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45 Colt Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 45 Colt 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.

45 Colt reference

Maximum average pressure (MAP)14,000 psi
Nominal case capacity41.8 gr H₂O
Groove / bullet diameter0.452 in (11.48 mm)

Example simulation illustrative

Bullet
Hornady 0.454 255 gr FP COWBOY
Powder
Winchester W231
Charge
5.6 gr
Barrel
4 in

Muzzle velocity

636 fps

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

11,703 – 12,266 – 12,778 psi

nominal is 88% MAP (14,000 psi)

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

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

Popular 45 Colt powders

Powders and bullets handloaders commonly use for the 45 Colt, 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 45 Colt bullets

Use MyLoads as a 45 Colt 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 45 Colt in the MyLoads calculator →

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