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8x57 IRS Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 8x57 IRS with the free, in-browser MyLoads internal-ballistics simulator. The figures below are illustrative estimates from a physics model — not a recommended recipe. Always cross-check a current published loading manual.

8x57 IRS reference

Maximum average pressure (MAP)3,300 BAR
Nominal case capacity63.0 gr H₂O
Groove / bullet diameter0.323 in (8.20 mm)

Example simulation illustrative

Bullet
Sierra 8mm .323 Caliber (.323) 220 gr SBT GameKing
Powder
Lovex (Explosia) S062
Charge
44 gr
Barrel
23.5 in

Muzzle velocity

2,234 fps

Peak chamber pressure (interval, ±10% burn-rate)

37,211 – 46,628 – 57,427 psi

nominal is 97% of the 47,862 psi maximum average pressure

This sample load runs near the maximum average pressure for the 8x57 IRS (about 97% of MAP at the nominal estimate; the upper interval can exceed it). It is shown only to illustrate the simulator — reduce the charge and work up from your manual's start load.

Illustrative example — every figure here is an estimate and can be wrong. Always consult a current published loading manual, and never trust these numbers on their own.

Open the 8x57 IRS in the MyLoads calculator →

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