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400 Legend Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 400 Legend 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.

400 Legend reference

Maximum average pressure (MAP)45,000 psi
Nominal case capacity49.0 gr H₂O
Groove / bullet diameter0.400 in (10.16 mm)

Example simulation illustrative

Bullet
Hornady 0.400 200 gr XTP
Powder
IMR 4227
Charge
30.2 gr
Barrel
20 in

Muzzle velocity

2,048 fps

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

29,897 – 35,672 – 41,397 psi

nominal is 79% MAP (45,000 psi)

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

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

Popular 400 Legend powders

Powders and bullets handloaders commonly use for the 400 Legend, 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 400 Legend bullets

Use MyLoads as a 400 Legend 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 400 Legend in the MyLoads calculator →

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