Load Specifications
Bullet:.338 | 220gr | Atomic 29 HP
Bullet Manufacturer:Atomic 29
Bullet Weight:220 gr
Bullet Diameter:0.338"
Bullet Length:<<locked>>
Caliber:8.5 mm Messner Mag. load data
Case Length (l3):2.508"
Cartridge Length (C.O.L.):<<locked>>
Case Capacity:106 Grains of Water
Primer Size:Large Rifle Magnum (LRM)
Barrel Length:25.6"
Max. allowed Pressure:63,817 psi
Recommended Twist Rate:1:14.0
Load data in caliber 8.5 mm Messner Mag. with .338 | 220gr | Atomic 29 HP bullet and 99 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are Alliant Reloder-26, ReloadSwiss RS 70 and Alliant Reloder-17.
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: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 82% | 55,085 psi | 86% | 2746 fps | 100% |
| Accurate 2700 | <<locked>> | 84% | 56,724 psi | 89% | 2828 fps | 99.4% |
| Accurate 3100ᴾ | <<locked>> | 100% | 54,404 psi | 85% | 2871 fps | 99.9% |
| Accurate 4064 | <<locked>> | 84% | 55,564 psi | 87% | 2802 fps | 100% |
| Accurate 4350 | <<locked>> | 92% | 56,739 psi | 89% | 2920 fps | 100% |
| Accurate MAGPROᴾ | <<locked>> | 100% | 57,145 psi | 90% | 3025 fps | 97.4% |
| ADI AR 2208 | <<locked>> | 86% | 55,985 psi | 88% | 2841 fps | 100% |
| ADI AR 2209 | <<locked>> | 96% | 54,288 psi | 85% | 2917 fps | 98.7% |
| ADI AR 2213ᴾ | <<locked>> | 100% | 55,550 psi | 87% | 2969 fps | 98% |
| Alliant Power Pro 2000-MR | <<locked>> | 82% | 55,477 psi | 87% | 2966 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 96% | 54,288 psi | 85% | 2913 fps | 98.7% |
| Alliant Reloder- TS 15.5 | <<locked>> | 86% | 56,768 psi | 89% | 2861 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 84% | 57,029 psi | 89% | 2887 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 94% | 57,711 psi | 90% | 2976 fps | 100% |
| Alliant Reloder-17 | <<locked>> | 88% | 55,361 psi | 87% | 2946 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 98% | 57,246 psi | 90% | 2959 fps | 99.1% |
| Alliant Reloder-22ᴾ | <<locked>> | 100% | 54,462 psi | 85% | 2966 fps | 98.9% |
| Alliant Reloder-23ᴾ | <<locked>> | 100% | 51,329 psi | 80% | 2887 fps | 100% |
| Alliant Reloder-25ᴾ | <<locked>> | 100% | 44,628 psi | 70% | 2825 fps | 99.7% |
| Alliant Reloder-26 | <<locked>> | 98% | 55,245 psi | 87% | 3031 fps | 100% |
| Bofors RP15ᴾ | <<locked>> | 100% | 49,850 psi | 78% | 2887 fps | 98.1% |
| Bofors RP3 | <<locked>> | 86% | 57,740 psi | 90% | 2881 fps | 100% |
| Bofors RP5ᴾ | <<locked>> | 100% | 54,462 psi | 85% | 2966 fps | 98.9% |
| Bofors RP7 | <<locked>> | 90% | 56,971 psi | 89% | 2874 fps | 99.5% |
| Hodgdon H1000ᴾ | <<locked>> | 100% | 44,309 psi | 69% | 2759 fps | 96.2% |
| Hodgdon H380 | <<locked>> | 84% | 54,404 psi | 85% | 2848 fps | 100% |
| Hodgdon H414 | <<locked>> | 90% | 55,347 psi | 87% | 2923 fps | 99.7% |
| Hodgdon H4350 | <<locked>> | 88% | 55,056 psi | 86% | 2881 fps | 99% |
| Hodgdon H4831 | <<locked>> | 98% | 55,767 psi | 87% | 2913 fps | 97.4% |
| Hodgdon H4831 SC | <<locked>> | 98% | 54,476 psi | 85% | 2894 fps | 97.1% |
| Hodgdon Hybrid 100V | <<locked>> | 94% | 54,360 psi | 85% | 2848 fps | 100% |
| Hodgdon LEVERevolution | <<locked>> | 82% | 55,724 psi | 87% | 2881 fps | 100% |
| Hodgdon Retumboᴾ | <<locked>> | 100% | 43,613 psi | 68% | 2858 fps | 97.6% |
| Hodgdon Superformance | <<locked>> | 90% | 55,811 psi | 87% | 2966 fps | 99.6% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 36,376 psi | 57% | 1768 fps | 100% |
| Hodgdon VARGET | <<locked>> | 82% | 56,449 psi | 88% | 2844 fps | 100% |
| IMR 4064 | <<locked>> | 84% | 55,390 psi | 87% | 2822 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 82% | 54,462 psi | 85% | 2808 fps | 99.5% |
| IMR 4350 | <<locked>> | 92% | 54,636 psi | 86% | 2854 fps | 99.3% |
| IMR 4451 Enduron | <<locked>> | 88% | 55,303 psi | 87% | 2848 fps | 99.6% |
| IMR 4831 | <<locked>> | 94% | 57,116 psi | 90% | 2910 fps | 100% |
| IMR 4895 | <<locked>> | 82% | 54,839 psi | 86% | 2861 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 98% | 57,188 psi | 90% | 2897 fps | 97.7% |
| IMR 7828 SSCᴾ | <<locked>> | 100% | 52,881 psi | 83% | 2943 fps | 97.6% |
| Lovex S060 | <<locked>> | 82% | 56,985 psi | 89% | 2808 fps | 100% |
| Lovex S062 | <<locked>> | 84% | 55,579 psi | 87% | 2815 fps | 100% |
| Lovex S065 | <<locked>> | 90% | 55,129 psi | 86% | 2841 fps | 100% |
| Lovex S070 | <<locked>> | 92% | 56,449 psi | 88% | 2884 fps | 99.8% |
| Lovex S071ᴾ | <<locked>> | 100% | 45,165 psi | 71% | 2726 fps | 99.1% |
| Norma 201 | <<locked>> | 82% | 56,826 psi | 89% | 2825 fps | 100% |
| Norma 202 | <<locked>> | 82% | 57,725 psi | 90% | 2818 fps | 100% |
| Norma 203B | <<locked>> | 84% | 56,318 psi | 88% | 2871 fps | 100% |
| Norma 204 | <<locked>> | 92% | 55,492 psi | 87% | 2910 fps | 98.7% |
| Norma MRP | <<locked>> | 98% | 54,041 psi | 85% | 2989 fps | 99.7% |
| Norma URP | <<locked>> | 92% | 55,434 psi | 87% | 2907 fps | 100% |
| Ramshot Big Game | <<locked>> | 84% | 57,319 psi | 90% | 2900 fps | 100% |
| Ramshot Grandᴾ | <<locked>> | 100% | 53,301 psi | 84% | 2956 fps | 98% |
| Ramshot Hunter | <<locked>> | 92% | 54,418 psi | 85% | 2913 fps | 99.9% |
| Ramshot Magnumᴾ | <<locked>> | 100% | 47,384 psi | 74% | 2828 fps | 98.4% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 37,072 psi | 58% | 1811 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 84% | 54,447 psi | 85% | 2835 fps | 99.8% |
| ReloadSwiss RS 60 | <<locked>> | 86% | 54,708 psi | 86% | 2936 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 92% | 56,797 psi | 89% | 2946 fps | 100% |
| ReloadSwiss RS 70 | <<locked>> | 92% | 55,361 psi | 87% | 2979 fps | 100% |
| ReloadSwiss RS 76ᴾ | <<locked>> | 100% | 43,482 psi | 68% | 2851 fps | 98.5% |
| Rottweil R 902 | <<locked>> | 84% | 57,348 psi | 90% | 2822 fps | 100% |
| Rottweil R 903 | <<locked>> | 86% | 54,012 psi | 85% | 2825 fps | 100% |
| Rottweil R 904 | <<locked>> | 96% | 55,840 psi | 88% | 2884 fps | 98% |
| Rottweil R 905 | <<locked>> | 98% | 56,362 psi | 88% | 2946 fps | 99.1% |
| Rottweil R 907 | <<locked>> | 90% | 56,971 psi | 89% | 2874 fps | 99.5% |
| Shooters World Long Rifle | <<locked>> | 90% | 55,129 psi | 86% | 2841 fps | 100% |
| Shooters World Precision | <<locked>> | 84% | 55,579 psi | 87% | 2815 fps | 100% |
| Shooters World SW4350 | <<locked>> | 92% | 56,449 psi | 88% | 2884 fps | 99.8% |
| SNPE Vectan SP 11 | <<locked>> | 86% | 55,854 psi | 88% | 2887 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 82% | 56,811 psi | 89% | 2858 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 82% | 57,580 psi | 90% | 2749 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 86% | 55,158 psi | 86% | 2710 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 90% | 54,824 psi | 86% | 2795 fps | 99.6% |
| SNPE Vectan Tubal 8000 | <<locked>> | 98% | 55,912 psi | 88% | 2940 fps | 99.1% |
| Somchem S335 | <<locked>> | 82% | 57,348 psi | 90% | 2746 fps | 100% |
| Somchem S355 | <<locked>> | 88% | 57,566 psi | 90% | 2871 fps | 100% |
| Somchem S361 | <<locked>> | 96% | 57,682 psi | 90% | 2877 fps | 97.6% |
| Somchem S365 | <<locked>> | 94% | 54,853 psi | 86% | 2904 fps | 100% |
| Somchem S385 | <<locked>> | 98% | 56,942 psi | 89% | 2920 fps | 99.6% |
| Vihtavuori N135 | <<locked>> | 82% | 54,418 psi | 85% | 2733 fps | 100% |
| Vihtavuori N140 | <<locked>> | 82% | 54,665 psi | 86% | 2749 fps | 100% |
| Vihtavuori N150 | <<locked>> | 88% | 55,550 psi | 87% | 2795 fps | 100% |
| Vihtavuori N160 | <<locked>> | 92% | 57,667 psi | 90% | 2900 fps | 100% |
| Vihtavuori N165ᴾ | <<locked>> | 100% | 52,605 psi | 82% | 2838 fps | 98.9% |
| Vihtavuori N540 | <<locked>> | 84% | 56,405 psi | 88% | 2799 fps | 100% |
| Vihtavuori N550 | <<locked>> | 92% | 56,753 psi | 89% | 2907 fps | 100% |
| Vihtavuori N555ᴾ | <<locked>> | 100% | 57,392 psi | 90% | 2966 fps | 100% |
| Vihtavuori N560 | <<locked>> | 98% | 54,331 psi | 85% | 2979 fps | 97.5% |
| Vihtavuori N565ᴾ | <<locked>> | 100% | 46,079 psi | 72% | 2822 fps | 95.9% |
| Winchester 6.5 StaBALL | <<locked>> | 92% | 57,595 psi | 90% | 2864 fps | 100% |
| Winchester 760 | <<locked>> | 90% | 55,550 psi | 87% | 2927 fps | 99.7% |
| Winchester StaBALL HDᴾ | <<locked>> | 100% | 46,543 psi | 73% | 2953 fps | 100% |
| Winchester StaBALL Match | <<locked>> | 82% | 56,913 psi | 89% | 2864 fps | 100% |
| Winchester Supreme 780ᴾ | <<locked>> | 100% | 57,319 psi | 90% | 2917 fps | 99% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 25.6"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2495 | <<locked>> | 80% | 51,387 psi | 81% | 2697 fps | 100% |
| Accurate 2700 | <<locked>> | 80% | 49,574 psi | 78% | 2717 fps | 98.5% |
| Accurate 3100 | <<locked>> | 84% | 31,227 psi | 49% | 2428 fps | 95.4% |
| Accurate 4064 | <<locked>> | 80% | 48,747 psi | 76% | 2707 fps | 100% |
| Accurate 4350 | <<locked>> | 80% | 37,333 psi | 59% | 2585 fps | 98.9% |
| Accurate MAGPRO | <<locked>> | 96% | 49,284 psi | 77% | 2897 fps | 95.7% |
| ADI AR 2208 | <<locked>> | 80% | 46,427 psi | 73% | 2690 fps | 100% |
| ADI AR 2209 | <<locked>> | 86% | 38,885 psi | 61% | 2625 fps | 95% |
| ADI AR 2213 | <<locked>> | 94% | 45,353 psi | 71% | 2789 fps | 95.6% |
| Alliant Power Pro 2000-MR | <<locked>> | 80% | 51,721 psi | 81% | 2910 fps | 100% |
| Alliant Power Pro Varmint | <<locked>> | 86% | 38,972 psi | 61% | 2625 fps | 95.2% |
| Alliant Reloder- TS 15.5 | <<locked>> | 80% | 46,876 psi | 73% | 2713 fps | 100% |
| Alliant Reloder-15 | <<locked>> | 80% | 50,183 psi | 79% | 2782 fps | 100% |
| Alliant Reloder-16 | <<locked>> | 80% | 36,463 psi | 57% | 2598 fps | 99% |
| Alliant Reloder-17 | 73.7 gr | 80% | 41,524 psi | 65% | 2723 fps | 100% |
| Alliant Reloder-19 | <<locked>> | 86% | 38,580 psi | 60% | 2618 fps | 95.1% |
| Alliant Reloder-22 | <<locked>> | 90% | 38,725 psi | 61% | 2667 fps | 95.3% |
| Alliant Reloder-23 | <<locked>> | 80% | 26,469 psi | 41% | 2349 fps | 96.9% |
| Alliant Reloder-25 | <<locked>> | 88% | 30,211 psi | 47% | 2474 fps | 95.3% |
| Alliant Reloder-26 | 75.5 gr | 80% | 28,210 psi | 44% | 2454 fps | 95.2% |
| Bofors RP15 | <<locked>> | 92% | 38,203 psi | 60% | 2654 fps | 95% |
| Bofors RP3 | <<locked>> | 80% | 47,065 psi | 74% | 2723 fps | 100% |
| Bofors RP5 | <<locked>> | 90% | 38,725 psi | 61% | 2667 fps | 95.3% |
| Bofors RP7 | <<locked>> | 80% | 41,495 psi | 65% | 2602 fps | 97.1% |
| Hodgdon H1000 | <<locked>> | 98% | 41,336 psi | 65% | 2694 fps | 95.1% |
| Hodgdon H380 | <<locked>> | 80% | 47,572 psi | 75% | 2736 fps | 99.8% |
| Hodgdon H414 | <<locked>> | 80% | 39,465 psi | 62% | 2635 fps | 97.2% |
| Hodgdon H4350 | <<locked>> | 80% | 42,395 psi | 66% | 2654 fps | 96.6% |
| Hodgdon H4831 | <<locked>> | 94% | 48,544 psi | 76% | 2795 fps | 95.8% |
| Hodgdon H4831 SC | <<locked>> | 94% | 47,630 psi | 75% | 2776 fps | 95.6% |
| Hodgdon Hybrid 100V | <<locked>> | 80% | 34,040 psi | 53% | 2490 fps | 99.4% |
| Hodgdon LEVERevolution | <<locked>> | 80% | 52,127 psi | 82% | 2828 fps | 100% |
| Hodgdon Retumbo | <<locked>> | 96% | 38,247 psi | 60% | 2730 fps | 95.6% |
| Hodgdon Superformance | <<locked>> | 80% | 38,377 psi | 60% | 2644 fps | 96.5% |
| Hodgdon TrailBoss | <<locked>> | 80% | 27,166 psi | 43% | 1578 fps | 100% |
| Hodgdon VARGET | <<locked>> | 80% | 52,852 psi | 83% | 2792 fps | 100% |
| IMR 4064 | <<locked>> | 80% | 48,834 psi | 77% | 2723 fps | 100% |
| IMR 4166 Enduron | <<locked>> | 80% | 51,198 psi | 80% | 2756 fps | 99.2% |
| IMR 4350 | <<locked>> | 80% | 37,188 psi | 58% | 2530 fps | 95.8% |
| IMR 4451 Enduron | <<locked>> | 80% | 42,946 psi | 67% | 2631 fps | 97.8% |
| IMR 4831 | <<locked>> | 80% | 35,897 psi | 56% | 2536 fps | 98.6% |
| IMR 4895 | <<locked>> | 80% | 51,488 psi | 81% | 2812 fps | 100% |
| IMR 4955 Enduron | <<locked>> | 92% | 47,384 psi | 74% | 2736 fps | 95.7% |
| IMR 7828 SSC | <<locked>> | 94% | 43,120 psi | 68% | 2756 fps | 95% |
| Lovex S060 | <<locked>> | 80% | 53,621 psi | 84% | 2759 fps | 100% |
| Lovex S062 | <<locked>> | 80% | 49,052 psi | 77% | 2717 fps | 100% |
| Lovex S065 | <<locked>> | 80% | 40,277 psi | 63% | 2579 fps | 98.4% |
| Lovex S070 | <<locked>> | 80% | 38,522 psi | 60% | 2562 fps | 97.1% |
| Lovex S071 | <<locked>> | 88% | 30,356 psi | 48% | 2405 fps | 95% |
| Norma 201 | <<locked>> | 80% | 53,200 psi | 83% | 2772 fps | 100% |
| Norma 202 | <<locked>> | 80% | 54,041 psi | 85% | 2769 fps | 100% |
| Norma 203B | <<locked>> | 80% | 49,545 psi | 78% | 2769 fps | 100% |
| Norma 204 | <<locked>> | 82% | 39,276 psi | 62% | 2615 fps | 95.1% |
| Norma MRP | <<locked>> | 86% | 35,288 psi | 55% | 2618 fps | 95.6% |
| Norma URP | <<locked>> | 80% | 37,246 psi | 58% | 2582 fps | 98.7% |
| Ramshot Big Game | <<locked>> | 80% | 50,038 psi | 78% | 2795 fps | 100% |
| Ramshot Grand | <<locked>> | 94% | 42,786 psi | 67% | 2762 fps | 95.3% |
| Ramshot Hunter | <<locked>> | 80% | 36,158 psi | 57% | 2569 fps | 97% |
| Ramshot Magnum | <<locked>> | 94% | 38,029 psi | 60% | 2641 fps | 95.8% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 27,543 psi | 43% | 1614 fps | 100% |
| ReloadSwiss RS 50 | <<locked>> | 80% | 47,630 psi | 75% | 2723 fps | 99.2% |
| ReloadSwiss RS 60 | <<locked>> | 80% | 44,179 psi | 69% | 2772 fps | 100% |
| ReloadSwiss RS 62 | <<locked>> | 80% | 37,115 psi | 58% | 2602 fps | 98.6% |
| ReloadSwiss RS 70 | 74.9 gr | 80% | 36,187 psi | 57% | 2615 fps | 98.1% |
| ReloadSwiss RS 76 | <<locked>> | 94% | 35,157 psi | 55% | 2644 fps | 95.4% |
| Rottweil R 902 | <<locked>> | 80% | 50,821 psi | 80% | 2730 fps | 100% |
| Rottweil R 903 | <<locked>> | 80% | 44,324 psi | 69% | 2671 fps | 100% |
| Rottweil R 904 | <<locked>> | 88% | 43,149 psi | 68% | 2664 fps | 95.2% |
| Rottweil R 905 | <<locked>> | 86% | 37,666 psi | 59% | 2602 fps | 95% |
| Rottweil R 907 | <<locked>> | 80% | 41,495 psi | 65% | 2602 fps | 97.1% |
| Shooters World Long Rifle | <<locked>> | 80% | 40,277 psi | 63% | 2579 fps | 98.4% |
| Shooters World Precision | <<locked>> | 80% | 49,052 psi | 77% | 2717 fps | 100% |
| Shooters World SW4350 | <<locked>> | 80% | 38,522 psi | 60% | 2562 fps | 97.1% |
| SNPE Vectan SP 11 | <<locked>> | 80% | 45,745 psi | 72% | 2730 fps | 100% |
| SNPE Vectan SP 9 | <<locked>> | 80% | 53,272 psi | 83% | 2808 fps | 100% |
| SNPE Vectan Tubal 3000 | <<locked>> | 80% | 54,259 psi | 85% | 2707 fps | 100% |
| SNPE Vectan Tubal 5000 | <<locked>> | 80% | 45,861 psi | 72% | 2575 fps | 100% |
| SNPE Vectan Tubal 7000 | <<locked>> | 80% | 39,407 psi | 62% | 2526 fps | 97.1% |
| SNPE Vectan Tubal 8000 | <<locked>> | 88% | 39,842 psi | 62% | 2654 fps | 95.7% |
| Somchem S335 | <<locked>> | 80% | 53,751 psi | 84% | 2700 fps | 100% |
| Somchem S355 | <<locked>> | 80% | 44,628 psi | 70% | 2667 fps | 100% |
| Somchem S361 | <<locked>> | 90% | 47,166 psi | 74% | 2710 fps | 95.4% |
| Somchem S365 | <<locked>> | 80% | 33,678 psi | 53% | 2536 fps | 99.9% |
| Somchem S385 | <<locked>> | 84% | 35,708 psi | 56% | 2530 fps | 95.3% |
| Vihtavuori N135 | <<locked>> | 80% | 51,227 psi | 80% | 2690 fps | 100% |
| Vihtavuori N140 | <<locked>> | 80% | 51,343 psi | 80% | 2703 fps | 100% |
| Vihtavuori N150 | <<locked>> | 80% | 42,685 psi | 67% | 2598 fps | 100% |
| Vihtavuori N160 | <<locked>> | 80% | 38,711 psi | 61% | 2582 fps | 99% |
| Vihtavuori N165 | <<locked>> | 90% | 37,681 psi | 59% | 2566 fps | 95.5% |
| Vihtavuori N540 | <<locked>> | 80% | 49,574 psi | 78% | 2700 fps | 100% |
| Vihtavuori N550 | <<locked>> | 80% | 38,087 psi | 60% | 2582 fps | 98.7% |
| Vihtavuori N555 | <<locked>> | 80% | 29,240 psi | 46% | 2425 fps | 97% |
| Vihtavuori N560 | <<locked>> | 94% | 47,398 psi | 74% | 2858 fps | 95.9% |
| Vihtavuori N565 | <<locked>> | 98% | 42,946 psi | 67% | 2762 fps | 95% |
| Winchester 6.5 StaBALL | <<locked>> | 80% | 37,782 psi | 59% | 2549 fps | 99.9% |
| Winchester 760 | <<locked>> | 80% | 39,595 psi | 62% | 2638 fps | 97.2% |
| Winchester StaBALL HD | <<locked>> | 80% | 23,322 psi | 37% | 2316 fps | 95.6% |
| Winchester StaBALL Match | <<locked>> | 80% | 53,287 psi | 84% | 2812 fps | 100% |
| Winchester Supreme 780 | <<locked>> | 90% | 40,321 psi | 63% | 2628 fps | 95.7% |
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 99 powders for 8.5 mm Messner Mag. loaded with the .338 | 220gr | Atomic 29 HP. Alliant Reloder-26 delivers the highest muzzle velocity at 3,031 fps; across all powders the maximum-charge window runs from 1,768 fps to 3,031 fps. Accurate 3100 gives the best case fill at 100 %, and 99 of the 99 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (440 MPa), the top charges use 57–90 %, leaving at least 10 % headroom. The 220.0 gr projectile in 0.338" calls for a 1:14.0 twist; slower twists will usually not stabilise this weight. Accurate 3100, Accurate MAGPRO, ADI AR 2213 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. Alliant Reloder-26, ReloadSwiss RS 70, Alliant Reloder-17 rank at the top here: for 8.5 mm Messner Mag. with the .338 | 220gr | Atomic 29 HP they combine a high case fill with complete burn and sit in the upper velocity band. Always begin at the start load and work up in small increments while checking case and primer for pressure signs.