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30-40 Krag Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 30-40 Krag 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.

30-40 Krag reference

Maximum average pressure (MAP)40,000 CUP
Nominal case capacity58.0 gr H₂O
Groove / bullet diameter0.308 in (7.82 mm)

Example simulation illustrative

Bullet
Hornady 0.308 165 gr GMX
Powder
Vihtavuori N-160
Charge
41.1 gr
Barrel
30 in

Muzzle velocity

2,149 fps

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

19,345 – 24,635 – 30,551 psi

maximum average pressure for this cartridge is specified as 40,000 CUP (CUP is not directly comparable to this psi estimate)

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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