How many powder charges should you use?
Use the charge count that belongs to the current firing solution for the measured target range. The official Steam description explicitly links driving the charges higher or lower with the ballistic calculator and gun elevation, so a charge count should not be chosen in isolation.
This guide does not publish a universal number because the correct value depends on the current target and verified game data.
Why the charge count changes elevation
Changing propellant changes the ballistic setup. Keep the calculator input, the charge count you intend to load, and the elevation you set on the gun aligned. After any charge-count change, run the calculation again rather than reusing the previous elevation.
If you are running low on powder
The developer FAQ describes the Requisition Console as a source of additional powder charges and other mission support. If supply is the limiting factor, check requisition options instead of forcing a different firing solution without recalculating it.
Seeing a not enough charges problem?
If the game reports that you do not have enough charges or your elevation setup no longer matches the available powder, use the dedicated troubleshooting page. It separates supply, loaded-gun, and recalculation checks from the general powder-charge mechanic.