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7mm STW Load Data & Ballistics Calculator

Estimate chamber pressure and muzzle velocity for the 7mm STW 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.

7mm STW reference

Maximum average pressure (MAP)4,400 BAR
Nominal case capacity99.6 gr H₂O
Groove / bullet diameter0.284 in (7.21 mm)

Example simulation illustrative

Bullet
Hornady 0.284 162 gr SST
Powder
Alliant RL-19
Charge
65.4 gr
Barrel
26 in

Muzzle velocity

2,954 fps

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

46,733 – 59,321 – 72,449 psi

nominal is 93% of the 63,817 psi maximum average pressure

This sample load runs near the maximum average pressure for the 7mm STW (about 93% of MAP at the nominal estimate; the upper interval can exceed it). It is shown only to illustrate the simulator — reduce the charge and work up from your manual's start load.

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.

Open the 7mm STW in the MyLoads calculator →

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