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358 Norma Magnum Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 358 Norma Magnum 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.

358 Norma Magnum reference

Maximum average pressure (MAP)4,400 BAR
Nominal case capacity91.5 gr H₂O
Groove / bullet diameter0.358 in (9.10 mm)

Example simulation illustrative

Bullet
Hornady 0.358 250 gr InterLock RN
Powder
IMR 4350
Charge
64.3 gr
Barrel
25.5 in

Muzzle velocity

2,449 fps

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

32,904 – 41,892 – 52,235 psi

nominal is 66% of the 63,817 psi maximum average pressure

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.

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