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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 load. 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
69.1 gr
Barrel
25.5 in

Muzzle velocity

2,585 fps

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

38,257 – 47,307 – 57,354 psi

nominal is 74% MAP (63,817 psi)

The simulator isn't optimized for this cartridge yet: there isn't enough published pressure data to check it.

Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.

Popular 358 Norma Magnum powders

Powders and bullets handloaders commonly use for the 358 Norma Magnum, drawn from public discussion and listed most common first. They appear as the Popular group in the calculator's pickers. This is not a load recommendation — always check your load against a current published manual.

Popular 358 Norma Magnum bullets

Use MyLoads as a 358 Norma Magnum velocity and pressure calculator: it estimates muzzle velocity, muzzle energy and the full chamber-pressure curve for your own powder, charge and barrel length, compared against the reference facts above.

Open the 358 Norma Magnum in the MyLoads calculator →

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