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327 Federal Magnum Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 327 Federal 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.

327 Federal Magnum reference

Maximum average pressure (MAP)45,000 psi
Nominal case capacity20.5 gr H₂O
Groove / bullet diameter0.312 in (7.92 mm)

Example simulation illustrative

Bullet
Hornady 0.312 100 gr XTP
Powder
Winchester W296
Charge
12.2 gr
Barrel
4 in

Muzzle velocity

1,242 fps

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

19,062 – 25,042 – 31,750 psi

nominal is 56% MAP (45,000 psi)

The simulator isn't optimized for this cartridge yet and may read pressure low and velocity low.

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

Popular 327 Federal Magnum powders

Powders and bullets handloaders commonly use for the 327 Federal 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 327 Federal Magnum bullets

Use MyLoads as a 327 Federal 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 327 Federal Magnum in the MyLoads calculator →

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