <<locked>> | 80% | 57,754 psi | 83% | 3219 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 48,486 psi | 70% | 3084 fps | 99.6% |
| Lovex S070 | <<locked>> | 80% | 46,804 psi | 67% | 3071 fps | 98.7% |
| Lovex S071 | <<locked>> | 80% | 31,430 psi | 45% | 2717 fps | 95.1% |
| Norma 203B | <<locked>> | 80% | 58,392 psi | 84% | 3278 fps | 100% |
| Norma 204 | <<locked>> | 80% | 44,585 psi | 64% | 3064 fps | 96.6% |
| Norma 217 | <<locked>> | 96% | 36,042 psi | 52% | 2979 fps | 95.5% |
| Norma MRP | 93.7 gr | 80% | 36,796 psi | 53% | 2969 fps | 96% |
| Norma URP | <<locked>> | 80% | 45,745 psi | 66% | 3094 fps | 99.8% |
| Ramshot Grand | <<locked>> | 84% | 42,772 psi | 61% | 3097 fps | 95.3% |
| Ramshot Hunter | <<locked>> | 80% | 44,498 psi | 64% | 3084 fps | 98.9% |
| Ramshot Magnum | <<locked>> | 84% | 37,782 psi | 54% | 2946 fps | 95.7% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 28,572 psi | 41% | 1936 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 56,144 psi | 81% | 3232 fps | 99.9% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 54,056 psi | 78% | 3291 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 46,760 psi | 67% | 3130 fps | 99.8% |
| ReloadSwiss RS 70 | <<locked>> | 80% | 44,701 psi | 64% | 3143 fps | 99.7% |
| ReloadSwiss RS 76 | <<locked>> | 86% | 34,635 psi | 50% | 2940 fps | 95.1% |
| ReloadSwiss RS 80 | <<locked>> | 98% | 47,485 psi | 68% | 3235 fps | 95.5% |
| Rottweil R 903 | <<locked>> | 80% | 53,896 psi | 77% | 3182 fps | 100% |
| Rottweil R 904 | <<locked>> | 82% | 42,917 psi | 62% | 2995 fps | 95% |
| Rottweil R 905 | <<locked>> | 80% | 38,537 psi | 55% | 2940 fps | 95.1% |
| Rottweil R 907 | <<locked>> | 80% | 49,240 psi | 71% | 3107 fps | 98.6% |
| Shooters World Long Rifle | <<locked>> | 80% | 48,486 psi | 70% | 3084 fps | 99.6% |
| Shooters World Precision | <<locked>> | 80% | 57,754 psi | 83% | 3219 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 46,804 psi | 67% | 3071 fps | 98.7% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 54,592 psi | 78% | 3235 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 53,171 psi | 76% | 3041 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 47,427 psi | 68% | 3022 fps | 98.7% |
| SNPE Vectan Tubal 8000 | <<locked>> | 82% | 40,712 psi | 58% | 2999 fps | 95.8% |
| Somchem S355 | <<locked>> | 80% | 53,490 psi | 77% | 3176 fps | 100% |
| Somchem S361 | <<locked>> | 84% | 46,847 psi | 67% | 3041 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 42,830 psi | 62% | 3051 fps | 100% |
| Somchem S385 | <<locked>> | 80% | 39,436 psi | 57% | 2930 fps | 96.3% |
| Unknown powder | <<locked>> | 80% | 48,689 psi | 70% | 3150 fps | 99.8% |
| Vihtavuori N133 | <<locked>> | 80% | 58,624 psi | 84% | 3114 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 58,987 psi | 85% | 3179 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 46,122 psi | 66% | 3005 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 49,023 psi | 70% | 3117 fps | 100% |
| Vihtavuori N165 | <<locked>> | 84% | 37,753 psi | 54% | 2877 fps | 95.4% |
| Vihtavuori N540 | <<locked>> | 80% | 58,958 psi | 85% | 3212 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 49,777 psi | 72% | 3169 fps | 100% |
| Vihtavuori N555 | <<locked>> | 80% | 38,247 psi | 55% | 2956 fps | 99.3% |
| Vihtavuori N560 | 100.9 gr | 88% | 45,600 psi | 66% | 3166 fps | 95.3% |
| Vihtavuori N565 | <<locked>> | 92% | 45,614 psi | 66% | 3140 fps | 95.7% |
| Vihtavuori N568 | <<locked>> | 98% | 48,573 psi | 70% | 3241 fps | 95.1% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 46,079 psi | 66% | 3035 fps | 100% |
| Winchester 760 | <<locked>> | 80% | 52,156 psi | 75% | 3232 fps | 99.4% |
| Winchester StaBALL HD | <<locked>> | 80% | 30,676 psi | 44% | 2887 fps | 99.5% |
| Winchester Supreme 780 | <<locked>> | 80% | 38,986 psi | 56% | 2913 fps | 95.1% |
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 98 powders for .338 Lapua Mag. Ackley Improved loaded with the .338 | 175gr | Barnes X S. Winchester StaBALL HD delivers the highest muzzle velocity at 3,520 fps; across all powders the maximum-charge window runs from 2,106 fps to 3,520 fps. ADI AR 2217 gives the best case fill at 100 %, and 98 of the 98 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (480 MPa), the top charges use 53–90 %, leaving at least 10 % headroom. The 175.0 gr projectile in 0.338" calls for a 1:16.0 twist; slower twists will usually not stabilise this weight. ADI AR 2217, ADI AR 2225, Alliant Reloder-25 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. IMR 7828 SSC, Vihtavuori N560, Norma MRP rank at the top here: for .338 Lapua Mag. Ackley Improved with the .338 | 175gr | Barnes X S they combine a high case fill with complete burn and sit in the upper velocity band. As outliers, Alliant Reloder-33, IMR 7977 Enduron, IMR 8133 Enduron 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.