Load Specifications
Load data in caliber 8 x 57 IRS with .323 | 127.7gr | Sax MJG-HSX bullet and 33 powders. The key underlying parameters are shown in the table above. The recommended powders for this cartridge and bullet combination are IMR 3031, Alliant AR-Comp and Vihtavuori N135.
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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Max Load - Barrel Length: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 92% | 41,626 psi | 87% | 2884 fps | 98.8% |
| Accurate 2460 | <<locked>> | 90% | 42,699 psi | 89% | 2920 fps | 96.4% |
| Accurate 2495ᴾ | <<locked>> | 100% | 41,568 psi | 87% | 2953 fps | 99.1% |
| Accurate 2520 | <<locked>> | 94% | 42,902 psi | 90% | 2963 fps | 96% |
| Accurate 4064ᴾ | <<locked>> | 100% | 38,624 psi | 81% | 2907 fps | 96.2% |
| Accurate LT-30 | <<locked>> | 84% | 42,032 psi | 88% | 2802 fps | 97.7% |
| Accurate LT-32 | <<locked>> | 84% | 42,409 psi | 89% | 2808 fps | 95.7% |
| ADI AR 2207 | <<locked>> | 82% | 41,727 psi | 87% | 2871 fps | 100% |
| ADI AR 2219 | <<locked>> | 86% | 42,322 psi | 88% | 2940 fps | 97.6% |
| Alliant AR-Comp | <<locked>> | 94% | 41,002 psi | 86% | 2966 fps | 100% |
| Alliant Reloder-10x | <<locked>> | 88% | 42,337 psi | 88% | 2920 fps | 99.6% |
| Alliant Reloder-7 | <<locked>> | 82% | 43,149 psi | 90% | 2871 fps | 99.8% |
| Baschieri & Pellagri 106 | <<locked>> | 86% | 43,134 psi | 90% | 2841 fps | 98.2% |
| Hodgdon H322 | <<locked>> | 88% | 41,249 psi | 86% | 2920 fps | 97.3% |
| Hodgdon H335 | <<locked>> | 88% | 41,887 psi | 88% | 2930 fps | 96.4% |
| Hodgdon TrailBossᴾ | <<locked>> | 100% | 32,256 psi | 67% | 1883 fps | 100% |
| IMR 3031 | <<locked>> | 96% | 41,394 psi | 86% | 2986 fps | 98.2% |
| IMR 4198 | <<locked>> | 86% | 41,510 psi | 87% | 2858 fps | 99.8% |
| Norma 200 | <<locked>> | 84% | 42,264 psi | 88% | 2897 fps | 99.8% |
| Norma 202 | <<locked>> | 96% | 42,293 psi | 88% | 2940 fps | 96.6% |
| ReloadSwiss RS 14ᴾ | <<locked>> | 100% | 32,300 psi | 67% | 1929 fps | 100% |
| Rottweil R 901 | <<locked>> | 92% | 41,292 psi | 86% | 2881 fps | 96% |
| SNPE Vectan SP 10 | <<locked>> | 86% | 43,062 psi | 90% | 2946 fps | 96.6% |
| SNPE Vectan SP 3 | <<locked>> | 88% | 43,076 psi | 90% | 2923 fps | 98.5% |
| SNPE Vectan Tubal 3000 | <<locked>> | 94% | 43,018 psi | 90% | 2854 fps | 96.6% |
| SNPE Vectan Tubal 5000ᴾ | <<locked>> | 100% | 41,524 psi | 87% | 2841 fps | 97.4% |
| Somchem S335 | <<locked>> | 94% | 41,626 psi | 87% | 2851 fps | 97.3% |
| Vihtavuori N120 | <<locked>> | 82% | 41,843 psi | 87% | 2828 fps | 100% |
| Vihtavuori N130 | <<locked>> | 90% | 43,062 psi | 90% | 2871 fps | 99.5% |
| Vihtavuori N133 | <<locked>> | 94% | 42,351 psi | 88% | 2864 fps | 98.8% |
| Vihtavuori N135ᴾ | <<locked>> | 100% | 42,772 psi | 89% | 2966 fps | 99.2% |
| Vihtavuori N140 | <<locked>> | 98% | 42,569 psi | 89% | 2917 fps | 97% |
| Vihtavuori N540 | <<locked>> | 98% | 41,176 psi | 86% | 2900 fps | 96.1% |
Recommended = one of the top powders for this cartridge and bullet combination.
Start Load - Barrel Length: 23.62"
| Powder | Charge | FR | MaxP | % | V(0) | z |
|---|---|---|---|---|---|---|
| Accurate 2015 | <<locked>> | 82% | 30,226 psi | 63% | 2612 fps | 95.6% |
| Accurate 2460 | <<locked>> | 88% | 39,856 psi | 83% | 2861 fps | 95.6% |
| Accurate 2495 | <<locked>> | 88% | 27,659 psi | 58% | 2615 fps | 95% |
| Accurate 2520 | <<locked>> | 92% | 39,987 psi | 84% | 2904 fps | 95.1% |
| Accurate 4064 | <<locked>> | 98% | 36,274 psi | 76% | 2851 fps | 95.4% |
| Accurate LT-30 | <<locked>> | 80% | 37,246 psi | 78% | 2697 fps | 96.4% |
| Accurate LT-32 | <<locked>> | 82% | 39,943 psi | 83% | 2756 fps | 95% |
| ADI AR 2207 | <<locked>> | 80% | 39,189 psi | 82% | 2818 fps | 100% |
| ADI AR 2219 | <<locked>> | 80% | 34,708 psi | 73% | 2762 fps | 95.2% |
| Alliant AR-Comp | 40.9 gr | 80% | 26,150 psi | 55% | 2566 fps | 96.4% |
| Alliant Reloder-10x | <<locked>> | 80% | 32,938 psi | 69% | 2703 fps | 97.8% |
| Alliant Reloder-7 | <<locked>> | 80% | 40,625 psi | 85% | 2822 fps | 99.6% |
| Baschieri & Pellagri 106 | <<locked>> | 80% | 35,549 psi | 74% | 2677 fps | 96.3% |
| Hodgdon H322 | <<locked>> | 84% | 36,027 psi | 75% | 2795 fps | 95.7% |
| Hodgdon H335 | <<locked>> | 86% | 39,233 psi | 82% | 2871 fps | 95.6% |
| Hodgdon TrailBoss | <<locked>> | 80% | 23,641 psi | 49% | 1680 fps | 100% |
| IMR 3031 | 44.9 gr | 88% | 32,082 psi | 67% | 2753 fps | 95.1% |
| IMR 4198 | <<locked>> | 80% | 34,664 psi | 72% | 2703 fps | 98.9% |
| Norma 200 | <<locked>> | 80% | 37,347 psi | 78% | 2792 fps | 99.3% |
| Norma 202 | <<locked>> | 92% | 37,144 psi | 78% | 2825 fps | 95% |
| ReloadSwiss RS 14 | <<locked>> | 80% | 23,598 psi | 49% | 1722 fps | 100% |
| Rottweil R 901 | <<locked>> | 90% | 38,870 psi | 81% | 2828 fps | 95.3% |
| SNPE Vectan SP 10 | <<locked>> | 84% | 40,074 psi | 84% | 2884 fps | 95.8% |
| SNPE Vectan SP 3 | <<locked>> | 80% | 33,431 psi | 70% | 2703 fps | 95.9% |
| SNPE Vectan Tubal 3000 | <<locked>> | 90% | 37,985 psi | 79% | 2749 fps | 95.1% |
| SNPE Vectan Tubal 5000 | <<locked>> | 94% | 34,519 psi | 72% | 2684 fps | 95.2% |
| Somchem S335 | <<locked>> | 88% | 34,650 psi | 72% | 2694 fps | 95.1% |
| Vihtavuori N120 | <<locked>> | 80% | 39,276 psi | 82% | 2779 fps | 100% |
| Vihtavuori N130 | <<locked>> | 80% | 31,705 psi | 66% | 2612 fps | 97.1% |
| Vihtavuori N133 | <<locked>> | 82% | 29,312 psi | 61% | 2556 fps | 95% |
| Vihtavuori N135 | 44 gr | 88% | 29,254 psi | 61% | 2641 fps | 95.4% |
| Vihtavuori N140 | <<locked>> | 94% | 37,507 psi | 78% | 2805 fps | 95.5% |
| Vihtavuori N540 | <<locked>> | 96% | 38,551 psi | 81% | 2841 fps | 95.2% |
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 33 powders for 8 x 57 IRS loaded with the .323 | 127.7gr | Sax MJG-HSX. IMR 3031 delivers the highest muzzle velocity at 2,986 fps; across all powders the maximum-charge window runs from 1,883 fps to 2,986 fps. Accurate 2495 gives the best case fill at 100 %, and 33 of the 33 powders fall inside the usable 80–100 % fill window.
Relative to the caliber's maximum pressure (330 MPa), the top charges use 67–90 %, leaving at least 10 % headroom. Accurate 2495, Accurate 4064, Hodgdon TrailBoss 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 3031, Alliant AR-Comp, Vihtavuori N135 rank at the top here: for 8 x 57 IRS with the .323 | 127.7gr | Sax MJG-HSX 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.