Estimate chamber pressure and muzzle velocity for the 9x21 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.
| Maximum average pressure (MAP) | 2,350 BAR |
|---|---|
| Nominal case capacity | 15.5 gr H₂O |
| Groove / bullet diameter | 0.356 in (9.03 mm) |
Muzzle velocity
Peak chamber pressure (interval, ±10% burn rate)
nominal is 65% MAP (34,084 psi)
Pressure for this powder is extrapolated from a velocity-only fit — the pressure figures carry extra uncertainty in both directions.
The simulator isn't optimized for this cartridge yet: there isn't enough published pressure data to check it.
Illustrative example — every figure is an estimate; always confirm your load against a current published manual before loading.
Powders handloaders commonly use for the 9x21, drawn from public discussion and listed most common first. They appear as the Popular group in the calculator's powder picker. This is not a load recommendation — always check your load against a current published manual.
Use MyLoads as a 9x21 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 9x21 in the MyLoads calculator →